钢渣加速碳化制品的耐高温性能研究

为开发钢渣用于高温环境的潜力,最大限度地提高钢渣的综合利用率,通过强度试验、热重分析(TGA)、X射线衍射分析(XRD)、扫描电子显微镜分析(SEM)等测试手段探讨了钢渣加速碳化制品承受不同高温后的抗压强度、矿物相演变和微观结构。结果表明:钢渣加速碳化制品在200~600 ℃范围内的高温处理下,抗压强度得到提高,在400 ℃时达到最大值,为72.4 MPa,较初始强度提高20.5%,钢渣中硅酸钙在高温下进一步发生水化,其水化产物增强了基质连接。当温度达到800 ℃时,钢渣性能发生劣化,强度降低了90.7%,碳酸钙质量分数由24.1%降低至1.6%,而总质量损失可达19.67%,吸水率大幅度提高,且出现贯通试块的裂缝。钢渣加速碳化制品与普通水泥基材料相比,耐高温性能有所提升,但在800 ℃时并无明显优势。

High Temperature Resistance of Accelerated Carbonated Steel Slag Blocks

In order to develop steel slag for high temperature environments and improve the comprehensive utilization rate as much as possible, compressive strength, mineral phases, and microstructure of accelerated carbonated steel slag blocks cured with different high temperatures were investigated in this study by strength test, TGA, XRD and SEM. The results show that the compressive strength of accelerated carbonated steel slag blocks is improved when exposed to high temperature between 200 ℃ to 600 ℃, and the highest compressive strength of 72.4 MPa is obtained at 400 ℃, which is 20.5% higher than the initial compressive strength. The content of calcium silicate at 400 ℃ is reduced, C-S-H net structure is observed, which confirmed the further hydration of calcium silicate. The hydration product enhances the matrix connection, resulting in strength improvement. The performance of steel slag degrades at 800 ℃ and the strength reduces 90.7% of initial strength. The mass fraction of calcium carbonate reduces from 24.1% to 1.6%. The total mass loss reaches 19.67% and the water absorption improves significantly. Cracks through the blocks are also investigated. The high temperature resistance of accelerated carbonated steel slag blocks is better than cement-based materials, but the advantage is not obvious when the temperature reaches 800 ℃.