Eco-friendly paver blocks with geotextiles for pedestrian footpaths and smart materials for bus station infrastructure

Abstract

The study examined bus stations in India to identify the potential causes of pedestrian footpath failures and defects in station building components. The factors such as increased pedestrian load, block settlement and environmental degradation significantly impact the long-term durability and performance of paver blocks. This research explores the use of geotextiles to enhance paver block strength and durability, allowing them to withstand heavy traffic while promoting environmental sustainability. Geotextiles, made of high-strength synthetic polymers, offer a sustainable alternative to cement, providing improved durability and eco-friendly benefits. A total of twelve samples with geo-textile ratios ranging from 20% to 60% were tested, yielding impressive mechanical properties including a compressive strength of 36 N/mm² and a flexural strength of 7.1 N/mm². The water absorption and fire resistance capacities exceeded those of conventional paver blocks. The integration of geotextiles also reduces manufacturing costs, construction expenses, environmental impact and resource consumption, offering a sustainable solution for footpath design. Additionally, the study recommends smart materials with applications for station components to enhance the sustainability of station infrastructure. These recommendations address the key issues in bus stations, improving the overall appearance, functionality and service efficiency of the infrastructure, tailored to the Indian context.

Keywords:
Bus station; Pedestrian footpath; Paver block; Geo-textiles; Smart materials

1. INTRODUCTION

Public transit facilities are the most cost-effective short-term solution for urban mobility. Bus transportation covers 90% of the public transportation in Indian cities. Bus stations are extensive infrastructure facilities specifically designed to handle passenger and vehicle flows, unlike bus stops which offer minimal space and functionality [¹, ²]. With the increasing demand for public transportation in recent years due to strategies such as optimizing bus routes, reduced fare collection methods and enhanced service quality, passenger traffic at transit stations has risen significantly [³]. As a result, there is a growing need to provide proper infrastructure that ensures safe and efficient pedestrian movement [⁴, ⁵].

Pedestrian footpath play a vital role in the bus station for providing safe, convenient and efficient walking surfaces for commuters [⁶, ⁷]. These pathways not only ensure pedestrian safety but also contribute to the aesthetic and functional value of the station infrastructure [⁸, ⁹]. However, footpaths are subjected to various challenges such as weathering, heavy pedestrian loads and environmental degradation, which can lead to structural damage, reduced durability and increased maintenance costs [¹⁰, ¹¹]. To address these issues, the construction industry has increasingly turned to innovative materials and techniques that enhance the durability, performance and sustainability of footpath infrastructure [¹², ¹³]. Nowadays, the use of industrial waste products has gained attention for the development of eco-friendly construction materials, such as concrete and paver blocks [¹⁴, ¹⁵]. Among these advancements, incorporating geo-textile fibres into paver blocks has emerged as a promising solution [¹⁶, ¹⁷]. The present study focuses on developing sustainable pedestrian paver blocks by utilizing geo-textile as a replacement material.

Paver blocks are modular, durable and interlocking units made from materials like concrete, clay or stone, used for surface paving in various applications such as roads, walkways, driveways and outdoor areas. They are designed for easy installation and maintenance, offering versatility in design and patterns [¹⁸]. They are highly durable, weather-resistant and can withstand heavy loads, making them ideal for pedestrian and vehicular traffic [¹⁹]. Additionally, their permeability helps to manage storm-water runoff [²⁰]. With eco-friendly options emerging, such as using recycled materials or geo-textiles, paver blocks are increasingly recognized for their sustainability and aesthetic value in transit station planning and construction.

Geo-textiles are synthetic fabrics, typically made from polymers such as polypropylene, polyester or polyethylene, that are widely used in construction. These materials are produced in various forms, including woven, knitted and non-woven fabrics and serve several critical functions, such as filtration, separation, reinforcement, drainage and stabilization [²¹, ²²]. They are particularly useful in enhancing the performance and longevity of construction materials, including paver blocks. Integrating geo-textile materials into paver blocks improves their mechanical properties, such as strength, durability and load distribution. The inclusion of geo-textiles reinforces the blocks, making them more resistant to cracking and shifting over time [²³]. This added strength helps ensure that the paver blocks can withstand high levels of pedestrian and vehicular traffic, as well as the stresses caused by environmental factors like temperature fluctuations and moisture changes [²⁴]. Furthermore, geo-textiles improve the flexibility and stability of the paver blocks, making them ideal for use in areas where ground movement or shifting could otherwise pose challenges. Another significant advantage is that geo-textiles contribute to the environmental sustainability of paver blocks. They can be made from recycled or waste materials, helping reduce the carbon footprint of construction projects and promoting eco-friendly practices in urban development [²⁵]. The use of geo-textile materials in paver block manufacturing offers significant economic and environmental benefits. From an economic standpoint, geo-textiles can be made from recycled materials, reducing the cost of production by lowering reliance on virgin raw materials, making it a more affordable alternative for large-scale construction projects. Additionally, by enhancing the strength, durability and load-bearing capacity of paver blocks, geo-textiles increase their lifespan, leading to lower maintenance and replacement costs over time. This contributes to long-term savings for construction companies and municipalities. The improved interlocking properties of geo-textile-reinforced paver blocks also facilitate faster and more efficient installation, reducing labor costs [²⁶].

Environmentally, geo-textiles play a crucial role in waste management by utilizing industrial waste or recycled materials, which helps divert waste from landfills and minimizes the need for new raw materials, thus promoting a circular economy. Moreover, incorporating geo-textiles into paver blocks supports sustainability in construction by improving surface permeability, aiding in better water management and reducing the risk of flooding. The use of recycled materials and reduced demand for new resources also leads to a decrease in carbon emissions associated with raw material extraction, transportation and manufacturing processes [²⁷]. Overall, the integration of geo-textiles in paver block production provides a balance between cost efficiency and environmental responsibility, aligning economic growth with sustainable practices.

The entire research is structured into two major phases. The first phase focuses on the manufacturing and testing of paver blocks designed to withstand pedestrian traffic while ensuring long-term durability. The second phase involves developing design recommendations for bus station infrastructure incorporating smart materials. This includes a comprehensive analysis of the properties and applications of these materials, which are categorized into energy harvesting materials, phase-changing materials, energy-efficient materials and other innovative types. Figure 1 illustrates the methodology employed in the research.

Figure 1
Research methodology.

2. MATERIALS USED

The sustainable manufacturing of paver blocks primarily utilizes geo-textiles, often blended with varying proportions of complementary materials. To fully harness the potential of geo-textile fibres in this application, a comprehensive understanding of their technical properties and specifications is essential, as these attributes play a critical role in determining the overall performance and durability of the paver blocks [²⁸].

Geo-textile fibres are known for their durability, tensile strength and resistance to environmental factors, all of which can enhance the structural integrity and lifespan of paver blocks. Analyzing properties such as fibre composition, melting point, elasticity and water absorption capacity is essential to understand their role in improving load-bearing capacity, resistance to wear and performance under varying environmental conditions. A thorough evaluation of these properties not only provides insights into their suitability for use in paver blocks, but also guides the development of optimized material combinations for enhanced functionality.

