Wang Jialei, Jiang Feifei, Zhou Juan, Mao Zhongyang
School of Civil Engineering and Architecture, NingboTech University, Ningbo 315100, China.
School of Civil Engineering, Nantong Institute of Technology, Nantong 226000, China.
Materials (Basel). 2024 Oct 16;17(20):5058. doi: 10.3390/ma17205058.
Fully utilizing solid waste as supplementary cementitious materials (SCMs) while ensuring the mechanical properties of cement-based materials is one of the pathways for carbon reduction in the cement industry. Understanding the effects of the two solid wastes-limestone powder (LP) and rice husk ash (RHA) on the mechanical properties of cement-based materials is of great significance for their application in concrete. This study investigates the impact of LP and RHA on the strength of cement mortar at various ages and the microhardness of hardened cement paste. The results suggest that two materials have a certain synergistic effect on the mechanical properties of the cementitious materials. The addition of RHA effectively addresses the issues of slow strength development, insufficient late-stage strength of the cementitious material, and the low strength blended with a large amount of LP, while a suitable amount of LP can promote the strength increase in the cement-RHA system. Based on the comprehensive analysis of compressive strength and microhardness, the optimal solution for achieving high mechanical properties in composite cementitious materials is to use 10% each of LP and RHA, resulting in a 9.5% increase in 28 d strength compared to a pure cement system. The higher the content of LP, the greater the increase caused by 10% RHA in compressive strength of the composite system, which makes the strength growth rate of cementitious material mixed with 10% LP at 3-56 d 62.1%. When the LP content is 20% and 30%, the addition of 10% RHA increases the 28 d strength by 44.8% and 38.8%, respectively, with strength growth rates reaching 109.8% and 151.1% at 3-56 d.
在确保水泥基材料力学性能的同时充分利用固体废弃物作为辅助胶凝材料（SCMs）是水泥行业碳减排的途径之一。了解两种固体废弃物——石灰石粉（LP）和稻壳灰（RHA）对水泥基材料力学性能的影响对于它们在混凝土中的应用具有重要意义。本研究调查了LP和RHA对不同龄期水泥砂浆强度以及硬化水泥浆体显微硬度的影响。结果表明，两种材料对胶凝材料的力学性能具有一定的协同作用。RHA的加入有效解决了胶凝材料强度发展缓慢、后期强度不足以及与大量LP混合时强度较低的问题，而适量的LP可以促进水泥 - RHA体系强度的提高。基于抗压强度和显微硬度的综合分析，在复合胶凝材料中实现高力学性能的最佳方案是使用10%的LP和10%的RHA，与纯水泥体系相比，28 d强度提高了9.5%。LP含量越高，10%的RHA对复合体系抗压强度的提高幅度越大，使得含10%LP的胶凝材料在3 - 56 d的强度增长率为62.1%。当LP含量为20%和30%时，加入10%的RHA分别使28 d强度提高44.8%和38.8%，在3 - 56 d强度增长率分别达到109.8%和151.1%。
