Sinkhonde David, Onchiri Richard Ocharo, Oyawa Walter Odhiambo, Mwero John Nyiro
Department of Civil and Construction Engineering, Pan African University Institute for Basic Sciences, Technology and Innovation, Nairobi, Kenya.
Department of Building and Civil Engineering, Technical University of Mombasa, Mombasa, Kenya.
Heliyon. 2023 Jun 21;9(6):e17514. doi: 10.1016/j.heliyon.2023.e17514. eCollection 2023 Jun.
The existing literature shows that rubberised concrete suffers from reduced mechanical properties when it is compared with normal density non-rubberised concrete. This is due to the underlying reduced bonding between tire rubber and other concrete ingredients. The massive sulfuric acid attack in rubberised concrete must have additionally discouraged researchers from attempts to assess the phenomenon of improving performance of rubberised concrete. A research was undertaken to compare the properties of concrete mixes containing tire rubber replacing coarse aggregate and waste clay brick powder (WCBP) replacing cement exposed to sulfuric acid and cured in water. Concrete cubes and cylinders of concrete grades of 20 MPa, 25 MPa and 30 MPa were immersed in 5% sulfuric acid solution up to 90 days following moist curing of 27 days. Other concrete cubes and cylinders were cured in water for comparison. The compressive strength findings indicated that all the specimens exposed to sulfuric acid had lost more than 57% of their compressive strengths after 90 days with reference to the corresponding samples cured in water. In contrast, out of all concrete mixes investigated for all concrete grades, never were the split tensile strength losses of the specimens exposed to sulfuric acid greater than 43.1% compared with those cured in water. In each exposure condition, concrete mixes with 5% WCBP showed slight improvements in compressive and split tensile strengths in contrast with the conventional concrete mixes. Visual inspection of the specimens illustrated depositions of flaky or white substances on the outer layers of specimens exposed to sulfuric acid compared with specimens cured in water. Moreover, the split tensile strengths of specimens were not severely affected with exposure to sulfuric acid in comparison with compressive strengths. Eventually, the research identified the existence of WCBP in rubberised concrete as a promising criterion of minimising strength losses of rubberised concrete.
现有文献表明，与普通密度的非橡胶混凝土相比，橡胶混凝土的力学性能会降低。这是由于轮胎橡胶与其他混凝土成分之间的粘结力下降所致。橡胶混凝土中大量的硫酸侵蚀必定也阻碍了研究人员评估橡胶混凝土性能改善现象的尝试。开展了一项研究，以比较含有替代粗骨料的轮胎橡胶和替代水泥的废粘土砖粉（WCBP）的混凝土混合料在暴露于硫酸并在水中养护后的性能。20MPa、25MPa和30MPa混凝土等级的混凝土立方体和圆柱体在27天潮湿养护后，浸泡在5%的硫酸溶液中长达90天。其他混凝土立方体和圆柱体在水中养护以作比较。抗压强度测试结果表明，所有暴露于硫酸的试件在90天后，相对于在水中养护的相应试件，其抗压强度损失超过了57%。相比之下，在所有研究的混凝土等级的所有混凝土混合料中，暴露于硫酸的试件的劈裂抗拉强度损失与在水中养护的试件相比，从未超过43.1%。在每种暴露条件下，与传统混凝土混合料相比，含有5%WCBP的混凝土混合料的抗压强度和劈裂抗拉强度略有提高。对试件的目视检查表明，与在水中养护的试件相比，暴露于硫酸的试件外层有片状或白色物质沉积。此外，与抗压强度相比，试件的劈裂抗拉强度受硫酸暴露的影响并不严重。最终，该研究确定橡胶混凝土中WCBP的存在是使橡胶混凝土强度损失最小化的一个有前景的标准。
