Experimental Study on the Elastic Modulus of Cement Mortar with the Addition of Nano Metakaolin

This paper investigates the elastic modulus of cement mortar added with Nano metakaolin (NMK). In the experiments, we replaced 0%, 1%, 3%, 5%, and 7% of ordinary cement with NMK. The water to cement ratio of the prepared cement mortar is 0.5, while binder to aggregate ratio is 1:3. 150 cement mortar specimens with the dimension of 70.7 mm × 70.7 mm × 220 mm were fabricated in the laboratory. We measured the dynamic and static modulus of elasticity, compressive strength of the mortar specimens, at the specified curing ages (1, 3, 7, 14 and 28 days). Digital image correlation (DIC) technique were applied to continuously monitor the in-plane surface strain and displacement of the specimen. The surface stain obtained by DIC data were verified using strain gauge measurement. The effects of NMK contents, curing duration on the properties of NMK mortar were discussed. The experimental results demonstrated that the introduction of NMK improved elastic modulus, as compared to the cement mortar without NMK. The samples with 5% NMK exhibited the highest axial compressive strength and modulus of elasticity.