建筑垃圾再生泡沫混凝土性能及其成孔机理研究

Study on performance and pore-forming mechanism of recycled foam concrete from construction waste

再生砂粉的高效利用是近年来建筑垃圾资源化利用领域的研究难点与热点,以建筑垃圾再生砂粉为原料制备再生泡沫混凝土(RFC),研究了密度等级、砂灰比等因素对RFC性能的影响。结果表明,在水料比为0.25,砂灰比为1时,RFC工作性能相对较好。随着密度等级的降低、砂灰比的提高,RFC抗压强度均呈现下降趋势。与标准砂制备的泡沫混凝土对比,实验制得的RFC强度为标准砂泡沫混凝土强度的50%~65%。通过分析RFC孔结构形貌发现,随着密度等级的增大,在浆体束缚力作用下RFC孔径减小、气孔圆度得到改善、抗压强度提高;随着砂灰比的增大,气孔孔径倾向于减小、并形成连通孔的趋势,从而使基体内部结构承载力下降,从成孔机理层面揭示了RFC力学性能的变化规律。

The efficient utilization of recycled fine aggregate has always been the hot and difficult issue in recent years.In this paper,recycled foam concrete(RFC)was prepared with recycled fine aggregate from construction waste.The influence of differ-ent factors on the performance of RFC has been studied,including density levels and sand-cement ratios.The results show RFC fluidity is the best under condition of water-material ratio 0.25,and sand-cement ratio 1.And the compressive strength of RFC decreases with the decrease of density grade and the increase of sand-cement ratio.Compared with foamed concrete prepared with standard sand,the compressive strength of RFC is about 50%~65%of foam concrete prepared with standard sand.Analyzing the morphology of RFC pore structure,we find that with the increase of density grade,the RFC aperture decreases,and the compressive strength is improved.With the increase of sand-cement ratio,the pore aperture tends to decrease and form connected holes,which reduces the bearing capacity of RFC,and reveals the mechanical properties of RFC from the pore-forming mechanism.