THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF CEMENTITIOUS MATERIALS COMPRISED OF LIMESTONE, CALCINED CLAY AND CLINKER

Limestone, calcined clay and cement (LC 3 ) are one of the low carbon cement materials which are used as a partial substitution of clinker and Portland cement. In this study, the effects of limestone and calcined clay (LC 2 ) on the mechanical properties and microstructure of mortars were studied under multi-scales. It could be concluded that the compressive strength decreased slightly with an increase in the LC 2 content, but the flexural strength increased significantly due to the greater formation of crystalline aluminates in the LC 3 . The x-ray diffraction and thermal analysis results prove the pozzolanic activity of the calcined clay in the LC 3 system which is in agreement with the results of the decreasing calcium hydroxide and the increasing ettringite content, and the LC 2 could reduce the heat of the hydration of the LC 3 significantly. Also, the formation of calcium hemicarboaluminate (3CaO