Mechanical properties and frost resistance of recycled brick aggregate concrete modified by nano-SiO₂

Abstract In this work, brick aggregates were immersed in nano-SiO 2 solution for days, and the effects of on aggregate properties, mechanical properties (compressive strength, flexural splitting tensile strength), frost resistance (apparent phenomenon, mass loss, relative dynamic modulus elasticity, compressive strength) recycled concrete microstructure investigated. The results show that can effectively improve performance concrete, mainly by reducing water absorption crushing index improving strength. With increasing concentration, strength first increase then decrease. is superior to ordinary while -modified inferior concrete. addition, freeze‒thaw damage mechanism analyzed, a life prediction model based Weibull distribution proposed.