Pelisser Giovana, Ferrazzo Suéllen Tonatto, Mota Jonas Duarte, Dos Santos Carolina Pereira, Pelisser Crivian, Rosa Francisco Dalla, Korf Eduardo Pavan
Graduate Program in Environmental Science and Technology - PPGCTA, Federal University of Fronteira Sul, Erechim, RS, 99700-970, Brazil.
Graduate Program in Civil Engineering, Federal University of Rio Grande Do Sul - PPGEC, Porto Alegre, RS, 90035-190, Brazil.
Environ Sci Pollut Res Int. 2023 Mar;30(14):42176-42191. doi: 10.1007/s11356-022-25117-8. Epub 2023 Jan 16.
Rice husk ash (RHA) is an excellent pozzolana and associated with hydrated lime (HL), it becomes an alternative binder to Portland cement in soil stabilization. In the context of waste valorization, waste foundry sand (WFS) and carbide lime (CL) have been investigated in civil construction and environmental geotechnical applications. However, stabilizing WFS with alternative binders to Portland cement represents a large field of research to be explored. This study evaluated the stabilization of WFS with a binder based on RHA and CL, compared to the use of RHA-HL. An experimental design was carried out to evaluate the influence of different dry-specific weights (12.00, 12.75, and 13.50 kN/m), RHA contents (10%, 20%, and 30%), and curing times (28, 60, and 90 days) under unconfined compressive strength (UCS). UCS results were submitted to statistical analysis and correlated to the porosity/binder content index (η/B). Healing capacity, mineralogy, microstructure, and leaching of metals from mixtures of interest were evaluated. The results showed that higher specific weights and higher percentages of RHA promoted better strength. The η/B index proved to be an adequate parameter to assess the UCS of WFS-RHA mixtures with different limes (CL and HL), lower porosity, and higher binder content leading to higher strengths. The mixture's mineralogy and microscopy showed the formation of cementing gels, corroborating the strength gains. WFS stabilized with both binders (RHA-CL and RHA-HL) presented satisfactory environmental performance, allowing the immobilization of metals in the waste compositions.
稻壳灰（RHA）是一种优质的火山灰，与熟石灰（HL）结合后，成为土壤稳定化中波特兰水泥的替代粘结剂。在废物增值利用的背景下，废铸造砂（WFS）和电石渣（CL）已在民用建筑和环境岩土工程应用中得到研究。然而，用波特兰水泥的替代粘结剂稳定WFS是一个有待探索的广阔研究领域。本研究评估了基于RHA和CL的粘结剂对WFS的稳定化效果，并与RHA-HL的使用效果进行了比较。进行了一项实验设计，以评估不同干重度（12.00、12.75和13.50 kN/m）、RHA含量（10%、20%和30%）以及养护时间（28、60和90天）对无侧限抗压强度（UCS）的影响。UCS结果进行了统计分析，并与孔隙率/粘结剂含量指数（η/B）相关联。评估了感兴趣混合物的愈合能力、矿物学、微观结构和金属浸出情况。结果表明，较高的重度和较高的RHA百分比可促进更好的强度。η/B指数被证明是评估不同石灰（CL和HL）、较低孔隙率和较高粘结剂含量导致更高强度的WFS-RHA混合物UCS的合适参数。混合物的矿物学和显微镜观察显示了胶凝凝胶的形成，证实了强度的提高。用两种粘结剂（RHA-CL和RHA-HL）稳定的WFS表现出令人满意的环境性能，使废物成分中的金属得以固定。
