掺和料及引气剂对水泥混凝土热膨胀系数的影响

Influence of Mineral Admixtures and Air-Entraining Agent on Thermal Expansion Property of Cement-Based Materials

研究了粉煤灰、矿粉和引气剂对水泥基材料热膨胀系数的影响.结果表明:在相同掺量下,矿粉水泥砂浆的热膨胀系数明显大于粉煤灰水泥砂浆的热膨胀系数;水泥砂浆和混凝土的热膨胀系数均随着粉煤灰掺量的增加而降低,在粉煤灰掺量小于20%(质量分数)时,单位抗压强度热膨胀系数随着粉煤灰掺量增加而降低,当粉煤灰掺量大于20%时,粉煤灰在降低热膨胀系数的同时会引起抗压强度较大衰减;随着混凝土含气量的增加,其单位抗压强度热膨胀系数增加.

Mineral admixtures and air-entraining agent are the important component of high-performance concrete. The influence of fly ash, slag powder and air-entraining agent on the thermal expansion property of cement-based materials was studied. The results fall into several aspects. Firstly, with the same mix amount, the coefficient of thermal expansion（CTE） of mortar containing slag powder is much higher than that of mortar containing fly ash. Secondly, with the increase of fly ash content, the CTE of both mortar and concrete decreases accordingly. When the fly ash content is less than 20 %, the CTE per unit compressive strength decreases with increasing fly ash content. When the fly ash content is over 20%, the compressive strength of concrete will decrease too much. Lastly, the CTE of concrete decreases with the increase of air content, but the strength of concrete is reduced.