Utilization of steel slag, iron tailings and fly ash as aggregates to prepare a polymer-modified waterproof mortar with a core–shell styrene–acrylic copolymer as the modifier

Using Poly(styrene-co-hydroxyethyl methacrylate) (P(St-co-HEMA)) microsphere with a core–shell structure as the modifier, a new polymer-modified waterproof mortar was developed with steel slag, iron tailings and fly ash as aggregates. Effects of cement–aggregate ratio, polymer–cement ratio and defoamer–cement ratio on performances of this mortar were investigated. The factor design was used to determine the optimal conditions: polymer–cement ratio, 12 wt.%; cement–aggregate ratio, 1:2.5; defoamer–cement ratio, 0.8 wt.%. The product conformed to Chinese norms. Furthermore, the mortar with P(St-co-HEMA) as the modifier gave better mechanical properties and water resistance compared to those with commercial ethylene–vinyl acetate copolymer (EVA) and styrene–acrylic copolymer (SAE) as modifiers. Microstructures of these polymer-modified mortars were compared and discussed.