2.1. Fibres

High-performance geo-textile fibres are commonly produced from synthetic polymers such as Polypropylene, Polyester and Polyethylene, owing to their inherent strength characteristics [²⁹].

2.1.1. Polypropylene (PP)

Polypropylene having excellent chemical resistance, lightweight nature and durability. It is widely recognized for its outstanding chemical resistance, making it highly durable and resistant to corrosive substances. Its lightweight nature further enhances its usability in construction materials, as it contributes to reduced overall weight without compromising strength. Additionally, PP is known for its durability and ability to withstand prolonged exposure to environmental factors, such as moisture and temperature variations, without significant degradation. These properties make it an ideal choice for applications like paver blocks, where long-term performance, resistance to wear and structural integrity are critical. The incorporation of polypropylene in such materials can improve their load-bearing capacity, durability and overall lifespan, making it a valuable component in modern construction and material innovation.

2.1.2. Polyester (PET)

Polyester is highly regarded for its exceptional tensile strength and resistance to UV degradation, making it an ideal material for applications requiring enhanced structural integrity and load-bearing capacity. The high tensile strength of PET contributes to the overall durability and robustness of materials, particularly in environments subjected to significant mechanical stress. Furthermore, PET’s strong resistance to UV degradation ensures that it retains its physical and mechanical properties even when exposed to prolonged sunlight and harsh environmental conditions. These attributes make polyester a valuable component in paver blocks, where long-term durability, environmental resistance, and the ability to endure high stress are critical. The incorporation of PET fibres into paver blocks can significantly enhance their performance and lifespan in a wide range of construction applications.

2.1.3. Polyethylene (PE)

Polyethylene is a highly versatile polymer known for its exceptional flexibility, abrasion resistance and durability under harsh environmental conditions. It’s inherent resistance to wear and mechanical stress makes it suitable for use in demanding applications. Additionally, PE exhibits strong chemical resistance and maintains structural integrity across a wide range of temperatures, contributing to its reliable performance in adverse conditions. These properties have led to its widespread adoption in various sectors, including construction, packaging, automotive and industrial applications, where long-term resilience and performance are essential.

2.2. Grades of paving

The grading of paving blocks required for various traffic conditions, as outlined in IS 15658: 2006 – Specifications for Concrete Paving Blocks, is presented in Table 1.

Table 1
Recommended grades of paver block for different traffic conditions.

S.NO	COMPRESSIVE STRENGTH AT 28 DAYS, fck MPa	TRAFFIC CATEGORY	THICKNESS MIN (mm)	APPLICATIONS
1	M 30	Non-Traffic	50	Building premises, Monument premises, landscapes, public gardens/parks, domestic drives, paths and patios, embankment slopes and sand stabilization area
2	M 35	Light Traffic	60	Pedestrian plaza, shopping complex
3	M 40	Medium Traffic	80	Low volume traffic areas
4	M 50	Heavy Traffic	100	Bus terminal pavement / circulation area
5	M 55	Very Heavy Traffic	100	Bulk cargo handling areas

2.3. Physical requirements

Geo-textiles possess a range of key technical properties that influence their performance in various applications. Their tensile strength varies from 10 kN/m to over 200 kN/m, depending on the specific material and application requirements [³⁰, ³¹]. The thickness of geo-textile fibres typically falls between 50 mm and 100 mm, ensuring compatibility with the dimensions of paver blocks.

Additionally, geo-textiles are lightweight, with a mass per unit area ranging from 100 g/m² to 1000 g/m², depending on the performance criteria. The physical requirements and technical specifications for paving blocks are summarized in Table 2.

Table 2
Physical requirements for paving blocks.

S.No	CHARACTERISTICS	REQUIREMENT
1	Water absorption value, Maximum	7% (Individual) and 6% (Average)
2	Compressive strength in MPa, Minimum	fck – 3 (Individual and Average)
3	Abrasion resistance, Maximum	Dry: • Individual: 20000 mmc per 5000 mm2 • Average: 18000 mmc per 5000 mm2 Wet: • Individual: 22000 mmc per 5000 mm2 • Average: 20000 mmc per 5000 mm2
4	Tensile splitting strength, MPa, Minimum	a) Individual: 0.8 fck (for grades < M40)3 MPa (for grades > M40) b) Average: 0.085 fck (for grades < M40)3 MPa (for grades > M40)
5	Flexural strength, MPa, Mininimum	a) Individual: 0.10 fck b) Average: 0.11 fck

2.4. Hydraulic properties

Geo-textiles are engineered to facilitate water permeability while effectively retaining fine soil particles, making them suitable for filtration and drainage applications. They exhibit permeability coefficients typically ranging from 0.01 cm/s to 0.5 cm/s [³²], allowing adequate water flow through the material. Additionally, their effective pore size varies between 50 μm and 500 μm, which ensures efficient filtration performance without compromising drainage capacity [³³].

2.5. Durability

Geo-textiles exhibit excellent chemical resistance, maintaining their integrity when exposed to a wide range of substances, including acids and alkali, which enhances their suitability for diverse environmental conditions. High-quality geo-textiles are also treated for UV resistance, minimizing degradation from prolonged exposure to sunlight and thereby supporting long-term outdoor performance. Additionally, these materials demonstrate a broad temperature tolerance, withstanding conditions ranging from −40°C to 120°C, depending on the type of polymer used. These properties collectively contribute to the durability and reliability of geo-textiles in construction applications, including paver blocks.

2.6. Sustainability

Geo-textiles contribute to sustainable construction practices not only through their performance characteristics but also through their environmental benefits. They can be manufactured using recycled polymers, thereby reducing their overall environmental footprint. Moreover, their inherent durability and longevity minimize the need for frequent maintenance or replacement, further supporting long-term sustainability in infrastructure applications such as paver blocks.

3. PREPARATION OF PAVER BLOCKS - MANUFACTURING METHODS (PHASE - 1)

The manufacturing process of geo-textile fibre-reinforced paver blocks integrates geo-textile fibres (PP, PET, PE) into the conventional paver block production method. The fibres were manually cut into uniform strips. and used consistently across all sample batches. This inclusion ensures that the study methodology aligns with IS 15658’s emphasis on material characterization and repeatable performance and it enables accurate reproduction of results. The geotextile and polymer fibres were gradually introduced during the dry mixing phase, followed by thorough mixing with aggregates and cement for a minimum of two minutes before water and super plasticizer were added. This method ensured consistent dispersion and minimized clumping. Additionally, visual inspections were conducted during casting and post-curing fracture analysis revealed no signs of fibre clustering or void concentrations. While quantitative image-based fibre dispersion analysis was not performed in this study, the adopted mixing methodology aligns with best practices for ensuring homogeneity in fibre-reinforced concrete and complies with the uniformity principles.

