Durability of polymer-modified lightweight flowable concrete made using expanded polystyrene

Abstract

Lightweight self-consolidating concrete (LWSCC) intended for structural and repair applications combines the advantages of improved workability and reduced dead loads resulting from the structure self-weight. This investigation evaluates the coupled effects of expanded polystyrene (EPS) and styrene-butadiene rubber (SBR) latexes on durability-related properties of LWSCC weighing between 1870 to 2360 kg/m3. The water-to-binder ratio (w/b) was regulated to ensure similar compressive strengths. Test results showed that the transport properties including sorptivity, corrosion, and chloride ion penetration were pretty similar to the control normal-weight concrete, despite the decrease in density. This was attributed to a combination of phenomena such as lower w/b that refines the concrete microstructure, EPS particles that function as internal barriers, and presence of SBR polymers that create dispersed network of impermeable films. The incorporation of SBR was beneficial to improve bonding strengths of composite slabs, especially when exposed to repeated freeze/thaw cycles. Compared to normal-weight concrete, the resistance to chemical attack improved when LWSCC is prepared with reduced w/b and/or SBR additions. Different regression models are proposed to predict the concrete durability as a function of w/b, EPS, and SBR rates.