Air-entraining agent,as a common admixture of concrete,is widely used because of its excellent properties.However,at present,it' s not yet clear how the air-entraining agent influences the fire resistance properties of concrete.The article takes C30 concrete as an example and studies the influence of air-entraining agent on the thermal conductivity and compressive strength at 600 ℃ by experiments.The results shows that,compared with ordinary concrete,under the same heating conditions,air-entraining agent can reduce the thermal conductivity and the temperature inside the specimens by improving the internal micro pore structure.At the same time,although the bearing capacity of the test pieces is lower slightly,its stability is better because of the weaker development of fracture inside the test pieces.%引气剂作为混凝土常用外掺剂,凭借优异的性能逐渐得到广泛应用,但其对混凝土耐火性的影响尚不明确.以C30混凝土为例,通过试验探究了600C℃情况下引气剂对混凝土导热性及抗压强度的影响.试验结果表明,与普通混凝土相比,在相同的加热条件下,引气剂通过改善混凝土内部微孔结构,能够降低材料导热系数,一定程度上降低试件内部温度.同时,掺入引气剂的试件内部裂隙发育程度较弱,残余承载力虽稍逊于普通混凝土,但材料稳定性更好,试件残余承载力离散性更小.
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