Effect of metakaolin addition on the mechanical performance of granulated blast furnace slag based geopolymer mortar with micro-encapsulated phase change materials

Abstract

The incorporation of microcapsule phase change materials (MPCM) in geopolymer is one of the effective technologies that contribute to improve the thermal comfort of buildings on the one hand and replace the use of Portland cement-based materials on the other hand. Although MPCM increases the thermal capacity of the cementitious matrix, whether it is based on cement or geopolymer, their incorporation has unfortunately several negative effects on the mechanical performances. This scientific problem is still unsolved and several researchers have pointed it out. This study aim to investigate the effect of 10 and 20% metakaolin(MK) inclusion on the mechanical performance of geopolymer-MPCM mortars based on granulated blast furnace slag (GBFS) and to compares them with Portland cement-MPCM based mortars. Different tests were performed for to types of mortar in the aim to characterize their properties such as workability, porosity, compressive strength, dynamic Young's modulus and dynamic shear modulus. The results show that the inclusion of two proportions of metakaolin compensated well for the loss of mechanical strength related to the incorporation of MPCM. Therefore, with up to 20% of MPCM the inclusion of metkaolin increased the compressive strength by about 10 MPA. In addition, all geopolymer-MPCM mortars showed high compressive strength, improved workability and reduced porosity compared to Portland cement-MPCM based mortars.