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第六期
刘俊华1,孙 勇1,刘凤利2,张承志2
摘 要:为实现建筑垃圾的再生利用和特细砂的大宗利用,将废混凝土再生粗砂、废砖再生粗砂分别与特细砂掺配,得到建筑垃圾再生混合砂,研究其对混凝土表观密度、和易性、抗压强度和劈裂抗拉强度的影响。试验结果表明,建筑垃圾再生混合砂替代天然砂配制混凝土,可达到设计和易性和强度要求,并有利于降低容重;废砖再生混合砂混凝土的韧性优于普通混凝土,而废混凝土再生混合砂混凝土的韧性劣于普通混凝土。
Abstract: In order to achieve the recycling of construction wastes and comprehensive utilization of super-fine sand, the construction wastes mixed sand is made by super-fine sand partly replaced by recycled concrete coarse sand or recycled brick coarse sand. The influences of construction wastes mixed sand on the apparent density, workability, compressive strength and tensile splitting strength of concrete are studied. Based on comparison tests, conclusions can be drawn that concrete using construction wastes mixed sand instead of natural sand can meet the standard of the workability and strength design while decreasing concrete unit weight. The toughness of recycled brick mixed sand concrete is better than that of common concrete. However, the toughness of recycled concrete mixed sand concrete is just on the contrary.
林 聪,刘福胜,任淑霞,赵井辉,高文涛
摘 要:研究了花岗岩石粉、粉煤灰、石屑石粉单掺(10%、20%、30%),以及双掺对混凝土收缩抗裂各项性能的影响。结果表明,花岗岩石粉、石屑石粉掺量20%、粉煤灰掺量30%为最优掺量,花岗岩石粉与粉煤灰、石屑石粉与粉煤灰均按1:2双掺最优。
Abstract: The influences of single doped 10% granite powder, 20% fly ash or 30% stone chip powder and double mixing 20% of the granite powder and fly ash or 20% of stone chip powder and fly ash on the shrinkage and crack properties of concrete are studied. The results show that the optimal content of the granite powder, stone chip powder and fly ash is 20%, 20% and 30% respectively; the co-doped optimal proportions of the granite powder and fly ash, stone chip powder and fly ash are the same, all 1:2.
庄志勇,赵若红,傅继阳,区浩文
摘 要:选择工业废弃料钢屑和铁砂作为屏蔽介质,掺入到水泥材料中制得水泥基复合屏蔽材料,研究其屏蔽效能和导电性能。结果表明,钢屑水泥基复合材料的导电性能和电磁屏蔽效能会随着钢屑含量的增加而显著增加,在0.3~3GHz频率范围内屏蔽效能最大达到35.65dB,电阻率仅为34.43,另外,水泥基复合材料的厚度对其电磁屏蔽效能影响较大,随着厚度增加其屏蔽效能显著增加。Abstract:Thecement-basedcompositeshieldingmaterialismadeofcementandshieldingmediums,whichareindustrialwastematerials-steelscrapandironsand.Theeffectsoftheseshieldingmediumsonshieldingpropertiesandelectricvolumeresistivityarestudied.Theresultsindicatethatwhenthecontentofsteelscrapincrease,theshieldingeffectivenessandconductivepropertiesofthesteelscrap-cementcompositesareimprovedgreatly.Theshieldingeffectivenessofcompositesisshownupto35.65dBin0.3-3GHzfrequencyrange,andtheresistivityoftheconductivecompositesisonly34.43.Inaddition,thethicknessofthecompositeshasanobviousinfluenceonitselectromagneticshieldingeffectiveness,whenthethicknessincrease,theshieldingeffectivenessisimprovedobviously.
范鹏飞,许家文,李 珠
摘 要:通过在再生混凝土中加入不同掺量的橡胶颗粒和纳米材料,分析了橡胶颗粒、纳米材料和龄期对再生混凝土的抗压强度影响。试验表明,抗压强度随着再生混凝土中橡胶颗粒的掺量的增加而降低,当再生混凝土中的橡胶颗粒掺量为3%时,混凝土的立方体抗压强度和轴心抗压强度降低量最不明显,分别降低7.73%和6.19%;掺入纳米材料可以较大幅度的提高再生混凝土的抗压强度,尤其可以提高再生混凝土的早期强度;再生混凝土的早期强度增长速度较大,而后期增长效果并不明显。
Abstract: Through adding different contents of rubber particles and nano-materials into the recycled concrete, the influences of rubber particles, nano-materials and ages on the compressive strength of recycled concrete are analyzed. The results show that the compressive strength of recycled concrete reduces with the increasing of rubber content, and when the rubber content is 3% in the recycled concrete, the cube compressive strength and axial compressive strength of concrete reduce by 7.73% and 6.19% respectively; Nano-materials can significantly increase the compressive strength of recycled concrete, especially for the early strength of recycled concrete, but it’s not obvious effect on the later strength growth of recycled concrete.
孟文清,李亚龙,张亚鹏
摘 要:应用ANSYS有限元软件,模拟文汇路地铁车站明挖深基坑支护中土体和支护结构的应变和位移,选择了合理的支护结构和土体的有限元设计参数,分析了基坑可能产生的变形与破坏形式。通过实际施工监测结果,验证了有限元模拟的设计参数的合理性,提出了设计与施工中应采取的应对措施。
Abstract: The deep foundation pit of the wenhui rod subway station was simulated by the element software of ANSYS to get the displacement and strain of the soil and supporting structure. The reasonable finite element design parameters of the supporting structure and the soil are chose, and the potential deformation and failure mode of the pit are analyzed. In addition, based on the actual construction monitoring results, the reasonableness of the design parameters of the finite element simulation is verified, and the response measures for the design and construction are put forward.
摘 要:通过现场试验,研究了锤击法沉桩对周边土孔隙水压力的影响。试验结果表明,锤击法沉桩会引起桩周粘土层孔隙水压力急剧上升,但在第二天就能基本消散掉。粉砂、粉土层由于有较好的排水特性,孔隙水压力的增长相对要小得多。
Abstract: Base on the field test, the influence of pile-sinking with hammering method on the pore water pressure in soils around is studied. The test results show that the pore water pressure can be increased rapidly due to pile-sinking with hammering method, but it can be scattered nearly on the second day. There is fewer increase of the pore water pressure in sand and silt layers as a result of the good drainage characteristics.