Strength and microstructural characteristics of sulfur polymer composites containing binary cement and waste rubber

This study investigated the strength and microstructural characteristics of modified sulfur polymer composites employing several industrial wastes (such as sulfur and rubber) and binary cement (blend of fly ash and Portland cement) as primary components. Modified sulfur played a role of a binder in the sulfur composites. Portland cement was blended together with fly ash in the binary cement that was used as a micro-filler, as well as a potential crack-healing agent, in the sulfur composites. Rubber powder from waste scrap tires was used as a substitute of fine aggregate. A total of 24 different mixtures were tested by varying the mix proportions of sulfur, binary cement, and rubber powder. The test results revealed that the highest compressive strength of the sulfur composites for a given rubber powder ratio was acquired from the use of 40% binary cement ratio. A broad series of microstructural analyses, including SEM, XRD, and FT-IR spectroscopy, confirmed the beneficial effect of the binary cement (up to 40%) on the strength of the sulfur composites, and supported its potential role in crack healing.