Hydration and carbonation reaction competition and the effect on the strength of under shed air dried Amended Compressed Earth Blocks (ACEBs)

Abstract

A research finding on amended soils for the production of blocks  and mortar with lime and natural pozzolan for earthen construction was reported in the EEA Journal of 2019. The use of the amenders was to take advantage of the binding property of lime and the low reactive behavior of natural pozzolans without any further energy demanding additional treatment. In the attempt, it was learned that the existence of hydration and carbonation reactions which are the driving engines of the whole formation are competing with each other at early age of curing. The effect of this phenomenon is that it might upset the maximum/optimum stabilizing effect that could be fully achieved. Furthermore, since the proposed method was defined for air dried curing but only under shed environment; it came to mind that such a challenge needs to be addressed before embarking on an industrial scale. Thus, the main objective of this research is to investigate the effect of hydration and carbonation reaction competitions on air dried blocks in lieu of those cured under the influence of moisture to make a decision on their ultimate use. In order to understand the existence of the reactions’ competition various curing mediums were experimented upon and a comparison is made to figure out the weakness of the air dried blocks and those matured at six more environments. From the finding, it is concluded that, among the contending curing conditions as for the purpose of this research, both under shed air drying and a plastic cover moist curing for 14 days and a subsequent 14 days air dry curing under the ambient lab environment (totaling 28 days) could equally be used as  convenient. It is also confirmed that, the proposed curing of ACEBs under shed within an air dry condition is a well suited proposition for the practice; since the competition doesn’t seem to affect its anticipated performance; per the finding.