Properties of alkali-activated slag and fly ash blended sea sand concrete exposed to elevated temperature

AbstractAlkali-activated slag and fly ash (FA)-blended seawater sea sand concrete (AASC) is a new type of concrete produced without Portland cement or river sand. The advantages of utilising industrial waste and marine resources are that they are not only eco-friendly but cost-saving. This study aimed to investigate the properties of AASC exposed to elevated temperatures. Slag and FA were activated using NaOH and water glass solutions for mixing AASC. Heating and compressive tests were conducted to analyse the thermal and compressive properties of the AASC. The results showed that the AASC with higher FA content (Type II) had fewer flaky structures and more integral interfacial transition zones than the other type of AASC (Type I) after exposure to 600 °C. Type I AASC had better mechanical performance at temperatures below 400 °C but was inferior to Type II AASC beyond 600 °C. A compressive constitutive model was proposed for AASC.Keywords: alkali-activated materialsseawater sea sand concretethermal propertiescompressive propertieselevated temperature Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThe authors gratefully acknowledge the support received from the National Natural Science Foundation of China (Grant No. 52178259), the Major Program of the Natural Science Foundation of Shandong Province (Grant No. ZR2020KA001), Special Project of Science and Technology Benefiting the People of Qingdao (Grant No. 21-1-4-sf-18-nsh), and Technical Service Project by Qingjian Group Co., Ltd. (Grant No. 20220149).