保水性再生骨料透水混凝土制备及其蒸发冷却效果研究
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摘要
研究了硅灰掺量、砂率及天然骨料替代率对再生骨料透水混凝土抗压强度的改善效果,并在此基础上制备出抗压强度较高的再生骨料透水混凝土,再掺加保水材料以制备保水性再生骨料透水混凝土并研究其蒸发冷却效果。结果表明,提高硅灰掺量可增大拌和浆体量并改善界面过渡区的微观结构,提高砂率可显著增加拌和浆体量,而提高天然骨料替代率则改善了骨料颗粒级配,因此三种措施均能有效提高再生骨料透水混凝土的抗压强度;当硅灰掺量为7.5%、砂率为10%、天然骨料替代率为20%时可制备出28 d抗压强度达27.3 MPa的再生骨料透水混凝土,此时掺加保水材料制备保水性再生骨料透水混凝土,当保水材料掺量分别为3%、5%及7%时,试样28 d抗压强度将分别降低了35.9%、51.6%及57.1%。其中,保水材料掺量为3%的透水混凝土具有持续有效的蒸发冷却效果,而保水材料掺量为5%及7%的透水混凝土则仅具有显著的早期蒸发冷却效果。
To prepare high strength recycled aggregate pervious concrete(RAPC), a series of measures including the content of silica fume, the sand ratio and the replacement rate of natural aggregate were conducted to improve the compressive strength of RAPC.The water-retention type RAPC was prepared by adding water retention material(WRM) and its evaporative cooling effect was also studied.The results show that the adding of silica fume increase the volume of paste and modify the microstructure of aggregate-paste interface transition zone.Meanwhile, increasing the sand ratio can increase the volume of mixing slurry significantly.While, increasing the replacement rate of natural aggregate can improve the particle gradation.Therefore,these three measures can all improve the compressive strength of RAPC, As a result.RAPC with compressive strength of 27.3 MPa after curing 28 d can be achieved when the content of silica fume is 7.5%, sand ratio is 10% and natural aggregate replacement rate is 20%.Then, three water-retention type RAPCs with WRM of 3%, 5% and 7% were prepared and the compressive strength of these three samples were reduced by 35.9%, 51.6% and 57.1 %.Among them, sample with 3% WRM has sustained and effective evaporative cooling effect, and the other two samples only have early evaporative cooling effect.
To prepare high strength recycled aggregate pervious concrete(RAPC), a series of measures including the content of silica fume, the sand ratio and the replacement rate of natural aggregate were conducted to improve the compressive strength of RAPC.The water-retention type RAPC was prepared by adding water retention material(WRM) and its evaporative cooling effect was also studied.The results show that the adding of silica fume increase the volume of paste and modify the microstructure of aggregate-paste interface transition zone.Meanwhile, increasing the sand ratio can increase the volume of mixing slurry significantly.While, increasing the replacement rate of natural aggregate can improve the particle gradation.Therefore,these three measures can all improve the compressive strength of RAPC, As a result.RAPC with compressive strength of 27.3 MPa after curing 28 d can be achieved when the content of silica fume is 7.5%, sand ratio is 10% and natural aggregate replacement rate is 20%.Then, three water-retention type RAPCs with WRM of 3%, 5% and 7% were prepared and the compressive strength of these three samples were reduced by 35.9%, 51.6% and 57.1 %.Among them, sample with 3% WRM has sustained and effective evaporative cooling effect, and the other two samples only have early evaporative cooling effect.
引文
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[3] Li X. Recycling and reuse of waste concrete in China:Part1. Material behaviour of recycled aggregate concrete[J].Resources, Conservation and Recycling, 2008. 53(1-2):36-44.
[4]史才军,曹芷杰,谢昭彬.再生混凝土力学性能的研究进展[J].材料导报,2016, 30(23):96-103.
[5]陈守开,杨晴,刘秋常,等.再生骨料透水混凝土强度及透水性能试验[J].农业工程学报,2017, 33(15).141-146.
[6]陈伟娇.水谷章夫.开粒度与保水性沥青路面铺装材料表面蒸发冷却效果的比较[J].建筑科学,2011, 27(4):56-59.
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