3.1. Mix proportions

The mix consist of geo-textiles, sand and coarse aggregate. The first six samples are made using high dense polypropylene fibres (HDPPF), while the next three samples utilize High Dense Polyethylene Fibres (HDPEF) and the last three samples used High Tensile Polyester (HTPE) materials.

The first three GSC samples and PP samples maintained 20% coarse aggregate in a constant proportion. The subsequent three samples contain 10% of coarse aggregate in a constant proportion. The following three samples are made without coarse aggregate, maintaining a constant proportion of geo-textile and sand. The proportions of geo-textiles and sand in the paver blocks vary from 20% to 60%, with different ratios tested to determine the optimal combination. The samples of the paver blocks with different geo-textile fibres, sand and coarse aggregate are listed in Table 3.

Table 3
Mix proportions of paver block.

S.NO	SAMPLE	GEO-TEXTILE FIBRES (%)	SAND (%)	COARSE AGGREGATE (%)
1	GSC 1	50	30	20
2	GSC 2	40	40	20
3	GSC 3	30	50	20
4	GSC 4	50	40	10
5	GSC 5	45	45	10
6	GSC 6	40	50	10
7	GS 1	60	40	0
8	GS 2	50	50	0
9	GS 3	40	60	0
10	PP 1	50	30	20
11	PP 2	40	40	20
12	PP 3	30	50	20

3.2. Mould preparation

As the mixture is being prepared, the metal moulds with dimensions of 260 mm in length, 120 mm in width and 65 mm thickness with an aspect ratio of 4, ensuring consistency in compliance with the specifications outlined in IS 15658 are used to shape the paver blocks. The moulds are carefully cleaned and prepared. This process ensures that any leftover residue from prior batches is completely removed, as such remnants could compromise the shape, surface finish or overall quality of the new blocks. After cleaning, a light coat oil is applied to the inner surfaces of the mould. This serves as a release agent, preventing the mixture from adhering to the mould and facilitate the seamless removal of the hardened blocks [³⁴]. A proper mould preparation is an essential step to ensure uniformity and a hassle-free production process.

3.3. Pouring and compaction

After preparing the moulds, the geo-textile fibres, combined with sand and coarse aggregate, are poured into the mould. Compaction plays a vital role in the manufacturing process, as it ensures the material is tightly packed within the mould, minimizing internal pores and air voids that could otherwise compromise the strength and durability of the final product. The blocks are compacted using manual method to achieve the desired density and uniformity. Inadequate compaction can result in reduced strength and durability, as voids within the block may create structural weaknesses.

3.4. Drying/hardening and removal of mould

After the block has been thoroughly compacted, it is set aside to dry and harden. The paver blocks are left to dry in an open area for 24 hours, during which the material cools and solidifies, transitioning from its molten or semi-fluid state to a stable, solid form. This drying phase is crucial as it enables the block to achieve its initial hardness, ensuring it is stable enough for safe handling and any subsequent processing steps.

After the 24-hour drying period, the hardened paver block is gently removed from the mould. The oil applied during the mould preparation ensures a smooth release, preserving the block’s shape and surface finish. Each block is then inspected for defects, such as cracks, uneven surfaces, or signs of incomplete compaction. Once the block passes this quality check, it proceeds to further curing.

3.5. Final testing

After de-moulding, the samples were subjected to a series of tests to assess their strength and durability. The tests include evaluation of compressive strength, flexural strength, water absorption and fire resistance, to ensure that the blocks meet the necessary standards for construction use [³⁵, ³⁶]. The test results were optimized to evaluate the performance of the sample groups, including GSC, GS and PP. Subsequently, the relationship between compressive strength and flexural strength was analyzed. Furthermore, machine learning algorithms were employed to evaluate the actual and predicted compressive strengths based on the experimental data.

4. EXPERIMENTAL STUDY

4.1. Compressive strength test

The testing process was conducted in strict accordance with the ASTM C109/C109M standard [³⁷], an internationally recognized protocol for assessing the 28 days compressive strength of hydraulic cement mortars, though it can also be used for other materials such as paver blocks. Adhering to this standard ensures the accuracy, consistency and comparability of the results with other research and industry standards [³⁸]. To align with these established parameters, the Compression Testing Machine (CTM) was calibrated to apply pressure at a controlled rate of 20 MPa per second. This specific rate is essential for ensuring uniform stress distribution throughout the sample, thereby preventing any localized failure due to uneven pressure application. Each block was carefully positioned in the CTM’s testing chamber to ensure proper alignment, minimizing the risk of irregular load distribution that could skew the results.

The paver blocks were designed to replicate real-world conditions, allowing the testing process to offer valuable insights into their performance in practical applications. During the test, the machine progressively applied stress to the block until it reached its failure point, defined as the stage where the material could no longer withstand the applied load and fractured. This failure point was recorded as the material’s maximum compressive strength, which serves as a crucial measure of its load-bearing capacity. The data collected from these tests was used to evaluate the structural integrity of paver blocks made from geo-textile, comparing their performance with traditional paver blocks crafted from conventional materials. The minimum 28 days compressive strength requirement of paver blocks as prescribed by IS 15658: 2006 (Table 3) for any grade is calculated as follows,

(1) $$\mathrm{Compressive\; strength}\ge \mathrm{}{\mathrm{f}}_{\mathrm{ck}}\mathrm{}+0.825\times \mathrm{established\; standard\; deviation}(\mathrm{rounded\; off\; to\; nearest\; 0.5\; N}/\mathrm{m}{\mathrm{m}}^{\text{2}}\mathrm{})$$

4.2. Flexural strength test

The flexural strength test was performed following the ASTM C78/C78M standard [³⁹], a widely accepted procedure for assessing the flexural strength of concrete using a simple beam with third-point loading. This test, while designed for concrete, is also applicable to materials such as paver blocks. It is essential for evaluating how well the paver blocks can withstand bending forces, which they are likely to encounter in real-world environments, such as walkways or driveways. By adhering to the ASTM guidelines, the test ensures consistency, reliability and the ability to compare results with other studies and industry standards. For this test, the paver blocks were placed on two rollers to support the block, ensuring they were properly aligned to prevent uneven stress distribution. A load was then applied at two points along the top of the block, between the supports, inducing bending stress. This loading configuration allows for a uniform application of the force (6 kN/min), simulating real-life conditions where blocks might experience heavy loads or uneven surfaces. The load was progressively increased until the block reached failure, defined as the point where the block cracked or fractured due to excessive bending stress [⁴⁰].

The flexural strength, measured at failure, serves as a crucial indicator of the block’s resistance to tensile forces and its durability under stress. These results were used to assess the performance of paver blocks made from geo-textiles, comparing their flexural strength to that of traditional paver blocks. This data is vital for determining the potential applications of these innovative paver blocks, particularly in situations where resistance to bending is a key requirement.

