无砟轨道道床板混凝土抗裂性能-碳排放-成本综合评价研究OA

Reducing the risk of early-age cracking in track bed slab concrete is a critical issue in the application of double block ballastless tracks.However,existing methods for improving the crack resistance of track bed slab concrete often overlook the impacts on carbon emission and economic efficiency.To address this,this study proposed a low-shrinkage,high-crack-resistance track bed slab concrete,which incorporated low heat cement combined with shrinkage-reducing admixture,expansive agent,and fiber.Cracking factor η was defined as the ratio of the maximum tensile stress σ to the tensile strength ft.From life cycle assessment,the carbon emission amount of concrete with different mix proportion was compared.Finally,a multidimensional comprehensive evaluation of cracking factor,modification cost,and carbon emission amount of track bed slab concrete was conducted using entropy-analytic hierarchy process(AHP).The results show that the optimal mix proportion consists of low heat cement combined with 2%(mass fraction)shrinkage-reducing admixture,8%(mass fraction)expansive agent,and 0.3%(mass fraction)fiber.Compared with conventional track bed slab concrete,the optimal concrete mix proportion reduces the cracking risk by approximately 80%,and the raw material-related CO2 emission reduces by 11.53 t per kilometer of track bed.This research has guiding significance for the mix proportion design of low-carbon and high-crack-resistance track bed slab concrete and the comprehensive evaluation of cement-based materials properties,environmental and economic benefits.