Effect of the combination of polyvinyl chloride (PVC) and steel slag waste on the durability and mechanical properties of composite mortars

The ever-increasing demand for concrete production makes it vital to consider concrete stainability and reduce the
environmental impact of its production for sustainable growth. One of the most effective methods to achieve concrete
sustainability is incorporating waste materials into concrete mixtures. The main objective of this study is to investigate the
properties of sustainable cement pastes and mortars containing steel slag and polyvinyl chloride (PVC) waste powder. The
experimental study used different proportions (0%, 5%, 10%, 15%, and 20%) of steel slag and PVC waste powder as partial
replacement for Portland cement. The durability and mechanical properties of mortar composites are evaluated using various
testing methods, including ultrasonic pulse velocity (UPV), compressive strength, electrical resistivity, sulfate attack, acid
attack, and porosity testing. Fourier transforms infrared spectroscopy, X-ray diffraction, and scanning electron microscopy
(SEM) are used to find the hydration products of different cement paste samples. The study revealed that replacing 10%
slag into the mortar mixtures caused a significant increase in compressive strength. The measured electrical resistivity and
UPV results are deemed satisfactory. The X-ray diffraction analysis confirmed the existence of significant portlandite peaks
in the sample, which had 10% slag. The SEM analysis of the mortar samples revealed a compact and dense microstructure
in the sample containing 10% slag. Therefore, a replacement level of 10% of the steel slag and PVC powder is optimal for
developing high-performance mortar. These findings contribute to the current state of knowledge and help researchers better
understate the performance of the studied waste materials and their contributions to concrete sustainability.