Strength properties and micro-structural properties of concrete containing coal bottom ash as partial replacement of fine aggregate
Strength properties and micro-structural properties of concrete containing coal bottom ash as partial replacement of fine aggregate
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DOI：
10.1016/j.conbuildmat.2013.09.026
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发表时间：
2014-01
影响因子：
7.4
通讯作者：
Malkit Singh;R. Siddique
中科院分区：
文献类型：
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作者：
Malkit Singh;R. Siddique
燃煤火力发电厂是粉煤灰的主要生产来源。在炉底收集的煤灰称为炉底灰（CBA）。本研究的目的是探索利用煤灰作为混凝土中部分取代细骨料（砂）的可能性。对新拌和硬化后的粉煤灰混凝土的性能进行了试验研究。研究了粉煤灰部分或全部取代河砂配制的混凝土的容重、抗压强度、劈裂抗拉强度、弹性模量和微观结构等性能，并与普通混凝土进行了比较。研究了用粉煤灰代替河砂后新拌混凝土的泌水损失和工作性。试验结果表明，在水灰比一定的情况下，用煤灰代替河砂，混凝土的工作性和泌水损失降低。底灰混凝土在养护28天后的抗压强度没有受到很大的影响。但养护90 d后，底灰混凝土的抗压强度超过常规混凝土。各龄期混凝土劈裂抗拉强度均有所提高。在所有养护龄期，弹性模量都随着煤灰的使用而降低。SEM和XRD研究表明，掺入煤底灰后，混凝土中C-S-H凝胶结构的整体性稍差，钙矾石的总强度没有发生变化。
The coal fired thermal power plants are the main source of production of coal ash. The coal ash collected at the bottom of the furnace is called coal bottom ash (CBA). The objective of the present research work was to explore the possibility of utilization of coal bottom ash as partial replacement of fine aggregate (sand) in concrete. Experimental tests were performed to evaluate the properties of fresh and hardened concrete containing coal bottom ash. The properties such as unit weight, compressive strength, and splitting tensile strength, modulus of elasticity and microstructure of concrete incorporating coal bottom ash in partial or full replacement of river sand were examined and compared with those of conventional concrete. Water loss by bleeding and workability of fresh concrete after replacing river sand with coal bottom ash were also examined. The test results of this research work indicate that at fixed water cement ratio, workability and loss of water from bleeding decreased with the use of coal bottom ash as a replacement of river sand in concrete. Compressive strength of bottom ash concrete at the curing age of 28 days was not strongly affected. However, after 90 days of curing age, compressive strength of bottom ash concrete surpassed that of conventional concrete. Splitting tensile strength of concrete improved at all the curing ages. The modulus of elasticity decreased with the use of coal bottom ash at all the curing ages. SEM and XRD studies indicated that the C–S–H gel structure was slightly less monolithic than that of control concrete and total intensity of ettringite was not changed with the addition of coal bottom ash in concrete.