纤维增强珊瑚混凝土的力学性能研究及破坏形态分析

Study on mechanical property and damage morphology analysis of coral aggregate concrete with fiber

采用天然珊瑚碎屑作为粗骨料,研究在水灰比为0.4的条件下不同掺量的碳纤维、聚丙烯纤维和剑麻纤维珊瑚混凝土的基本力学指标。试验表明,随着纤维掺量的增加,珊瑚混凝土的立方体抗压强度、劈裂抗拉强度、抗折强度、弹性模量均呈现先增加后减小的趋势,总体来看,最优碳纤维掺量为2 kg/m3,最优聚丙烯纤维掺量也是2 kg/m3,最优剑麻纤维掺量为4.5kg/m3。当掺入纤维过量时,珊瑚混凝土分散性降低,从而增加浆体薄弱界面,无法发挥其增强、增韧的效应反而使其强度有所下降。纤维材料能明显改善珊瑚混凝土的脆性,增加韧性,使其抗折性能显著提高,改变珊瑚混凝土的破坏形态,试件破坏时依然能保持良好的整体性。

Using natural coral debris as coarse aggregate,under the condition of water cement ratio of 0.4,it was studied the basic mechanical indexes of different content of carbon fiber,polypropylene fiber and sisal fiber coral aggregate concrete.Results showed that the cube compressive strength,splitting tensile strength,bending strength,and elastic modulus of coral concrete firstly increased and then decreased with fiber content increase.Overall,the optimal content of carbon fiber was 2 kg / m3,and that of polypropylene fiber was 2 kg /m3,and that of sisal fiber was 4.5 kg / m3.When mixed with fiber excess,the dispersibility in coral aggregate concrete is reduced,and slurry weak interface increased.So it cannot play its enhancement and toughening effect that the intensity decreased.In addition,mixing fiber into coral aggregate concrete can obviously improve the brittleness,toughness and bending performance significantly,and change the damage form of coral aggregate concrete,therefore,whem the specimen destroyed,it can still maintain good integrity.