Lightweight concrete with coarse aggregate from ceramic waste at high temperatures

PASSOS, L.; MORENO Jr., A. L.; SOUZA, A. A. A.

doi:10.1590/S1983-41952020000200012

Abstract

With the increasing use of recycled materials from civil construction, mainly as substitute for some aggregates in concrete mixtures, it is necessary to obtain technical information on the performance of these new mixtures. National and international research on the use of ceramic waste in concrete production highlight good results of this new material’s mechanical performance in environmental situations. However, little is known about its behavior at high temperatures. In this context, we sought to verify the performance of concrete mixtures produced with aggregates from ceramic block waste at high temperatures, with evaluation of their residual mechanical strength, axial compressive strength and elastic modulus, and also their tendency to spalling in fire situations. The RILEM-129 MHT method [¹[1] RILEM TC 129-MHT. Recommendation of RILEM TC 129-MHT: Test Methods for Mechanical Properties of Concrete at High Temperatures - Compressive strength for service and accident conditions, V.28, p. 410-414, 1995.] was used for the assessment of residual mechanical strength, and the tendency to spalling was evaluated according to the procedure suggested by Souza and Moreno [²[2] SOUZA, A.A.A; MORENO JR., A.L. Proposta de avaliação em laboratório do lascamento explosivo do concreto em situação de incêndio. Concreto & Construção, v. 4, p. 96-103, 2010.]. In both these evaluations, there is no national standard, and, in the case of spalling, not even an international standard. Three concrete mixtures were used, one prepared with natural coarse basalt aggregate (reference) and the other two by replacing part of this natural aggregate with aggregate from ceramic block waste (40% and 100% of substitution in volume). In the end, it is concluded that the substitution of natural coarse aggregate for lightweight aggregate from ceramic block waste can be an excellent alternative to increase the resistance of concrete to fire. Thus, the results of mechanical strength and spalling in a fire situation, unprecedented in our country, can greatly support the decision-making about the use of this alternative material in the national construction industry.

Keywords:
concrete; waste; dosage; fire

Mixture	Cement (kg)	Natural fine aggregate (kg)	Natural coarse aggregate (liters)	Ceramic coarse aggregate (liters)	w/c	Slump (mm)
REF	1	2	1.7	0	0.49	50
S40	1	2	1.0	0.7	0.49	50
S100	1	2	0	1.7	0.49	50

Property	Ceramic waste aggregate	Conventional coarse aggregate	Fine aggregate
Bulk specific gravity (g/cm³) NBR NM 53 [³⁵[35] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR NM 53: Agregado graúdo -Determinação da massa específica, massa específica aparente e absorção de água. Rio de Janeiro, jul. 2003.], NM 52 [³⁶[36] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR NM 52: Agregado miúdo. -Determinação da massa específica e massa específica aparente. Rio de Janeiro, jul. 2002.]	1.77	2.89	2.63
C.M.D. (mm) NBR NM 248 [³⁹[39] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR NM 248: Agregados. Determinação da composição granulométrica. Rio de Janeiro, jul. 2003.]	19	19	4.8
F.M. (mm) NBR NM - 248 [³⁹[39] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR NM 248: Agregados. Determinação da composição granulométrica. Rio de Janeiro, jul. 2003.]	6.41	6.86	2.4
Unit weight (g/cm³) NBR NM 45 [³⁸[38] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR NM 45: Agregados - Determinação da massa unitária e do volume de vazios. Rio de Janeiro, mar. 2006.]	0.95	1.62	1.47
Clods of clay and friable materials (%) NBR 7218 [⁴¹[41] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 7218: Agregados - Determinação do teor de argila em torrões e materiais friáveis. Rio de Janeiro, agosto 1987.]	0	0	0
Rate of material passing through the sieve 75 µm (%) NBR NM 46 [⁴⁰[40] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR NM 46. Agregados - Determinação do material fino que passa através da peneira 75 µm, por lavagem. Rio de Janeiro, jul. 2003.]	-	0.69	2.37
Water absorption (%) NBR NM 53 [³⁵[35] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR NM 53: Agregado graúdo -Determinação da massa específica, massa específica aparente e absorção de água. Rio de Janeiro, jul. 2003.], NM 30 [³⁷[37] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR NM 30: Agregado miúdo - Determinação da absorção de água. Rio de Janeiro, jul. 2001.]	19	1.2	0.15

REF	0°C	200°C	400°C	600°C	800°C
f_c (MPa) Reduction %	40.62 100	32.12 79	24.06 59	11.17 28	7.83 19
E_c (GPa) Reduction %	31.75 100	26.45 83	8.35 26	2.69 8	1.50 5
S40	0°C	200°C	400°C	600°C	800°C
f_c (MPa) Reduction %	19.83 100	19.61 99	15.41 78	13.11 66	4.39 22
E_c (GPa) Reduction %	14.50 100	14.58 100	4.41 30	2.24 15	0.81 6
S100	0°C	200°C	400°C	600°C	800°C
f_c (MPa) Reduction %	16.44 100	13.38 81	12.59 77	6.97 42	3.31 20
E_c (GPa) Reduction %	12.67 100	11.48 91	4.25 34	1.66 13	0.62 5

	% of substitution of the coarse aggregate	Heating pattern	Type of heating	Cooling	Type of aggregate	Sample size
REF	0	RILEM/1ºC/min.	Slow	No load	Basalt	Ø = 100 mm H= 300 mm
S40	40	RILEM/1ºC/min.	Slow	No load	Basalt/ ceramic	Ø = 100 mm H= 300 mm
S100	100	RILEM/1ºC/min.	Slow	No load	Lightweight/ceramic	Ø = 100 mm H= 300 mm
ACI 216R	100	-	-	No load	Lightweight	Ø = 100 mm H= 300 mm
Souza and Moreno 2010	100	ISO 834.	Slow	No load	Lightweight (expanded clay)	Ø = 100 mm H = 200 mm
NBR/Eurocode	100	-	-	With load	Limestone	Ø = 100 mm H = 200 mm
Toric 2017	100	RILEM/2.5ºC/min.	Slow	No load	Lightweight (expanded clay)	Ø = 75 mm H = 225 mm
Martins 2016	100	RILEM/2.5ºC/min.	Slow	No load	Lightweight (ceramic)	Ø = 150 mm H= 300 mm

Author	Substitution rate (%)	Sample size (mm)	Type of aggregate	Heating pattern	Time of exposure (hours)	Type of analysis	Results
REF	0	150 x 150 x 100	Basalt	ISO 834	1	Visual	No spalling
S40	40	150 x 150 x 100	Basalt/ceramic	ISO 834	1	Visual	No spalling
S100	100	150 x 150 x 100	Lightweight/ceramic	ISO 834	1	Visual	No spalling
Ke Cheng He et al.	100	100 x 100 x 300	Expanded clay	10°C per minute	1	Visual and aggregate loss	Spalling when T > 400ºC
Laneyrie et al.	100	ϕ160 mm h = 50 mm	Construction and demolition waste	0.5°C per minute	2	Visual	No spalling
Martins et al	100	150 mm cubic	Ceramic waste	1.5 to 2.5°C/min	1	Visual	Minor spalling when T > 600ºC
Bodnóravá et al.	100	100 x 300 x 105	Expanded clay	ISO 834	-	Visual	Spalling when T > 700ºC

Brasil

Brasil

Lightweight concrete with coarse aggregate from ceramic waste at high temperatures

Abstract