Multi-scale analysis of styrene butadiene latex modified PVA fiber concrete

Abstract

Polyvinyl alcohol (PVA) concrete is a new green building material. In order to make it more widely used, this study used butylbenzene emulsion (SBL) to modify PVA fiber concrete. The enhancement mechanism of SBL on the PVA/cement interface was systematically investigated at multiple scales, including macroscopic mechanical properties, microstructural characteristics, nano-interface interactions. On a macro scale, the addition of SBL and PVA fibers can significantly improve the shear strength and flexural strength of composite concrete at 7 and 28 days, and SBL can make up for the decrease in compressive strength caused by PVA. On a micro scale, the corresponding polymer cement concrete was tested by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). It was observed that some gels and polymers filled the interfacial gap and effectively repaired the interfacial defects. The SBL brought the two interfaces closer together and described its bonding effect at the micro-interface. On the nano scale, SBL/PVA/C-S-H is modeled by molecular dynamics method. Binding energy, Relative concentrations, Radial distribution function, Mean-square displacement and Time correlation function were analyzed and calculated. The results show that SBL reduces the interfacial effect, enhances the interfacial hydrogen bond, van der Waals interaction, Ca-H coordination bond and stability, improves the interfacial adhesion, and further enhances the weak interfacial bond between organic polymer (PVA) and inorganic silicate (C-S-H).