Microstructural Properties of Polymer-Modified Bitumen Emulsion-Cement Composites Considering the Production Method

Abstract

The present study investigated the effect of the polymer-modified bitumen emulsion production method on the properties of cement-polymer emulsion paste. Modified emulsions were made using three methods, including comilling, soap prebatching, and postblending. During comilling, water, acid, styrene-butadiene rubber polymer, emulsifier, and bitumen were added simultaneously to the colloidal mill. In soap prebatching first water, acid and emulsifier were mixed to produce the soap. Then, polymer was added to the soap, and the resulting compound is added simultaneously to a colloidal mill with the bitumen. During postblending, water, acid, and emulsifier were first mixed. Then, this mixture and bitumen were added to the colloidal mill. Next, polymer was added to obtain the polymer-modified bitumen. Portland cement was added to the produced polymer-modified emulsions and cured at 40°C for 72 h. Field emission scanning electron microscopy and energy dispersive X-ray spectroscopy tests were performed on the samples to investigate the weight distribution, dispersion of elements, and hydration rate of cement particles. Using the X-ray diffraction test, cement hydration products were identified, and the particle dispersion of these products was investigated. Moreover, the microstructure, adhesion, and elastic modulus of the samples were examined using atomic force microscopy. Based on the results and analyses, the highest homogeneity in particles distribution due to hydration of cement and the highest elastic modulus in cement samples were related to those made by postblending, whereas the soap prebatching methods resulted in the highest adhesion in cemented samples.