Chloride binding and desorption properties of the concrete containing corn stover ash

Abstract

This study investigates the performance of binary blended concrete mixtures containing ordinary Portland cement (OPC) and corn stover ash (CSA) in terms of chloride ingress, chloride binding capacity, and resistance to chloride desorption. Concrete mixtures with water-to-cementitious material ratios of 0.45 and 0.54, and CSA replacement levels of 5 and 20% by mass of cement were prepared and exposed to various chloride solution concentrations ranging from 0.1 to 2 mol/L after 28 and 112 d of curing. Results show that pretreated CSA can improve the long-term chloride resistance of concrete, mainly due to its positive influence on promoting pozzolanic reactions. The results demonstrate that CSA concrete has a lower chloride binding capacity than OPC. However, the chloride desorption testing results in a low-pH environment suggest that CSA concrete is more durable than OPC concrete, and fewer chlorides disassociate from a drop in pH of the exposure solution.