Physical and pozzolanic action of mineral additions on the mechanical strength of high-performance concrete
Physical and pozzolanic action of mineral additions on the mechanical strength of high-performance concrete
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DOI：
10.1016/s0958-9465(01)00057-9
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发表时间：
2003-01-01
影响因子：
10.5
通讯作者：
Moraes, R
中科院分区：
文献类型：
--
作者：
Isaia, GC;Gastaldini, ALG;Moraes, R
当添加到硅酸盐水泥中时，polzzolans起着重要的作用，因为它们通常会增加混凝土结构的机械强度和耐久性。在胶凝膏体微观结构中最重要的影响是由火山灰反应（PE）引起的颗粒尺寸减小所产生的孔隙结构的变化，以及细颗粒的作用（物理或填充效应）对孔隙和空隙的阻塞。很少有已发表的研究量化了这两种影响。本研究测试了12种混凝土混合物：一种是波特兰水泥（对照），九种是粉煤灰、稻壳灰和石灰石填料替代水泥的12.5%、25%和50%；两种分别为（12.5 + 12.5）%和（25 + 25）%的粉煤灰和稻壳灰。水胶比分别为0.35、0.50和0.65。试样的抗压强度以MPa / kg水泥计算。同时测定了氢氧化钙和结合水的剩余含量。结果表明：随着矿物添加量的增加，混合料的火山灰效应和物理效应均有所增强，添加量在91 d后高于添加量在28 d后。对比相同强度值（35 MPa和65 MPa）的结果，填料效应（FE）大于火山灰效应（pozzolanic effect）。稻壳灰分在25%及以上的二元和三元混合物中PE较强。2003爱思唯尔科学有限公司版权所有。
Pozzolans play an important role when added to Portland cement because they usually increase the mechanical strength and durability of concrete structures. The most important effects in the cementitious paste microstructure are changes in pore structure produced by the reduction in the grain size caused by the pozzolanic reactions pozzolanic effect (PE) and the obstruction of pores and voids by the action of the finer grains (physical or filler effect). Few published investigations quantify these two effects. Twelve concrete mixtures were tested in this study: one with Portland cement (control), nine mixtures with 12.5%, 25% and 50% of replacement of cement by fly ash, rice husk ash and limestone filler; two with (12.5 + 12.5)% and (25 + 25)% of fly ash and rice husk ash. All the mixtures were prepared with water/binder ratios of 0.35, 0.50, and 0.65. The compressive strength for the samples was calculated in MPa per kg of cement. The remaining contents of calcium hydroxide and combined water were also tested. The results show that the pozzolanic and physical effects have increased as the mineral addition increased in the mixture, being higher after 91 days than after 28 days. When the results for the same strength values are compared (35 and 65 MPa), it was observed that the filler effect (FE) increased more than the pozzolanic effect. The PE was stronger in the binary and ternary mixtures prepared with rice husk ash in proportions of 25% or higher. (C) 2003 Elsevier Science Ltd. All rights reserved.