On-line version ISSN 1678-8621
VIEIRA, Geilma Lima and MOLIN, Denise Carpena Coitinho Dal. Evaluation of compressive strength, tensile strength and microcracking formation in concretes produced with different cements, when a preloading of compression is applied. Ambient. constr. (Online) [online]. 2011, vol.11, n.1, pp. 25-40. ISSN 1678-8621. http://dx.doi.org/10.1590/S1678-86212011000100003.
Many construction companies seeking competitive advantage in the market search for solutions to increase the speed of their projects, such as reducing the structure execution time, cutting shoring time and expediting the construction of masonry walls, disregarding the minimal time limit for curing concrete. Early withdrawal of the concrete structure shoring submits it to a premature load. The damage caused by incomplete hydration reaction and curing of the concrete can trigger a widespread process of formation of microcracks. This study examined the behavior of different types of concrete produced with four different types of cements, subjected to an early compressive load, analyzing their mechanical properties. The analysis included an evaluation of the compressive strength, tensile strength and internal microstructure of the concrete, using scanning electron microscopy. The results indicated that there is a possibility of forming microcracks due to preloading on concrete, and that there is a tendency of reaching lower tensile strength values. However, microscopic analysis showed that the microcracks formed by preloading tend to recover if either the curing process is resumed or if early loading stops.
Keywords : Concrete; Preload; Compressive strength; Tensile strength; Microcracking.