Hardened paste of alkali-activated phosphorous slag cement and structure of paste-aggregate interface

In order to study the high-strength mechanism of alkali-activated phosphorous slag cement,the structures of the alkali-activated phosphorous cement paste and the paste-aggregate interface were studied using scanning electron microscopy,and the pore structure of the hardened paste was investigated using a mercury intrusion porosimeter.These features were compared with those of Portland cement paste.The results show that the structure of the alkali-activated phosphorous cement paste is dense with low porosity and a small pore size,compared with that of the Portland cement paste.The paste is tightly connected with aggregate,and there was no orderly development of Ca(OH)2 crystals and a relatively looser structure at the paste-aggregate interface,which usually exists in Portland cement paste.