Chatveera B, Lertwattanaruk P
Department of Civil Engineering, Faculty of Engineering, Thammasat University, Rangsit Campus, Khlong Luang, Pathumthani 12121, Thailand.
J Environ Manage. 2009 Mar;90(3):1435-41. doi: 10.1016/j.jenvman.2008.09.001. Epub 2008 Nov 12.
In this paper, black rice husk ashes (BRHAs), which are agrowastes from an electricity generating power plant and a rice mill, were ground and used as a partial cement replacement. The durability of mortars under sulfate attack including expansion and compressive strength loss were investigated. For parametric study, BRHA were used as a Portland cement Type 1 replacement at the levels of 0%, 10%, 30%, and 50% by weight of binder. The water-to-binder ratios were 0.55 and 0.65. For the durability of mortar exposed to sulfate attack, 5% sodium sulfate (Na2SO4) and magnesium sulfate (MgSO4) solutions were used. As a result, when increasing the percentage replacement of BRHA, the expansion and compressive strength loss of mortar decreased. At the replacement levels of 30% and 50% of BRHA, the expansion of the mortars was less than those mixed with sulfate-resistant cement. However, the expansion of the mortars exposed to Na2SO4 was more than those exposed to MgSO4. Increasing the replacement level of BRHA tends to reduce the compressive strength loss of mortars exposed to Na2SO4 attack. In contrary, under MgSO4 attack, when increasing the replacement level of BRHA, the compressive strength loss increases from 0% to 50% in comparison to Portland cement mortar. Results show that ground BRHA can be applied as a pozzolanic material to concrete and also improve resistance to sodium sulfate attack, but it can impair resistance to magnesium sulfate attack.
在本文中，来自发电厂和碾米厂的农业废弃物黑米稻壳灰（BRHAs）被研磨并用作水泥的部分替代品。研究了砂浆在硫酸盐侵蚀下的耐久性，包括膨胀和抗压强度损失。为了进行参数研究，BRHA被用作Ⅰ型波特兰水泥的替代品，替代量按胶凝材料重量计分别为0%、10%、30%和50%。水胶比为0.55和0.65。对于暴露于硫酸盐侵蚀的砂浆耐久性研究，使用了5%的硫酸钠（Na2SO4）和硫酸镁（MgSO4）溶液。结果表明，随着BRHA替代百分比的增加，砂浆的膨胀和抗压强度损失降低。在BRHA替代量为30%和50%时，砂浆的膨胀小于掺有抗硫酸盐水泥的砂浆。然而，暴露于Na2SO4的砂浆的膨胀大于暴露于MgSO4的砂浆。增加BRHA的替代量往往会降低暴露于Na2SO4侵蚀的砂浆的抗压强度损失。相反，在MgSO4侵蚀下，与波特兰水泥砂浆相比，当BRHA替代量从0%增加到50%时，抗压强度损失增加。结果表明，磨细的BRHA可作为火山灰质材料应用于混凝土中，还可提高抗硫酸钠侵蚀能力，但会削弱抗硫酸镁侵蚀能力。
