纳米碳化硅改性水玻璃对再生骨料的强化作用机制研究
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摘要
为了进一步强化再生骨料、改善再生骨料混凝土的性能,研究了纳米碳化硅改性水玻璃对再生骨料的强化效果,并分析了作用机制。结果表明,纳米碳化硅改性水玻璃对再生骨料的强化作用明显,但会受水玻璃浓度和纳米碳化硅掺量的影响。水玻璃浓度增大,经水玻璃强化处理的再生骨料表观密度和堆积密度先增大后减小,吸水率逐渐降低,含水率逐渐增加,压碎指标先减小后增大;经水玻璃溶液+纳米碳化硅复合强化的再生骨料随着纳米碳化硅加入量的增加,表观密度和堆积密度先增大后减小,吸水率和含水率均先降低后增大,压碎指标先减小后增大。经浓度为30%的水玻璃溶液+0.75%纳米碳化硅浸泡强化的再生骨料,孔隙和裂缝被改性水玻璃填充,再生骨料表面均匀,综合性能较好,拌制的再生混凝土28 d抗压强度较未处理的再生骨料拌制的混凝土提高约45%,较天然骨料拌制的混凝土低约10%。
In order to intensify the recycled aggregate and improve the properties of recycled concrete further, the strengthening effect and mechanism of sodium silicate modified by nano-SiC on the recycled aggregate concrete were studied. The results show that the strengthening effect is obvious,but it is influenced by concentration of sodium silicate and addition of nano-SiC. As the concentration of water glass is increased, the apparent density and bulk density of the recycled aggregate treated with water glass are firstly increased, the water absorption is gradually reduced, the water content is gradually increased, and the crushing index is increased firstly. With the increase of nano-SiC content, the apparent density and bulk density of recycled aggregate reinforced by nano-SiC solution increased firstly and then decreased, the water absorption and water content decreased first and then increased, and the crushing index decreased first and then increased. The properties of the recycled aggregate which intensified by modified sodium silicate solution with a concentration of 30% and addition of 0.75% nano-SiC are relatively good. The surface of recycled aggregate is even. Pores and cracks are filled with modified sodium silicate. The 28 d compressive strength of corresponding recycled concrete is about 45% higher than the recycled concrete when the recycled aggregate without any treatment, but it is about10% lower than that of natural aggregate.
In order to intensify the recycled aggregate and improve the properties of recycled concrete further, the strengthening effect and mechanism of sodium silicate modified by nano-SiC on the recycled aggregate concrete were studied. The results show that the strengthening effect is obvious,but it is influenced by concentration of sodium silicate and addition of nano-SiC. As the concentration of water glass is increased, the apparent density and bulk density of the recycled aggregate treated with water glass are firstly increased, the water absorption is gradually reduced, the water content is gradually increased, and the crushing index is increased firstly. With the increase of nano-SiC content, the apparent density and bulk density of recycled aggregate reinforced by nano-SiC solution increased firstly and then decreased, the water absorption and water content decreased first and then increased, and the crushing index decreased first and then increased. The properties of the recycled aggregate which intensified by modified sodium silicate solution with a concentration of 30% and addition of 0.75% nano-SiC are relatively good. The surface of recycled aggregate is even. Pores and cracks are filled with modified sodium silicate. The 28 d compressive strength of corresponding recycled concrete is about 45% higher than the recycled concrete when the recycled aggregate without any treatment, but it is about10% lower than that of natural aggregate.
引文
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[11]SINGH L P,BISHT V,ASWATHY M S,et al.Studies on performance enhancement of recycled aggregate by incorpo rating bio and nano materials[J].Construction and Building Materials,2018,181:217-226.
[2]丁小雅,张鹏,刘庆.水分与氯离子在再生混凝土中的迁移规律[J].混凝土与水泥制品,2018(9):32-35.
[3]B.González-Fonteboa,S.Seara-Paz,J.de Brito,et al.Recycled concrete with coarse recycled aggregate:An overview and analysis[J].Materials De Construccion,2018,68:1-29.
[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(12):96-103,126.
[5]GUO H,SHI C J,GUAN X M,et al.Durability of recycled aggregate concrete-A review[J].Cement&Concrete Composites,2018,89:251-259.
[6]应敬伟,蒙秋江,肖建庄.再生骨料CO2强化及其对混凝土抗压强度的影响[J].建筑材料学报,2017,20(2):277-282.
[7]YANG L X,QIAN Y L,FANG Q Q,et al.Effects of Recycled Coarse Aggregate Reinforcing Treated by Water-Glass on the Performance of Recycled Concrete[J].Proceedings of the3RD International Conference on Material Engineering and Application(ICMEA 2016),2016,103:181-186.
[8]程海丽,张迪.水玻璃强化再生骨料混凝土的抗冻性和抗侵蚀性探析[J].新型建筑材料,2008(8):5-7.
[9]张津践.再生混凝土纳米强化技术及微观结构分析[D].杭州:浙江大学,2012.
[10]闫洪生.纳米SiO2强化再生粗骨料混凝土力学性能的试验研究[D].青岛:青岛理工大学,2017.
[11]SINGH L P,BISHT V,ASWATHY M S,et al.Studies on performance enhancement of recycled aggregate by incorpo rating bio and nano materials[J].Construction and Building Materials,2018,181:217-226.