Effect of peach shell as lightweight aggregate on mechanics and creep properties of concrete

Peach shell (PS) used as a substitute for normal weight aggregate (NWA) in concrete was investigated. A series of mixes were prepared by 0%, 25%, 50%, 75% and 100% PS as a substitute for NWA, while other parameters were set as constant. Results showed that 100% alternative NWA with PS, compressive strength, splitting tensile strength, flexural strength, modulus of elasticity reduced by 44.0%, 34.5%, 46.5% and 43.4%, respectively, and 24-h water absorption and porosity were 10.2% and 17.4%, respectively. However, its oven-dry density was 25% lighter than the control mix. Creep results showed that the creep strain of concrete and the concentrations of K+, Ca2+, Na+, Mg2+ and Sr2+ in the concrete solution increased significantly with the increase of PS content, and the creep strain of P0, P25, P50, P75 and P100 mixes at 570 h were 1.82 x 10(-4), 6.96 x 10(-4), 9.09 x 10(-4), 11.21 x 10(-4) and 15.12 x 10(-4), respectively. After creep test, the compressive strength of all mixes increased. The results show that PS can be utilised to produce lightweight aggregate concrete, and the maximum replacement of NWA with PS beyond 50% is not recommended.