Effect of rice husk ash surface modification by silane coupling agents on damping capacity of cement-based pastes

Abstract

Damping capacity of cement-based composites can be of practical importance for civil infrastructure applications. This work started with optimizing the calcination process of rice husk ash (RHA), followed by chemical treatment to achieve a porous structure on RHA surface. Silane coupling agents (SCAs) were subsequently used to alter the interface and connections between the RHA and cement-based matrix. In the 1st stage, the RHA calcined at 600° C for 1.5 h and then treated with HCl solution showed the highest index of pozzolanic activity (IPA). The HCl treatment also significantly increased the pore volume, surface area, and average pore size of RHA-I to 0.18 cm3/g, 17.86 m2/g and 43 nm, respectively. In the 2nd stage, the SCAs altered the surface of RHA by physical adhesion and bonding effect, and the pore volume, surface area and average pore size of RHA-II became 0.15–0.21 cm3/g, 18.0–50.0 m2/g and 11–32 nm, respectively. Based on the surface and pore structure modifications, the RHA-II was used to improve the damping performance of cement-based pastes and dynamic mechanical thermal analysis (DMTA) was performed to test the damping capacity of the pastes. Silane A151 fulfilled the function of improving the damping performance of cement-RHA pastes. Specifically, RHA-II-A151 increased the loss tangent value up to nearly 0.06 around −30° C.