Estudo de agregados lateríticos para utilização em concretos estruturais.

Abstract

This work deals with the behavior of lateritic concrete where the traditional gravels were replaced by lateritic concretions and micro-silica and plastificant were also added in production of the hard-wearing structural concrete. The lateritic concretions were colleted in borrow pits in the region of Jacumã in Paraíba state. Initially it is presented a review of the literature and several topics related to high performance concrete and its significance, lateritic concretions and lateritic concrete. This is follow by a comparative study between conventional concrete beams using gravel from granite rock and concrete made with lateritic concretions in as large gravels and shown the phenomenon more clear in deterioration of the structural concretes. For this investigation, used two methodologies for the lateritic aggregates, initially wash and processed; no washed. After the characterization tests were done, were prepared concrete mixes in the proportions of 1:6,5, 1:5,0 and 1:3,5. The specimens were put in water, and one of the mixtures the curing were done in heat chamber. The specimens were prepared and submitted to unconfined compressive strength determinations with 3, 7, 14 and 28 days for curing time. The determination of the modulus of elasticity of the lateritic concrete, ultra sonic tests were used as well as loading cycles and showed significant differences for all specimens tested. Were made analysis about possibility of the lateritic concrete were used in environmental submitted the aggressive according to Brazilian standard for concrete, NBR 6118: 2003. It was observed that the methodology used in this investigation for the determination of the grain size distribution for lateritic concretions showed um remarkable gain in unconfined compressive strength. Also, the micro-silica added in the selected levels did not increase the unconfined compressive strength, as it was anticipated.