Resistance to freezing and thawing of mortar specimens made from sulphoaluminate�?�belite cement

[摘要] Resistance to freezing and thawing of mortar specimens made from sulphoaluminateâ€�?�belite cement (Mâ€�?�SAB) is compared with that of mortars made from portland cement (Mâ€�?�PC). The results suggest that larger median radius of the pores and total porosity of Mâ€�?�SAB compared to those of Mâ€�?�PC are primarily caused by the rapid setting of the SAB cement. The `coarsening’ of pore structure of mortar specimens under action of freezing and thawing is proved by the increase in the macropores portion, median pore radius, and total porosity values. This process is more intense in Mâ€�?�SAB. The effect of the frost attack is confirmed by lower compressive strength and dynamic modulus of elasticity on the one hand and higher absorption capacity, expansion, and crack propagation of Mâ€�?�SAB compared with those of Mâ€�?�PC on the other hand. Besides the decreased frost resistance of Mâ€�?�SAB as compared with that of Mâ€�?�PC, unsatisfactory passivation of steel in Mâ€�?�SAB was found. The reason of this fact is the pH value decrease to less than 11.5 of the Mâ€�?�SAB extract.

[学科分类] 材料工程

[关键词] Frost resistance;low-energy sulphoaluminateâ€�?�belite cement;steel reinforcement corrosion.