Carbonation action in reinforced concrete beams under stress regime carried out on full and small scales / Ação da carbonatação em vigas de concreto armado em serviço, construídas em escala natural e reduzida

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

This work reports on the behavior of carbonation in reinforced concrete beams under stress regime on full and small scales having the lowest possible frame. The beams were made with and without adding silica from rice husk and silica fume (Fe-Si). For each beam on a full scale (coarse aggregate with D máx. = 19 mm) another beam on a small scale was made with the same mix of concrete to maintain the same comparison parameter. The beams were cured for 7 days and subsequently submitted to flexure by applying a two-point loading (L/3 of beam). Humidity stabilization to stabilize internal humidity of beams exposed for 28 days in an environment with a concentration of 50% carbon dioxide, 65 + OR -5% of relative humidity and room temperature was carried out. The following was determined: axial compression strength, tensile splitting strength, youngs modulus and carbonation depth in cylindrical specimens. The carbonation depth was determined in specimens with unlike carbon dioxide concentration. Moreover, carbonation along beams on full and small scales and in cracks was observed. To estimate the carbonation depth of the beams, equations were adjusted to represent the carbonation in cracks. The results show the efficiency in the thickness of the cover, efficiency of small-scale models for studies concerning carbonation and behavior of carbonation in the serviceability of structural elements. The carbonation depth differs in the position of cracks, showing behavior which is unlike the one compared to specimens. The microstructure analyses show the behavior of carbonation depth in reinforced concrete beams complementing the experimental study. The results show that it is not sufficient to use high performance concretes in structural elements for elements with cracks and in aggressive atmospheres.

ASSUNTO(S)

crack concretes high performance concrete durability concretos carbonatação cover cobrimento concreto de alto desempenho carbonation durabilidade fissura

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