Effects of NaOH Concentrations on Properties of the Thermal Power Plant Ashes-Bricks by Alkaline Activation
来源期刊：Journal Of Wuhan University Of Technology Materials Science Edition2020年第1期
论文作者：Ngo Si-Huy Le Thi Thanh-Tam Huynh Trong-Phuoc
文章页码：131 - 139
摘 要：The use of the thermal power plant ashes including fly ash（FA） and bottom ash（BA） for producing unfired building bricks（UBB） using sodium hydroxide（Na OH） solution as an alkaline activator was investigated. A low applied forming pressure of 0.5 MPa and various Na OH concentrations of 5, 8, 10, and 12 M were used for the preparation of brick samples with different solution-to-binder（S/B） ratios of 0.35 and 0.40. The bricks were subjected to various test programs with reflecting the effect of both Na OH concentrations and S/B ratios on the brick’s properties. The compressive strength, unit weight, ultrasonic pulse velocity, and thermal conductivity of bricks increased with increasing Na OH concentration, whereas the contrary trend was found with increasing S/B ratio. Also, the water absorption of bricks was observed to reduce with increasing Na OH concentration and decreasing S/B ratio. As the results, the combined utilization of both low forming pressure and coal power plant ashes can produce the UBBs with low unit weight, low heat conductivity, and acceptable strength and water absorption rate as stipulated by TCVN 6477-2016. Furthermore, the outcomes of chemical analysis and microstructure observation also demonstrate that a high concentration of the Na OH promoted the geopolymerization process. Notably, the use of Na OH solution of either 10 M or above is recommended for the production of UBBs, which are classified as grade M5.0 or higher.
Ngo Si-Huy1，Le Thi Thanh-Tam1，Huynh Trong-Phuoc2
1. Department of Engineering and Technology, Hong Duc University2. Department of Rural Technology, College of Rural Development, Can Tho University
摘 要：The use of the thermal power plant ashes including fly ash（FA） and bottom ash（BA） for producing unfired building bricks（UBB） using sodium hydroxide（Na OH） solution as an alkaline activator was investigated. A low applied forming pressure of 0.5 MPa and various Na OH concentrations of 5, 8, 10, and 12 M were used for the preparation of brick samples with different solution-to-binder（S/B） ratios of 0.35 and 0.40. The bricks were subjected to various test programs with reflecting the effect of both Na OH concentrations and S/B ratios on the brick’s properties. The compressive strength, unit weight, ultrasonic pulse velocity, and thermal conductivity of bricks increased with increasing Na OH concentration, whereas the contrary trend was found with increasing S/B ratio. Also, the water absorption of bricks was observed to reduce with increasing Na OH concentration and decreasing S/B ratio. As the results, the combined utilization of both low forming pressure and coal power plant ashes can produce the UBBs with low unit weight, low heat conductivity, and acceptable strength and water absorption rate as stipulated by TCVN 6477-2016. Furthermore, the outcomes of chemical analysis and microstructure observation also demonstrate that a high concentration of the Na OH promoted the geopolymerization process. Notably, the use of Na OH solution of either 10 M or above is recommended for the production of UBBs, which are classified as grade M5.0 or higher.
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