Flexural strength and elastic modulus of ambient-cured blended low-calcium fly ash geopolymer concrete
Flexural strength and elastic modulus of ambient-cured blended low-calcium fly ash geopolymer concrete
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DOI：
10.1016/j.conbuildmat.2016.11.034
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发表时间：
2017-01-15
影响因子：
7.4
通讯作者：
Sarker, Prabir Kumar
中科院分区：
文献类型：
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作者：
Nath, Pradip;Sarker, Prabir Kumar
飞灰地聚合物是一种新兴的替代粘结剂，对环境影响小，具有提高混凝土施工可持续性的潜力。以往的工作大多考察了高温养护下的粉煤灰基地聚合物混凝土(GPC)的性能。为了推广GPC在现浇混凝土中的应用，本文研究了在常温养护条件下掺入的低钙粉煤灰地聚合物混凝土的性能。用低钙飞灰掺入少量的矿渣、普通硅酸盐水泥或消石灰等外加剂来制备地聚合物混凝土，以提高其早期性能。样品在室内环境(18-23摄氏度和70+/-10%相对湿度)中养护，直到进行测试。结果表明，硬化后的GPC混合料的密度与常重OPC混凝土的密度相近。与对照混凝土相比，外加剂的加入显著提高了混凝土的力学强度。在抗压强度相近的情况下，GPC常温养护混凝土的抗折强度高于OPC混凝土。常温养护的GPC混凝土的弹性模量值往往低于同级配的OPC混凝土。OPC混凝土弹性模数的标准预测和经验公式对GPC并不保守。在此基础上，提出了GPC弹性模量的保守预测公式。(C)2016爱思唯尔有限公司。保留所有权利。
Fly ash geopolymer is an emerging alternative binder with low environmental impact and potential to enhance sustainability of concrete construction. Most previous works examined the properties of fly ash-based geopolymer concrete (GPC) subjected to curing at elevated temperature. To extend the use of GPC in cast-in-situ applications, this paper investigated the properties of blended low-calcium fly ash geopolymer concrete cured in ambient condition. Geopolymer concretes were produced using low calcium fly ash with a small percentage of additive such as ground granulated blast furnace slag (GGBFS), ordinary Portland cement (OPC) or hydrated lime to enhance early age properties. Samples were cured in room environment (18-23 degrees C and 70 +/- 10% relative humidity) until tested. The results show that, density of hardened GPC mixtures is similar to that of normal-weight OPC concrete. Inclusion of additives enhanced the mechanical strengths significantly as compared to control concrete. For similar compressive strength, flexural strength of ambient cured GPC was higher than that of OPC concrete. Modulus of elasticity of ambient cured GPC tend to be lower than that of OPC concrete of similar grade. Prediction of elastic modulus by Standards and empirical equations for OPC concrete were found not conservative for GPC. Thus, an equation for conservative prediction of elastic modulus of GPC is proposed. (C) 2016 Elsevier Ltd. All rights reserved.