Evaluation on Frost Resistance of Early Age Magnesium Potassium Phosphate Cement Mortar

Abstract

Abstract: In order to study the frost resistance of early age magnesium potassium phosphate cement (MKPC) mortar, the strength, volume deformation and water absorption of early age MKPC mortar specimens which were rapidly frozen and thawed in water and 5% (mass fraction) Na₂SO₄ solution were tested, and the phase composition and micro morphology were analyzed. The results were compared with those of MKPC mortar specimens after 28 d hydration. The results show that the strength attenuation degree of early age MKPC mortar specimens (hydration age more than 1 d) is lower than that of hydration 28 d under rapid freeze-thaw cycle environment. After freeze-thaw cycle 225 times, the residual strength of MKPC mortar specimens at early age is close to that of 28 d hydration age specimens, and the strength attenuation degree of MKPC mortar specimens under sulfate freeze-thaw cycle environment is lower than that of MKPC mortar specimens under water freeze-thaw cycle. The early age MKPC mortar specimens (hydration age more than 1 d) have better deformation resistance under freeze-thaw cycle environment, and it is obviously better than that of MKPC with hydration age of 28 d. The deformation resistance of MKPC mortar specimens under water freeze-thaw cycle is better than that of MKPC mortar specimens under sulfate freeze-thaw cycle. The effect of freeze-thaw cycle on the pore structure of MKPC mortar hardened body after 28 d hydration is stronger than that of 1 d hydration. The open porosity of MKPC mortar hardened body subjected to sulfate freeze-thaw cycle is lower than that of water freeze-thaw cycle.

Key words: magnesium potassium phosphate cement, hydration age, frost resistance, strength, volume deformation, water absorption

CLC Number:

TU528.3

MIAO Hanliang, ZHAO Bin, JI Rongjian, YANG Jianming. Evaluation on Frost Resistance of Early Age Magnesium Potassium Phosphate Cement Mortar[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2021, 40(4): 1128-1136.

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