Lekhya Arava, Kumar N Senthil
School of Civil Engineering, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India.
Heliyon. 2024 Oct 22;10(22):e39678. doi: 10.1016/j.heliyon.2024.e39678. eCollection 2024 Nov 30.
Conventional cement production is a major source of CO emissions. As a result, there is an increasing emphasis on finding sustainable alternatives for cement and their appropriate proportion in concrete. This investigation explores the optimization of supplementary cementitious materials (SCM) like ultrafine fly ash (UFFA) and silica fume (SF) content in high-performance concrete (HPC). The study includes the production of binary and ternary concrete mixes by replacing Portland cement with UFFA and SF at 0, 5, 10, and 15 %. A total of 16 mixes were prepared and evaluated in three stages. The first stage involved assessing the mechanical properties using compressive strength test and non-destructive test (NDT) results at various intervals. The second stage included durability tests, such as water absorption, volume of voids, and water permeability tests. In the third stage, characterization studies like XRD, TGA, and FTIR were conducted on the finalized mixes at 28 and 90 day intervals to find the optimum mix. The NDT findings revealed that all HPC mixes had superior quality, with a velocity of more than 5 km/s. From the test results, the ternary mix U10S15 exhibited superior compressive strengths of 104.28 MPa at 90 days of curing. The durability test results also demonstrated that the blend U10S15 showed a lower water absorption of 1.26 %, indicating a 44.9 % reduction in water absorption with extended curing. The FTIR and TGA analysis of HPC mixes demonstrated that blending the optimal amounts of UFFA and SF results in a dense microstructure. The mixture U10S15 exhibits a considerable peak shift from 950 to 980 cm⁻. XRD peaks confirmed the presence of extra hydration peaks in blended specimens at 28° of 2θ. The optimized HPC mix containing 10 % UFFA and 15 % SF (U10S15) is appropriate for water-retaining structures due to its high strength, lower permeability, and higher particle packing effect.
传统水泥生产是二氧化碳排放的主要来源。因此，人们越来越重视寻找水泥的可持续替代品及其在混凝土中的合适比例。本研究探讨了高性能混凝土（HPC）中补充胶凝材料（SCM）如超细粉煤灰（UFFA）和硅灰（SF）含量的优化。该研究包括通过用0%、5%、10%和15%的UFFA和SF替代波特兰水泥来生产二元和三元混凝土混合物。总共制备了16种混合物，并分三个阶段进行评估。第一阶段涉及使用抗压强度试验和不同时间间隔的无损检测（NDT）结果来评估力学性能。第二阶段包括耐久性试验，如水吸收、孔隙体积和水渗透性试验。在第三阶段，对最终混合物在28天和90天间隔进行XRD、TGA和FTIR等表征研究，以找到最佳混合物。无损检测结果表明，所有高性能混凝土混合物质量都很高，声速超过5 km/s。从试验结果来看，三元混合物U10S15在养护90天时表现出104.28 MPa的优异抗压强度。耐久性试验结果还表明，混合物U10S15的吸水率较低，为1.26%，表明随着养护时间延长，吸水率降低了44.9%。高性能混凝土混合物的FTIR和TGA分析表明，混合最佳量的UFFA和SF会导致致密的微观结构。混合物U10S15在950至980 cm⁻处有明显的峰位移。XRD峰证实了在2θ为28°的混合试样中存在额外的水化峰。含有10% UFFA和15% SF的优化高性能混凝土混合物（U10S15）因其高强度、低渗透性和高颗粒堆积效应，适用于挡水结构。
