流体包裹体对混凝土高温性能的影响

An experimental study on influences of fluid inclusions on concrete properties at elevated temperatures

通过试验研究了混凝土细骨料中流体包裹体对混凝土高温性能的影响。发现流体包裹体发生热爆裂后，部分石英颗粒发生了碎裂，并对混凝土砂浆的高温性能有所影响。试验表明，天然砂和机制砂经过预热后制作的砂浆试块，其高温强度损失都低于同批次未经预热的本底砂制作的砂浆试块，并且预热温度越高，高温强度损失也相对较少；从高温试验现象观察到，部分砂浆试块在炉温升至400～500℃时发生了严重的爆裂，但天然砂和机制砂经过预加热后制作的砂浆试块均未发生爆裂。

This paper focuses on influences of fluid inclusions in quartz sand on concrete properties under high temperature. It was found by the experiments that some quartz grain particles would crumble with the decrepitation of fluid inclusions due to elevated temperatures and influence the high temperature prop erties of concrete mortar. The tests show that the high-temper ature strength losses of the samples made by pre-heated natural sand or manufactured sand are lower than that made by back- ground sand without preheating. Moreover, the higher the pre- heated temperature, the less the strength loss of cement mortar samples after high temperature. Observed from the elevated temperatures tests, explosive spalling occurred to some of the mortar samples when the furnace temperature up to 400～500℃, but not occurred to that by preheated natural sand and manufactured sand.