4.3. Water absorption test

For paver blocks, water absorption test involves immersing the blocks in distilled water for 24 hours and measuring their weight before and after immersion. The dry weight (W₁) of the block is recorded initially, and after 24 hours, the block is removed, surface-dried and reweighed to obtain the wet weight (W₂). The water absorption percentage is then calculated using the formula:

(2) $${{{\text{Water Absorption (\%) = [(W}}_{\text{2}}\text{– W}}_{\text{1}}\text{) / W}}_{\text{1}}\text{] × 100}$$

This calculation provides the percentage of water absorbed by the paver block, which is an important indicator of its ability to withstand environmental conditions and its overall durability. The lower the water absorption, the more resistant the paver block is to water, enhancing its performance in outdoor settings.

4.4. Fire resistance test

For paver blocks, fire resistance test evaluates their ability to withstand high temperatures and maintain structural integrity when exposed to fire, making it essential for determining their suitability in fire-prone areas or industrial environments. To conduct this test, representative samples of paver blocks are selected, cleaned and dried in an oven at 105°C for 24 hours to eliminate any moisture, as residual water can impact the results. After cooling the blocks to room temperature, they are placed in a furnace or kiln, where the temperature is gradually increased to the desired level, typically ranging from 600°C to 1200°C, depending on the testing requirements. The blocks are exposed to this temperature for a specified duration, simulating real-life fire conditions. During the test, the blocks are monitored for visible signs of cracking, spalling or deformation. After the heating phase, the blocks are allowed to cool naturally and their post-fire condition is assessed, including any changes in weight, strength or physical appearance [⁴¹].

The results provide insights into the fire resistance and thermal stability of the paver blocks, which are critical parameters for ensuring their performance and safety in applications where exposure to high temperatures is a concern. Blocks with higher fibre content tend to degrade more rapidly under fire exposure due to the lower melting point of fibres, which can cause warping, melting, or loss of structural integrity. In comparison, blocks with reduced fibre content and higher proportions of sand and aggregate are generally more fire-resistant, as these non-combustible materials act as insulators, reducing heat penetration and enhancing the block’s ability to withstand high temperatures.

While the presence of fibres can limit the overall fire resistance of the blocks, optimizing the material composition, such as adjusting the fibre-to-aggregate ratio or incorporating fire retardant additives, can significantly improve their performance and make them more suitable for applications requiring enhanced fire resistance.

5. RESULTS AND DISCUSSION

Workability of the mixes was evaluated prior to the mechanical and durability tests using the standard slump test. The slump values were observed to be in the range between 30 mm to 100 mm across different mix compositions incorporating Polycarboxylate Ether (PCE) as super plasticizer, indicating adequate flow characteristics for casting while maintaining low water-to-cement ratios.

5.1. Compressive strength

By incorporating geo-textile fibres into concrete, the different types of mould were casted using varying proportions of geo-textile fibres (GTF) sand along with different percentages of coarse aggregate. Initially, a concrete mix with 20% coarse aggregate and 50%, 40% and 30% geo-textile fibre combined with 30%, 40% and 50% sand was used. Subsequently, another mix with 10% coarse aggregate and 50%, 45% and 40% geo-textile combined with 40%, 45% and 50% sand was used.

Following that, a mix with 0% coarse aggregate and 60%, 50% and 40% geo-textile combined with 40%, 50% and 60% sand was used. Lastly, a mix using polypropylene, with 50%, 40% and 30% geo-textile combined with 30%, 40% and 50% sand, was utilized. For each sample, three specimens were tested and the average value was reported. A total of 36 specimens were tested. Table 4 listed the corresponding compressive strength results of various samples.

Table 4
Compressive strength values of paver blocks.

S.NO	SAMPLE	COMPRESSIVE STRENGTH (N/mm2)	MEAN (N/mm2)	STANDARD DEVIATION (N/mm2)
1	GSC 1	30	27.27	5.37
2	GSC 2	36
3	GSC 3	21.66
4	GSC 4	25.3
5	GSC 5	28.33
6	GSC 6	22.34
7	GS 1	26.53	23.51	3.98
8	GS 2	25
9	GS 3	19
10	PP 1	16	16.67	1.15
11	PP 2	16
12	PP 3	18

Figure 2 illustrates the comparative analysis of compressive strength of various samples. Among the samples, GSC 2, GSC 1 and GSC 5 shows superior compressive strength, indicating that a balanced combination of geotextile fibre (40–45%), sand (45–50%) and aggregate (10–20%) contributes positively to structural performance. In contrast, mixes with excessively high fibre content, such as GS 1 (60%) or low aggregate content, such as GS series (0%), demonstrated reduced strength, highlighting the importance of optimal proportioning. Sand content, which ranged from 30% to 60%, also played a significant role, where overly high amounts potentially diminished strength due to reduced paste availability for bonding.

Figure 2
Compressive strength of paver block for different samples.

Additionally, the presence of coarse aggregates in the range of 10 to 20% was associated with improved strength, as seen in the GSC and PP series, suggesting their critical role in load distribution and internal structure. Overall, the data underscore the necessity of carefully optimizing the mix design to achieve enhanced compressive performance in geotextile fibre-reinforced paver blocks, supporting their potential in durable pedestrian applications. The results of predicted compressive strength is shown in Figure 3.

Figure 3
Results of predicted compressive strength of samples.

The data highlights the importance of optimizing material proportions to achieve enhanced compressive strength and overall durability in paver block manufacturing. The values of the predicted compressive strength (in Figure 4) of the samples with Machine Learning findings are listed as follows,

Figure 4
Actual and Predicted compressive strength of paver blocks.

• Mean Squared Error (MSE): 182.70817992251213

• R-squared (R²) Score: −3.1948306614862476

• Model Coefficients: [ 0.20592987 -0.3968898 0.19095993]

• Model Intercept: 32.70764116575593

• Predicted Compressive Strengths for New Samples: [32.05224044 25.87434426]

The results reveal that geotextile fiber content exhibits a slight positive correlation with compressive strength, suggesting that fiber inclusion enhances the ductility and crack-bridging ability of the matrix, thereby improving mechanical performance.

In contrast, sand content shows a marginal negative trend, indicating that excessive sand may disrupt particle interlocking and reduce the structural integrity of the paver blocks. Aggregate content, however, displays minimal sensitivity to changes in compressive strength, as evidenced by the nearly flat trend line, implying that its effect remains neutral within the experimental range.

Overall, the trend lines indicate that geotextile fiber has a more pronounced influence on strength enhancement compared to sand and aggregate, though the observed scatter suggests that additional factors, such as material dispersion and compaction quality, may also play a role.

5.1.1. Coefficient of variation (CV) of compressive strength

To evaluate the consistency of the results, CV was computed for each sample by calculating the ratio of standard deviation to the mean value (in %) for each samples. The results of the CV shows that PP group showed the least value of 6.9%, indicating high uniformity but insufficient strength performance. Conversely, GSC & GS group exhibited a higher value of 9.7% & 8.92%, suggesting increased variability attributable to its heterogeneous aggregate composition. The CV results underscores the significant impact of fibres in various compositions and falls within the acceptable limit. Therefore, it is suitable for paving applications.

