Performance and ITZ of pervious concrete modified by vinyl acetate and ethylene copolymer dispersible powder

Abstract

This work aimed to assess the influence of vinyl acetate and ethylene copolymer dispersible powder (VAE-P) on the performance and interfacial transition zone (ITZ) of pervious concrete, and explore the mechanism responsible for the resulted performance. Various pervious concretes and mortars were prepared, and the porosities, water permeability coefficients and strengths of pervious concretes were assessed, the fluidities, shear viscosities, air contents and strengths of various mortars were measured. The crystalline phase, pore characteristic and VAE-P layer in the ITZ were also investigated. The results indicate that VAE-P enhances fluidity and air content, and declines shear viscosity of fresh mortar. These pervious concretes with lower or similar porosity than the control still provide similar or better water permeability. It reduces mortar strength, but it significantly improves pervious concrete strengths. ITZ results indicate that it delays cement hydration, alters pore characteristic and especially increases the volume of pores with larger size. It increases VAE-P layer thickness. The pervious concrete with 10% VAE-P displays a cross-linked network layer structure. The pervious concrete with 5% VAE-P provides the lower strengths than that with 2.5% VAE-P, but pervious concretes with more VAE-P have relatively higher strengths. These results provide a reference for the preparation of pervious concrete with VAE-P.