Department of Civil Engineering, Faculty of Engineering, Thammasat University, Rangsit Campus, Khlong Luang, Pathumthani 12121, Thailand.
J Environ Manage. 2011 Jan;92(1):59-66. doi: 10.1016/j.jenvman.2010.08.007. Epub 2010 Sep 21.
In this study, black rice husk ash (BRHA) from a rice mill in Thailand was ground and used as a partial cement replacement. The durability of conventional concretes with high water-binder ratios was investigated including drying shrinkage, autogenous shrinkage, depth of carbonation, and weight loss of concretes exposed to hydrochloric (HCl) and sulfuric (H(2)SO(4)) acid attacks. Two different replacement percentages of cement by BRHA, 20% and 40%, and three different water-binder ratios (0.6, 0.7 and 0.8) were used. The ratios of paste volume to void content of the compacted aggregate (γ) were 1.2, 1.4, and 1.6. As a result, when increasing the percentage replacement of BRHA, the drying shrinkage and depth of carbonation reaction of concretes increased. However, the BRHA provides a positive effect on the autogenous shrinkage and weight loss of concretes exposed to hydrochloric and sulfuric acid attacks. In addition, the resistance to acid attack was directly varied with the (SiO(2) + Al(2)O(3) + Fe(2)O(3))/CaO ratio. Results show that ground BRHA can be applied as a pozzolanic material and also improve the durability of concrete.
在这项研究中，泰国一家碾米厂的黑米壳灰（BRHA）经过研磨后被用作部分替代水泥。研究了高水胶比的普通混凝土的耐久性，包括干燥收缩、自收缩、碳化深度和暴露于盐酸（HCl）和硫酸（H₂SO₄）酸侵蚀的混凝土的重量损失。使用了两种不同的 BRHA 替代水泥的百分比，20%和 40%，以及三种不同的水胶比（0.6、0.7 和 0.8）。压实骨料的浆体体积与空隙含量比（γ）为 1.2、1.4 和 1.6。结果表明，随着 BRHA 替代百分比的增加，混凝土的干燥收缩和碳化反应深度增加。然而，BRHA 对暴露于盐酸和硫酸侵蚀的混凝土的自收缩和重量损失有积极影响。此外，耐酸侵蚀性能直接随（SiO₂+Al₂O₃+Fe₂O₃）/CaO 比值而变化。结果表明，研磨后的 BRHA 可作为火山灰材料应用，并提高混凝土的耐久性。
