Effect of Clay Brick Powder on ASR Expansion Control of Rhyolite Mortar Bar

Abstract

This paper investigated the effect of clay brick powder (BP) on expansion behaviors of mortar bars using rhyolite aggregates, local volcanic rock from central Thailand. The accelerated test condition (ASTM C 1260) was used in this study. The expansion of samples with varying percentages of BP as cement replacement were compared to those of cement mortar bars. The brick powder significantly reduced expansion of mortar bars. As the percent replacement increased, the larger percentage of expansion reduction was. Due to the possible negative effects on mechanical properties of the mixture, the amount of the supplementary materials should be kept as low as possible. The mixture with 30% BP which yielded expansion below 0.05% at 14 days after acceleration, was chosen to study the effect on strength reduction, compared to the plain mixtures under normal and accelerated conditions. Compressive strength of BP samples under accelerated condition was slightly lower (approx.4%) than that of under normal curing while the strength of control mix was significant lower (of 18%) under similar conditions.