Chemical shrinkage of cementitious pastes with metakaulin incorporation

Abstract This study shows the influence of partial replacement of Portland cement by metakaolin in the hydration reactions and chemical shrinkage of cementitious pastes. For this, pastes were prepared using metakaolin replacements of 5, 10 and 20% by mass, and a reference paste, using a constant water/solid ratio of 0,5. Chemical shrinkage was measured continuously automating the method of dilatometry, hydration kinetics was evaluated using an isothermal conduction calorimetry. Additionally, the development of the microstructure was studied by thermogravimetric analysis and X-ray diffraction. The results show that there is an excellent relationship between chemical shrinkage and calorimetry and the addition of metakaolin leads to changes of the hydration kinetics, which also affect the chemical shrinkage.