An attempt to estimate the fulfillment of Kaiser Effect in earth concrete mixtures

Abstract

The ecological material in this study comprises earth concrete made with recycled sand (RS). Three mixtures contain 20%, 30% and 40% of clay in addition to RS and one mixture of 30% of clay and natural sand (NS) were prepared. The specimens were exposed for 28 days to a relative humidity of RH=90% and RH=50%. Uniaxial compression cyclic tests were carried out. This study presents the correlation of stress and AE activity in the pre-peak phase of each mixture. It is an attempt to assess the attainment of Kaiser Effect at different stress levels and different curing conditions. The results show that at RH=90%, all mixtures attained or at least were not far from attaining Kaiser Effect. However, at RH=50%, as a result of shrinkage induced cracking, Kaiser effect was not fulfilled. Interestingly, the mixture with higher clay content showed remarkable increase in AEs at dried conditions compared to its state at RH=90%.