Durability of sustainable sulfur concrete with fly ash and recycled aggregate against chemical and weathering environments

• A partial replacement of modified sulfur by fly ash increased the strength of sulfur concrete.
• The elastic modulus of sulfur concrete was about 20% smaller than that of normal Portland cement concrete.
• Sulfur concrete with recycled aggregate presented much higher chemical resistance than that with natural aggregate.
• Using fly ash as a substitution of modified sulfur caused a roughly 20% reduction in the CTE of sulfur concrete.
• Sulfur concrete with recycled aggregate showed a lower RDME than that with natural aggregate.

Fossil fuel consumption is rapidly increasing all over the world, and so is the amount of sulfur yielded as a byproduct of petroleum refining processes. A huge cost of waste disposal will be demanded if no counterplan is prepared for constantly growing sulfur production. As an innovative solution, using sulfur for the role of a binder in concrete has been recently pursued to replace entire cement and water.This study investigates the mechanical and durability properties of sulfur concrete made with fly ash and recycled aggregate; effects of the sustainable materials are explored as an effort to maximize the sustainability of sulfur concrete. Based on the results of preliminary tests, three types of mix proportions are designed for further investigation. The key test variables are the partial replacement of modified sulfur by fly ash and the type of coarse aggregate (natural or recycled). In all concrete mixtures, neither cement nor water is included. The durability properties of sulfur concrete in severe chemical and weathering environments are explored, including chemical resistance, freezing–thawing resistance, and coefficient of thermal expansion. Essential mechanical properties such as compressive and tensile strengths and elastic modulus are also examined.