Effect of Fly Ash and PVA Fiber on Microstructural Damage and Residual Properties of Engineered Cementitious Composites Exposed to High Temperatures
Effect of Fly Ash and PVA Fiber on Microstructural Damage and Residual Properties of Engineered Cementitious Composites Exposed to High Temperatures
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DOI：
10.1061/(asce)mt.1943-5533.0000335
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发表时间：
2011-12-01
影响因子：
3.2
通讯作者：
Li, Victor C.
中科院分区：
文献类型：
--
作者：
Sahmaran, Mustafa;Ozbay, Erdogan;Li, Victor C.
探讨了大掺量粉煤灰和微细聚乙烯醇(PVA)纤维对工程水泥基复合材料(ECC)耐火性能和微观结构的影响。研究了用两种不同掺量的飞灰替代水泥(占胶凝材料总量的55%和70%)的复合材料。为了确定超细纤维和ECC超高延性的影响，除了PVA纤维外，还制备了成分相似的ECC基质混合物，并进行了耐火试验。将混合物暴露在高达800摄氏度的温度下一小时。然后，根据残余机械性能(强度、应力-应变曲线、挠度和刚度)和质量损失来量化混合物的耐火性能。通过分析PVA纤维和飞灰的微观结构和纤维-基质相互作用随热处理的变化，探讨了PVA纤维和飞灰的作用。用扫描电子显微镜观察了火灾变质前后的微观结构特征，并用压汞测孔仪测定了材料的孔径分布。结果表明，在ECC基质中加入超细PVA纤维，显著提高了ECC的耐火性，消除了ECC的爆炸剥落行为。随着飞灰掺量的增加，ECC混合料的耐火性能进一步提高。DOI：10.1061/(ASCE)MT.1943-5533.0000335。(C)2011年美国土木工程师学会。
This paper discusses the influence of high volumes of fly ash and micro polyvinyl alcohol (PVA) fibers on the fire resistance and microstructure of engineered cementitious composites (ECC). Composites containing two different contents of fly ash as a replacement for cement (55 and 70% by weight of total cementitious materials) are examined. To determine the effects of microfibers and ultrahigh ductility of ECC, ECC matrix mixtures of similar composition except PVA fiber are also produced and tested for the fire resistance. The mixtures are exposed to temperatures up to 800 degrees C for one hour. Fire resistances of the mixtures are then quantified in terms of the residual mechanical properties (strength, stress-strain curve, deflection, and stiffness) and mass loss. The role of PVA fibers and fly ash is discussed through the analysis of microstructure and fiber-matrix interactions as a function of heat treatment. The microstructural characterization is examined before and after exposure to fire deterioration by using scanning electron microscopy and the pore size distribution is obtained by mercury intrusion porosimetry. Results indicate that adding micro PVA fiber to the ECC matrix substantially improves the fire resistance and eliminates the explosive spalling behaviors of the ECC matrix. Fire resistance of ECC mixtures is further improved with the increase of fly ash content. DOI: 10.1061/(ASCE)MT.1943-5533.0000335. (C) 2011 American Society of Civil Engineers.