5.2. Flexural strength

The samples were prepared with different compositions, to assess the flexural strength of the paver blocks. Table 5 represents the results of flexural strength for various samples. Among these, sample GSC 2 exhibited the highest value of 7.1 N/mm². In general, samples with higher fibre content, such as GS 1 and GS 2, demonstrated comparatively high flexural strengths of 5.4 N/mm² and 6.1 N/mm², respectively, highlighting the beneficial effect of fibres content up to a certain limit.

Table 5
Flexural strength values of paver blocks.

S.NO	SAMPLE	FLEXURAL STRENGTH (N/mm2)	MEAN (N/mm2)	STANDARD DEVIATION (N/mm2)
1	GSC 1	6	5.45	1.21
2	GSC 2	7.1
3	GSC 3	4.5
4	GSC 4	5.2
5	GSC 5	6
6	GSC 6	3.9
7	GS 1	5.4	5.23	0.93
8	GS 2	6.1
9	GS 3	4.2
10	PP 1	4.3	4.27	0.735
11	PP 2	5.1
12	PP 3	3.4

From the graph as shown in Figure 5, it is observed that the flexural strength (dotted red line) varies across the samples, with GSC 2 exhibiting the highest flexural strength. This trend suggests that the inclusion of geo-textile fibres positively influences the flexural strength up to a certain percentage, highlighting their potential as a reinforcement material in paver blocks. The values of the predicted flexural strength (in Figure 6) of the samples with Machine Learning findings are listed as follows,

Figure 5
Flexural strength of paver block for different samples.

Figure 6
Results of predicted flexural strength of samples.

• Mean Squared Error (MSE): 2.296304532831678

• R-squared (R²) Score: −3.7619218422776726

• Model Coefficients: [0.04857923–0.0663388 0.01775956]

• Model Intercept: 5.96584699453552

• Predicted Flexural Strengths for New Samples: [6.49344262−5.03606557]

Figure 7, illustrates the relationship between flexural strength (N/mm²) and the material composition parameters — geotextile fiber content, sand content and aggregate content - through actual and predicted values. The first plot shows a slight positive correlation between geotextile fiber content and flexural strength, indicating that higher fiber content tends to enhance the structural performance of paver blocks. In contrast, the second plot reveals a negative correlation between sand content and flexural strength, suggesting that an increased sand proportion may reduce overall strength due to weaker inter-particle bonding. The third plot demonstrates that aggregate content remains relatively constant across varying flexural strengths, as indicated by the nearly horizontal trend line. Overall, the predicted regression lines align closely with the experimental data, confirming the model’s ability to reasonably capture the material behavior trends despite some scatter in individual observations.

Figure 7
Actual and predicted flexural strength of paver blocks.

Overall, the regression model performs effectively in predicting material components, with Geo-textile Fibre predictions showing the closest alignment to actual data, while predictions for Sand and Aggregate exhibit higher variability, suggesting potential areas for model improvement. The load-deflection behavior of various paver block specimens, as shown in Figure 8, highlights the influence of material composition on structural response under a uniform loading rate.

Figure 8
Load-deflection curve.

All tested samples exhibited an initial linear elastic response, followed by distinct variations in post-elastic deflection behavior. GSC samples, notably GSC 2 and GSC 6, demonstrated higher stiffness combined with moderate brittleness, whereas GSC 3 exhibited increased ductility. The GS series showed moderate deflection capacities, with GS 3 attaining a peak deflection of 2.2 mm, indicative of superior energy absorption characteristics. The PP series, particularly PP 3, recorded the maximum deflection of 3.0 mm, highlighting the significant improvement in ductility due to the incorporation of polypropylene fiber reinforcement.

5.2.1. Coefficient of variation of flexural strength

The consistency of the flexural strength values was evaluated using the coefficient of variation (CV). The GSC group exhibited the highest average value of 5.45 N/mm² with a CV of 12.20%, followed by the GS group (5.23 N/mm², CV: 13.78%) and the PP group (4.27 N/mm², CV: 15.21%). All groups met the expected flexural strength for paving applications such as non-traffic and light traffic conditions. However, the higher CV values suggest moderate variability across all groups, which may be attributed to the random orientation or non-uniform dispersion of fibres during mixing and casting.

5.3. Water absorption

The paver blocks were cured by immersing them in water for 24 hours after casting. Their wet weight, denoted as W₂, was then measured. Following this, the blocks were dried in an oven at a specific temperature for 24 hours and their dry weight, denoted as W₁, was recorded. The water absorption percentage was calculated to ensure it remained within the permissible limit of 7% of the paver block’s weight. The water absorption value for different samples of paver blocks are listed in Table 6.

Table 6
Water absorption values of different samples.

S.NO	SAMPLE	WATER ABSORPTION VALUE
1	GSC	6.0
2	GS	5.63
3	PP	4.24

The water absorption values as shown in Figure 9 were 6.1% for GSC, 5.63% for GS and 4.24% for PP, indicating varying degrees of moisture uptake among the samples. PP demonstrated the lowest absorption, suggesting superior water resistance due to its denser and less porous structure, which enhances durability in moisture-prone environments. In contrast, GSC exhibited the highest absorption, while GS showed intermediate performance. Despite these differences, all values fall within acceptable limits, confirming the suitability of GSC, GS and PP for paving applications. These results highlight the influence of material composition, particularly the type of geo-textile fibre used, on the water absorption behavior of paver blocks.

Figure 9
Water absorption value.

5.4. Fire resistance

This test is necessary to evaluate the dimensional changes in the sample, as it contains fibres that are more susceptible to fire. The testing process involves placing the paver block in an oven set to a controlled temperature of 750°C for one hour to ensure thorough heat exposure. After the heating period, the dimensions of the block are measured to detect any changes caused by the heat. If the dimensional change is within the acceptable limit of 100 mm, the block is considered suitable for construction, signifying that its structural integrity remains intact. In this case, as the dimensional change is less than 100 mm, the block satisfies the required criteria and is deemed appropriate for site work. This assessment ensures that the paver blocks are both durable and safe, particularly for applications where fire resistance is crucial. The details of the thermal limits of the polymers during the assessment are mentioned in Table 7.

Table 7
Thermal limits of polymers.

POLYMER	MELTING POINT	DECOMPOSITION TEMPERATURE	MAXIMUM SERVICE TEMPERATURE	REMARKS
PP	160°C–170°C	300°C–350°C	90°C–110°C	Softens quickly under heat
PET	250°C–260°C	400°C–450°C	120°C–150°C	More thermally stable than PP/PE
PE	110°C–130°C	300°C–350°C	80°C–100°C	Low melting point

5.5. Comparative strength analysis of conventional and fibre-modified paver blocks

According to IS 15658:2006, concrete blocks of M30/M35 grade are typically expected to achieve:

• Compressive strength test: GSC 2 exhibits a higher compressive strength of 36 N/mm², surpassing the conventional range of ≥30–35 N/mm². for light traffic conditions and suitable for light traffic flow.

