Mechanical Properties of Geopolymer Mortar after Exposure to Elevated Temperatures

This paper presents experimental results on mechanical properties of geopolymer mortar specimens, prepared by alkaline solution activating metakaolin and fly ash blend. Bending, compressive, tensile and bond strength tests were conducted on large sets of geopolymer mortar specimens at ambient temperature and after exposure to elevated temperatures, to evaluate the residual strength of geopolymer mortar at elevated temperatures. Comparative strength tests were also conducted on Portland cement mortar. Results from these tests show that bending, compressive, tensile and bond strength of geopolymer mortar increases at 100oC, and then decreases in 300- 700oC range. Geopolymer mortar exhibits a slightly lower bending strength, but higher compressive, tensile and bond strength, than ordinary Portland cement mortar at ambient temperature and after exposure to elevated temperatures. Thus MK-FA based geopolymer mortar can provide similar or higher level of fire resistance than Portland cement mortar in buildings, in addition to numerous environmental benefits, such as lower energy consumption and lower carbon dioxide emissions during production