Carboxy styrene-butadiene latex and PVA fiber co-modified rubber concrete-experiment and molecular dynamics simulation

Rubber concrete (RC) is a new environmentally friendly composite material, there are many weak interfaces and pores inside it, which degrade its mechanical properties. To address this problem, this study coordinates the modification of RC with carboxy styrene butadiene latex (CSBL) and polyvinyl alcohol (PVA) fibers to improve its mechanical properties. From mechanical properties experiments, it was found that 0.6% cement mass of PVA fiber and 10% cement mass of CSBL could increase the compressive and shear strengths by 12.4% and 30%, respectively. A series of microscopic tests (Scanning Electron Microscope-SEM, X-ray diffraction-XRD, Fourier Transform Infrared Spectrometer-FTIR) revealed that PVA fibers limited the development of cracks and CSBL caused further hydration of unhydrated cement to produce more cement gel, which in turn filled the internal pore structure of concrete. Molecular dynamics simulation techniques were used to create hydrated calcium silicate (C-S-H)/CSBL, rubber/CSBL and PVA/CSBL models. Dynamic and static simulations of the interfaces based on the above models revealed that CSBL is used to enhance the bonding between materials through a large number of stable hydrogen and ionic bonds. In this study, the enhanced RC is analyzed at multiple scales, which provides experimental and theoretical support for its application in engineering.