Mwiti Marangu J, Karanja Thiong'o J, Muthengia Wachira J
Department of Chemistry, Kenyatta University, Nairobi, Kenya.
Department of Physical Sciences, University of Embu, Embu, Kenya.
Heliyon. 2018 Aug 20;4(8):e00742. doi: 10.1016/j.heliyon.2018.e00742. eCollection 2018 Aug.
This paper presents findings of an experimental investigation on sodium sulphate (NaSO) activated calcined clay - Portland cement blends in sulphuric acid media. Calcined clays were blended with Ordinary Portland Cement (OPC) at replacement levels of 40% 45% and 50 % by mass of OPC to make blended cement labelled PCC40, PCC45 and PCC50 respectively. Initially, pozzolanicity and setting time tests were conducted. Mortar prisms measuring 40 mm × 40 mm × 160 mm were cast using 0.5M NaSO solution and their compressive strengths determined on the 2, 7, 28 and 90 day of curing. The 28 day cured mortar prisms were subjected to porosity test. Moreover, 5 × 5 × 5 cm mortar cubes were also prepared and their weight and strength loss was taken as a measure of their acid resistivity after an immersion time of 7, 14, 28, 56, 84 and 120 days in 3 % of sulphuric acid at 23 ± 1 °C. OPC, commercial Portland Pozzolana Cement (PPC) and PCC40, PCC45 and PCC50 cement were cast using water and similarly investigated for comparison purposes. The results obtained showed that chemically activated cements exhibited higher pozzolanic activity, lower porosity, shorter setting times and higher resistance to acid attack compared to non-activated cements. However, OPC was found to be non-pozzolanic.
本文介绍了在硫酸介质中对硫酸钠（NaSO）激发的煅烧黏土 - 硅酸盐水泥混合物进行实验研究的结果。将煅烧黏土与普通硅酸盐水泥（OPC）按质量比分别替代OPC的40%、45%和50%进行混合，制成分别标记为PCC40、PCC45和PCC50的混合水泥。首先，进行了火山灰活性和凝结时间测试。使用0.5M的NaSO溶液浇筑尺寸为40mm×40mm×160mm的砂浆棱柱体，并在养护的第2、7、28和90天测定其抗压强度。对养护28天的砂浆棱柱体进行孔隙率测试。此外，还制备了5×5×5cm的砂浆立方体，在23±1°C的3%硫酸中浸泡7、14、28、56、84和120天后，以其重量和强度损失作为耐酸性的衡量指标。使用水浇筑OPC、商业波特兰火山灰水泥（PPC）以及PCC40、PCC45和PCC50水泥，并进行类似的研究以作比较。所得结果表明，与未激发的水泥相比，化学激发水泥表现出更高的火山灰活性、更低的孔隙率、更短的凝结时间以及更高的耐酸侵蚀性。然而，发现OPC没有火山灰活性。
