Influence of curing methods on the mechanical performance of bamboo stem ash cement blended bricks

The influence of different curing methods on the strength and durability of bamboo stem ash (BSA) cement blended bricks was investigated. BSA was introduced into the mixture by direct substitution with cement in proportions of 0%, 5% and 10%.  The materials were batched by volume using a binder/sand mix ratio of 1:6. Four curing conditions were examined; water immersion, intermittent water sprinkling, wet rug covering and open-air exposure. The hardened brick specimens were tested for their compressive strength and abrasive resistance. Specimens cured by water immersion were found to possess the highest compressive strength and abrasive resistance. An increase in BSA content was associated with a corresponding decrease in compressive strength and abrasive resistance, however, the 28-day strength activity index (SAI) of all modified specimens satisfied the physical requirements of ASTM C618 (SAI ≥ 75%) across all curing conditions. The compressive strength of all specimens at 28 days satisfied the requirements of the Nigerian Industrial Standard (NIS 978) for non-load bearing bricks (1.5 – 3.5 N/mm2). The differences in 28-day strength for specimens cured by water immersion and those cured by wet covering, sprinkling and open-air, were 3.45%, 21.38% and 29.31%, respectively, for the control specimens (0% BSA content); while for the modified brick specimens, these differences were 5.6%, 19.2% and 31.6%, respectively, for 5% BSA content; and 9.48%, 23.28% and 32.33%, respectively, for 10% BSA content. Curing by complete submersion in water was observed to be the most reliable in promoting adequate strength gain and wear resistance in the brick specimens.