• Flexural strength test: ≈ 4.0 to 5.0 N/mm² (typical for M30–M35 grade mixes) - In the present study, several modified mixes exceeded this benchmark. The GSC series achieved the highest flexural strength, with GSC 2 reaching 7.1 N/mm², indicating improved post-cracking resistance likely due to the combined effects of fibre and aggregate interaction. The GS series also showed strong performance, with GS 2 recording up to 6.1 N/mm², demonstrating that fibre reinforcement alone can significantly enhance flexural strength even without coarse aggregates. The PP series recorded flexural strengths between 3.4 and 5.1 N/mm², with PP2 (5.1 N/mm²) and PP1 (4.3 N/mm²) meeting or slightly exceeding the minimum requirement for M30-grade blocks.

• Water absorption test: According to the specified requirements, water absorption should not exceed 7% by weight. The experimental results confirm that all samples fall within this prescribed limit. The water absorption values, in descending order, are: PP < GS < GSC.

• Fire resistance: Dimensional change – <100 mm. The results indicate that the dimensional change in all samples remained below 100 mm, suggesting adequate thermal stability and the ability to withstand a range of temperature variations.

5.6. Influence of fibre on compressive and flexural strength in concrete

While the peak compressive strength (36 N/mm² for GSC 2) represents the material’s capacity to resist axial loads, the flexural strength (7.1 N/mm² for GSC 2) primarily measures the material’s ability to resist bending stresses, which are influenced by the fibre reinforcement. As fibres, particularly geotextile fibres, generally enhance the post-peak behavior of concrete by improving crack control and energy dissipation, they tend to increase flexural strength more significantly than compressive strength. This is because fibres provide additional resistance to cracking, especially under tensile stresses, which are more pronounced in bending than in axial compression. The increased flexural strength observed in the GSC series (7.1 N/mm² for GSC 2) can thus be attributed to the fibres ability to bridge cracks and enhance the material’s performance under bending, whereas the compressive strength is more directly influenced by the cementitious properties and aggregate content. These findings are consistent with previous research on fibre-reinforced concrete, which suggests that while fibres improve post-crack behavior, they may not significantly impact the material’s peak compressive strength.

5.7. Relationship between fibre content and porosity

The influence of geotextile fiber content on the porosity of paver blocks was examined through the analysis of experimental data from three sample groups: GSC, GS and PP. A quadratic regression model was fitted to simulated porosity values based on fibre content for each group.

Figure 10 shows the relationship between geo-textile fibre content and porosity in paver blocks. The GSC group exhibited a clear U-shaped relationship between fibre content and porosity. The porosity decreased as the fibre content increased from 30% to 40%, reaching a minimum around 40%. Beyond this point, further increases in fibre content led to higher porosity. This suggests that excessive fibre content may disrupt particle packing or hinder proper compaction, resulting in increased voids. In the GS group, the trend was similar but less pronounced. The porosity was lowest around 47%–50% fibre content. The fewer data points in this group limit the certainty of the optimal range, but the general quadratic behavior reinforces the presence of an optimum fibre content beyond which porosity begins to increase. The PP group, which also demonstrated the lowest water absorption (4.24%), showed a strong U-shaped curve with the minimum porosity occurring near 40% fibre content. This supports the hypothesis that PP fibres effectively reduce porosity at moderate content levels, but may cause void formation if overused. Across all groups, a quadratic relationship was observed, highlighting the presence of an optimal fibre content that minimizes porosity. For the GSC and PP groups, this optimum lies around 40%, while the GS group suggests a slightly higher optimum near 47% to 50%. These findings are critical for optimizing paver block mix designs, balancing workability and durability while minimizing water permeability.

Figure 10
Relationship between fibre content and porosity.

6. SMART MATERIALS FOR STATION COMPONENTS (PHASE - 2)

Integrating eco-friendly paver blocks reinforced with geotextiles for pedestrian footpaths, alongside smart materials for bus station infrastructure, offers a comprehensive strategy for sustainable urban development. Regarding this invention, the study conducted field investigations at bus stations in India and collected information about the difficulties in station operations, focusing on the quality of station components concerning materials and structures. The study locations include Erode, Trichy, Tirupur, Pondicherry, Madurai Arapalayam, Madurai Mattuthavani, Salem, Namakkal, Coimbatore and Karur bus stations. Figure 11 shows the glimpses of field investigations at Coimbatore bus station.

Figure 11
Site investigation analysis with stakeholders using bus station at Coimbatore.

It was observed that conventional materials often exhibit short-term durability, necessitating frequent maintenance. The factor observed from the stakeholders during site investigation are as follows:

• Building materials: Compressive and flexural strength, durability against spillage of oil, diesel and other chemicals, resistance to abrasion and surface wear, temperature resistance, permeability control and sustainability as well as recyclability.

• Pavement quality factors: High load bearing capacity, fatigue resistance, surface skid resistance, rutting, deformation, thermal crack, drainage efficiency, freezing / thawing, noise and reflection.

• Parking pavement factors: Static load resistance, impact resistance, surface marking durability, maintenance, eco-friendly surface options, heat resistance and UV stability.

To address the persistent challenges in station infrastructure, this research synthesizes insights from diverse literature sources and industry-specific studies to propose suitable material alternatives for key station components. The specifications were developed targeting improvements in pavement quality, building infrastructure and provisions for parking and pedestrian zones, thereby facilitating smoother traffic flow and reducing maintenance requirements within station environments. The integration of smart materials, such as solar-powered systems, recycled construction components, and permeable surfaces, serves to enhance energy efficiency, lower carbon emissions and elevate the overall user experience. This holistic strategy simultaneously mitigates infrastructure maintenance issues and supports broader objectives of environmental sustainability and resource optimization. Emphasizing materials that combine durability with sustainability fosters the creation of resilient, adaptive and user-centered public spaces responsive to the evolving demands of urban populations.

Smart materials are increasingly pivotal in transforming bus station design by advancing sustainability, operational efficiency and user-eccentricity [⁴²]. Engineered to respond dynamically to environmental stimuli, these materials significantly improve energy performance and functional adaptability [⁴³, ⁴⁴]. Sustainable construction practices now prioritize the use of recycled plastics, rubber and bio-based composites such as bamboo and cork to curtail the carbon footprint. Furthermore, smart materials contribute to efficient water management through innovations like porous pavements and advanced drainage systems, effectively controlling stormwater runoff, reducing flood risks and enhancing groundwater recharge [⁴⁵]. Beyond environmental considerations, smart materials greatly enhance accessibility and inclusivity within public transport infrastructure. Implementations such as tactile paving, textured surfaces, smart signage and auditory guidance systems enable independent navigation for visually impaired and differently-abled individuals. Integration with IoT technologies further augments operational performance through real-time monitoring of environmental parameters – including temperature, humidity, air quality and pedestrian flow via embedded sensor networks [⁴⁶, ⁴⁷]. This data-driven management approach improves facility maintenance regimes, optimizes energy use and enhances passenger comfort and safety. Looking forward, rapid advances in material science and nanotechnology are poised to catalyze the development of next-generation smart materials characterized by superior durability, adaptability and multi-functionality. Emerging materials like graphene exhibit significant promise for applications in energy storage, structural reinforcement and environmental sensing, thereby reinforcing infrastructure resilience and promoting sustainable urban development. As smart city initiatives expand globally, the integration of these advanced materials will play a central role in transforming bus stations into intelligent, environmentally responsible and user-oriented transit hubs. Consequently, the adoption of smart materials represents a critical evolution in the design, construction and operational paradigms of modern public transportation facilities, ensuring alignment with contemporary technological advancements and environmental imperatives.

