通过三步碳化强化再生透水混凝土的性能研究

Study on performance of reinforcement ofrecycled pervious concrete by three-step carbonation

为了使用再生细骨料100%替代天然骨料制成再生透水混凝土,通过对再生细骨料烘干碳化、对浆料注碳搅拌、对再生透水混凝土碳化养护三步碳化工艺,起到强化透水混凝土的效果。对透水混凝土试件进行连通孔隙率、抗压强度测试,分析再生细骨料碳化程度、注碳浆体早期强度对透水混凝土力学性能的影响。结果表明:对再生细骨料进行烘干碳化处理,2 h碳化程度达69.05%;碳化再生骨料、碳化养护均可有效提升试件强度,抗压强度分别最大提高88.94%、33.40%,且不会影响试件透水性能;注碳搅拌可吸收固定一部分CO 2,提高试件透水性能和碳化养护效率,但对试件抗压强度产生负面影响,最大降低42.70%,碳化养护后强度仅下降7.0%。

The recycled pervious concrete is composed of recycled fine aggregate,which completely replaces natural aggregate.To enhance the concrete s strength,three steps of carbonization were adopted:drying and carbonizing the recycled fine aggregate,CO 2 mixing slurry and carbonization curing.The connected porosity and compressive strength were investigated to analyze the effects of the recycled fine aggregate s carbonization degree and early strength of CO 2-mixing slurry.The results show that within 2 hours of drying and carbonization,the recycled fine aggregate can achieve a carbonization degree as high as 69.05%.Aggregate carbonization and carbonization curing effectively improve specimen s compressive strength by increasing by 88.94%and 33.4%,respectively,without impacting specimen permeability.Mixing CO 2 in the slurry helps CO 2 fixation while enhancing permeability and increasing efficiency in terms of carbonation curing;however,it negatively affects specimen compressive strength with a maximum reduction rate reaching 42.7%.After undergoing both processes-carbonizing and curing-specimen only experience a slight decrease in compressive strength(7%).