Influence of ultra-fine steatite powder on the properties of alkali-activated concrete

Alkali-activated binders are emerging sustainable binders in the construction sector due to their higher strength and superior resistance against aggressive environments than those of cement concrete. Steatite powder is obtained as a by-product of soapstone processing and disposed of as waste in large quantities. Studies on the reuse of steatite powder in alkali-activated concrete are few. Hence, the current research focuses on the influence of ultra-fine steatite powder on the mechanical as well as durability properties of slag- and fly-ash-based alkali-activated concrete. Six replacement levels (10, 20, 30, 40, 50 and 60%) of slag and fly ash with steatite powder were adopted and activated using a sodium-based activator. Heat curing and ambient curing were performed for fly ash–steatite concrete and slag–steatite concrete, respectively. From the test results, 30% steatite powder is the optimum for slag- and fly-ash-based alkali-activated concretes. Less water absorption and higher resistance against acid exposure are observed for steatite-based alkali-activated concrete specimens.