Effect of New Composite Early Strength Agent on Mechanical Performance of Cement Mortar

Abstract

Abstract: In this paper, the effects of two new composite early strength agents (calcium formate-crystal embryo and methacrylic acid-crystal embryo) on the fresh properties and mechanical performances of cement mortar were studied, and the samples were micro-analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that with the increase of the early strength agent content, the fluidity of the fresh cement mortar decreases slightly, and the setting time advances. Both two composite early strength agents accelerate the early hydration of the cement and significantly improve the early strength of the cement mortar. Calcium formate-crystal embryo and methacrylic acid-crystal embryo composite early strength agents increase the 12 h compressive strength of cement mortar by 96.7% and 89.3%, and the flexural strength by 192.2% and 211.1%, respectively. At the same time, the 28 d compressive strength of cement mortar still increases by about 50.0%, indicating that the two types of early strength agents have no negative impact on the later strength development of cement mortar. XRD and SEM analysis both confirm that adding two kinds of composite early strength agents improve the hydration degree of cement, increase the hydration products, and improve the structure compactness.

Key words: composite early strength agent, cement mortar, fluidity, mechanical strength, microstructure

CLC Number:

TU528.0

LIU Chunying, REN Guosheng, GAO Xiaojian. Effect of New Composite Early Strength Agent on Mechanical Performance of Cement Mortar[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2020, 39(12): 3806-3811.

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