6.1. Energy harvesting materials

Piezoelectric materials can be incorporated into flooring systems at bus stations to harness mechanical energy generated by foot traffic and convert it into electrical energy. This harvested energy can then be utilized to power various systems within the station, including LED lighting, digital displays and charging stations for electronic devices. The integration of piezoelectric technologies not only decreases dependence on external power sources but also encourages the adoption of renewable energy solutions, thereby supporting global sustainability goals. This innovative approach underscores the potential of smart materials in advancing energy-efficient and environmental friendly public infrastructure.

6.2. Phase change materials (PCM’s)

PCM’s can absorb, store and release thermal energy, thereby playing a crucial role in regulating indoor temperatures. By integrating PCMs into walls, ceilings or flooring, bus stations can maintain a more consistent indoor climate, which reduces the reliance on artificial heating and cooling systems. This not only enhances passenger comfort but also significantly decreases energy consumption and operational costs. Additionally, the use of electrochromic glass in bus station design highlights the potential of smart materials to improve energy efficiency and comfort. Electrochromic glass can alter its tint in response to electrical signals, enabling dynamic control over the amount of natural light and heat entering the building. This feature helps minimize glare, reduces the load on air conditioning systems and maintains a comfortable indoor environment, regardless of external weather conditions. The incorporation of such smart materials demonstrates a commitment to sustainability and operational efficiency in public transport infrastructure.

6.3. Energy efficient materials

These materials play a crucial role in maintaining cleanliness and hygiene in bus stations. Self-cleaning surfaces, coated with photo-catalytic materials like titanium dioxide, can break down organic pollutants and prevent the accumulation of grime. When exposed to sunlight, these coatings catalyze a reaction that decomposes organic matter and pollutants, making it easier to clean surfaces and reducing the frequency and cost of maintenance. Hydrophobic and oleophobic coatings, which repel water and oil, are also increasingly used in public transport facilities [⁴⁸]. These coatings protect surfaces from moisture and contaminants, preventing the growth of mold and bacteria and ensuring a more hygienic environment for passengers. Moreover, the use of antimicrobial materials is becoming more prevalent in bus station construction, particularly in high-touch areas such as ticket counters, handrails and seating. These materials are treated with antimicrobial agents that inhibit the growth of bacteria, viruses and fungi, thereby enhancing public health safety, especially in densely populated areas. The incorporation of smart materials extends to the structural elements of bus stations as well. Shape-memory alloys and smart composites can be used in the construction of load-bearing structures. These materials can return to their original shape after deformation, providing enhanced durability and resilience against environmental stresses such as earthquakes or wind. This property is particularly valuable in ensuring the longevity and safety of public infrastructure [⁴⁹].

6.4. Other materials

In addition to their applications in structural and surface enhancements, smart materials are being increasingly utilized to improve the functionality of bus station amenities. For example, interactive LED flooring systems can display dynamic information, such as bus schedules, emergency alerts and way finding directions. These systems offer a visually engaging and versatile platform for communication and navigation within the station, enhancing passenger experience and safety. Furthermore, the integration of smart textiles in seating and other soft furnishings significantly improves passenger comfort and experience. These textiles can be embedded with sensors to monitor environmental conditions, allowing for automatic adjustment of properties such as temperature and firmness for optimal comfort. Additionally, smart textiles can provide innovative features like charging capabilities for personal electronic devices, further enhancing convenience for passengers. This integration of smart materials into bus station amenities represents a forward-thinking approach to public transport infrastructure, prioritizing both functionality and user experience [⁵⁰].

7. APPLICATIONS

The materials used for various station components, along with their properties and typical applications, are detailed in Table 8 corresponding to energy harvesting materials, phase change materials and energy-efficient materials, respectively.

Table 8
Applications and functions.

