Almofada de apoio de compósito de cimento para ligações em concreto pré-moldado

Abstract

This research presents a study of a mortar modified to use as bearing pad between precast concrete elements. The mortar used in this research is achieved by the introduction of styrene-butadiene latex (SB) and polypropylene fibers into a cement mortar and sand, modifying their mechanical properties, as increase of the potential deformation by decrease of the composite modulus of elasticity, providing favorable characteristics to the use as bearing pad for precast concrete elements. Cylindrical samples of 50mm of diameter with height of 100mm were used to determinate the compressive and the tensile strength and also the modulus of elasticity of the composite. Compression tests with cushions of 150mm x 150mm of base with thickness of 10mm were done to determinate the deformation capacity, rotation capacity and capacity of accommodation of imperfections and distribution of the stresses between precast elements. The results showed that the material has a capacity to deform in levels of tension from 10 to 20MPa maintaining his resilience. Values of rotations among 0.01 and 0.02rad were obtained, being these larger ones than the necessary values for most of the conventional cases of project. In the accommodation and distribution of the stresses, the presence of the bearing pad promoted an improvement of 25% in the strength of connections subject to uniform compressive stresses, with surface irregularities of 1.0mm.