S.NO	SMART MATERIAL	ENERGY TYPE	TYPICAL APPLICATIONS IN BUS STATION
1	Photovoltaic (PV) Glass [51]	Solar	Transparent roofing or canopy panels for harvesting solar energy while providing shelter
2	Building-Integrated PV (BIPV) [51]	Solar	Facades, side panels, or rooftops integrated with solar cells to power lights and displays
3	Thermo electric Materials (e.g., Bi₂Te₃) [52]	Heat gradient	Platform/floor tiles that generate electricity from foot traffic to power lighting or display boards
4	Piezoelectric Materials (e.g., PVDF, PZT) [52]	Mechanical pressure	Mounted near engine exhausts or mechanical rooms to convert waste heat into electricity
5	Triboelectric Nanogenerators [52]	Mechanical vibration	Installed in handrails, ticket counters or entrance gates to harvest energy from motion
6	Phase Change Materials (PCMs) [53]	Thermal regulation	Integrated into wall panels or roofs to passively regulate interior temperatures
7	Electrochromic Glass [54]	Solar control	Smart windows that adjust tint based on sunlight, reducing glare and energy use
8	Thermo chromic Coatings [54]	Temperature-responsive	Applied to shelters or benches to reduce heat absorption during peak temperature
9	Photo-luminescent Tiles or Paints [55]	Light storage/emission	Used for safety signage, step markers, or platform edges that glow in low-light conditions
10	Solar Paint (Perovskite) [51]	Solar	Applied to outer walls or roof structures to harvest solar energy in a lightweight form
11	Energy-Harvesting Concrete [52]	Mechanical	Pavement slabs that generate power from the weight of buses or pedestrian footfall
12	Graphene Coatings [56]	Thermal/Electrical	Coated on panels or wiring areas for heat dissipation and electrical enhancement
13	Hydrogel-Based Facades	Passive cooling	Cooling screens on facades to regulate temperature via evaporative cooling
14	Smart Roof Tiles [54]	Solar	Rooftop installations to produce energy while maintaining architectural appearance
15	Self-Cleaning TiO2 Nano-Coatings	UV-activated	Applied to glass panels and roofs to reduce maintenance by repelling dust/water
16	Wind-Responsive Shading Panels	Kinetic	Adjustable facades or louvers that move with wind to regulate sunlight and airflow
17	Transparent Solar Coatings [55]	Solar	Applied on waiting area glass for daylight harvesting while maintaining visibility
18	RF/EM Harvesters [54]	Electromagnetic	Mounted near digital display boards or surveillance systems to capture ambient EM energy
19	Bio-Photovoltaic Walls (experimental)	Organic solar	Vertical green walls with integrated solar microbial panels for Eco-aesthetic energy use
20	Thermal Conductive Polymers [52]	Heat distribution	Used in electrical housings and beneath seating to distribute heat or insulate power systems
21	Paraffin Wax (n-Octadecane, etc.) [53]	Solid–Liquid	Roof insulation panels, ceiling tiles
22	Lauric Acid [55]	Solid–Liquid	Wall boards and seating insulation
23	Polyethylene Glycol (PEG) [54]	Solid–Solid or Solid–Liquid	Wallboard integration, flooring
24	Hydrated Salt (e.g., Glauber’s Salt – Na₂SO₄·10H₂O)	Solid–Liquid	Embedded in wall or roof panels
25	Calcium Chloride Hexahydrate (CaCl2·6H2O) [54]	Solid–Liquid	Air handling units, wallboards
26	Erythritol	Solid–Liquid	High-temp HVAC systems, solar storage walls
27	Capric–Lauric Acid Mixtures	Solid–Liquid	Panels in waiting areas, canopy systems
28	Butyl Stearate	Solid–Liquid	Underfloor thermal storage layers
29	Stearic Acid	Solid–Liquid	Embedded in curtain walls for heat buffering
30	Myristic Acid [56]	Solid–Liquid	Used in PCM panels behind cladding
31	Microencapsulated PCMs (Paraffin/Salt hydrates)	Encapsulated	Integrated into concrete panels, paint coatings
32	Rubitherm RT Series (RT21, RT25, RT27, etc.)	Commercial PCM	Roof decks, HVAC - integrated surfaces
33	ClimSel C Series (Salt Hydrates) [56]	Solid–Liquid	PCM bricks or plaster boards in waiting lounges
34	SP-25 A8 (Microtek Labs)	Micro encapsulated	Paints, coatings on walls or benches
35	Sunamp PCM Heat Batteries	Solid–Solid	Thermal storage units for night use
36	BioPCM™ (Phase Change Energy Solutions) [56]	Organic	Behind signage or inside walls
37	PCM-TES (Thermal Energy Storage) Panels	Composite Panels	Roof and wall retrofits
38	EnerStore by Croda [54]	Bio-based	Sustainable design elements
39	RT Pure Series (Enhanced organic) [56]	Solid–Liquid	Under roofing or skylight zones
40	Encapsulated Salt Hydrate Mats [54]	Flexible sheets	Partition walls or waiting zone ceilings
41	Aerogel Insulation	Ultra-low thermal conductivity, lightweight	Wall and ceiling insulation, thermal breaks
42	Vacuum Insulated Panels (VIPs)	Very high R-value in compact form	Prefab walls, modular terminal panels
43	Low-E Glass [52, 56]	Reflects infrared heat, maintains visible light	Windows, skylights, façades
44	Cool Roof Coatings [56]	High solar reflectance, lowers roof temperature	Terminal rooftops, canopy structures
45	Smart Thermo chromic Windows [56]	Changes transparency with temperature	Waiting lounges, facade glazing
46	Electrochromic glass	Switchable tint via electric signal	Control rooms, admin office partitions
47	Phase Change Drywall [56]	Thermal energy storage, maintains interior temp	Interior partitions, walls
48	Reflective Insulation (Foil-based)	Reduces radiant heat transfer	Roofs, attics, shelters
49	Insulating Concrete Forms (ICFs)	Thermal mass + insulation	Structural walls of stations
50	Structural Insulated Panels (SIPs) [56]	Pre-insulated panels with high efficiency	Waiting bays, restrooms, admin areas
51	Green Roof Systems	Natural insulation, absorbs heat	Terminal rooftops, bus bays
52	Double or Triple Glazed Windows [56]	Improves thermal barrier, reduces HVAC load	Ticketing counters, offices
53	LED-Embedded Flooring	Low power, directional lighting	Pathways, visual cues for pedestrian flow
54	Cork Insulation Panels	Renewable, natural thermal insulator	Acoustic and thermal insulation in walls
55	Hempcrete[56]	Breathable, low conductivity, eco-friendly	Wall infill, partitions
56	Recycled Denim Insulation	Non-toxic, good thermal and acoustic insulation	Utility rooms, low-traffic areas
57	High-Performance Glazing [56]	Low U-value, high SHGC control	Curtain walls, clerestory windows
58	Smart Paint (Thermo-Insulating)	Reflects or stores heat based on conditions	Walls, rooftops, facades
59	Translucent Insulation Materials (TIMs) [54]	Allows daylight, reduces heat loss	Day lighting panels, roof glazing
60	Concrete with Embedded PCM [56]	Enhances thermal performance	Floors and walls exposed to sunlight

8. CONCLUSION

The outcomes of this research provide a strong foundation for promoting the use of eco-friendly paver blocks in bus station infrastructure, demonstrating notable improvements in performance, cost-efficiency and sustainability. Also, the incorporation of smart materials further enhances durability under diverse environmental conditions, supporting long-term reductions in maintenance and aligning with sustainable construction practices. The key findings are summarized below:

• The integration of geotextile fibres significantly enhances the mechanical strength and durability of paver blocks, outperforming traditional compositions and contributing to improved structural performance.

• The proposed method reduces reliance on conventional raw materials such as coarse aggregate, fine aggregate and cement, thereby conserving natural resources and promoting sustainable construction.

• The partial replacement of coarse aggregate and sand with geotextile fibres results in reduced production costs, offering more economical and environmentally responsible approach to paver block manufacturing.

• The GSC 2 mix, composed of 40% geotextile fibres, 40% sand and 20% coarse aggregate, achieved a compressive strength of 36 N/mm² - well above the minimum 30 N/mm² required for non-traffic applications. This validates the proposed mix’s ability to withstand axial loads effectively.

• The flexural strength testing revealed that the GSC 2 sample also achieved the highest value of 7.1 N/mm², underscoring the importance of optimizing mix ratios to improve bending resistance and structural reliability.

• Water absorption tests indicated that all samples met acceptable standards, with the trend observed as PP < GS < GSC. The analysis of porosity values indicates that samples containing 40% fibre content in the GSC and PP groups, as well as those with 47–50% fibre content in the GS group, demonstrate suitability for practical applications.

• Fire resistance testing showed dimensional changes of less than 100 mm, meeting required thresholds for site applications. The fire resistance is attributed to the presence of silicon, magnesium and iron oxides in the sand, which offer thermal stability.

• The study highlights the comprehensive use of advanced materials such as energy-harvesting systems, phase change materials and energy-efficient composites in enhancing the safety, sustainability and inclusivity of bus station infrastructure.

• Smart materials enhance not only operational functionality but also user comfort and accessibility. With ongoing advancements in materials science, the integration of these technologies offers substantial potential to transform public infrastructure, addressing the challenges of urbanization, promoting environmental sustainability and meeting the complex needs of contemporary urban populations.

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Publication Dates

• Publication in this collection
  09 June 2025
• Date of issue
  2025

History

• Received
  28 Jan 2025
• Accepted
  13 May 2025