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第八期
摘 要:对不同掺量橡胶再生混凝土的轴压强度和弹性模量进行了测定,并对比了普通混凝土与普通再生混凝土的轴压强度与弹性模量,分析了橡胶粉对再生混凝土轴压强度和弹性模量的影响,使用扫描电镜对混凝土的微观结构进行研究。结果表明,橡胶粉会降低再生混凝土的轴压强度和弹性模量,增大孔隙率并改变孔隙结构。当橡胶粉掺量控制在5%时,橡胶再生混凝土可以满足使用强度要求,且有较好的延性;当橡胶粉掺量超过7%时,由于强度损失过大,橡胶再生混凝土不适合工程应用。
Abstract: The axial compressive strength and elastic modulus of recycled concrete with different dosage of rubber powder were measured, the axial compressive strength and elastic modulus of ordinary concrete and ordinary concrete with recycled concrete were contrasted, effects of rubber powder on axial compressive strength and elastic modulus of recycled concrete were analyzed, micro structure of concrete was studied by SEM. The results showed that, rubber powder would decrease axial compressive strength and elastic modulus of recycled concrete, that would enhance porosity and change its pore structure at the same time. When dosage of rubber powder is controlled at 5%, rubber recycled concrete could meet strength requirements and had good ductility; when dosage exceeded 7%, rubber recycled concrete was not suitable for engineering applications as large loss of strength.
余 阳,夏冬桃,吴伟波,熊思慧,魏贵添
摘 要:为提高普通混凝土路面的早期强度、抗弯性能,缩短养护时间,运用正交试验方法对9组钢纤维橡胶路面混凝土和一组普通混凝土试件分别进行了龄期3d和28d抗压强度和抗折强度试验,通过直观分析和方差分析,考察各因素对路面混凝土抗压和抗折强度的影响。结果表明,修补剂、钢纤维、40目橡胶粉在低掺量下,钢纤维橡胶路面混凝土的最佳配比为修补剂掺量15%,钢纤维体积率0.5%,橡胶粉掺量5.0%。修补剂对钢纤维橡胶路面混凝土的抗压和抗折强度影响最大,最高可提高强度的68.6%;钢纤维对抗折强度的影响程度高于橡胶粉;钢纤维和橡胶粉对抗压强度无明显影响,加入适量的钢纤维和橡胶粉可提高混凝土的抗折强度及弯曲韧性。
Abstract: In order to improve the early strength and flexural performance of ordinary concrete pavement, and shorten curing time, compressive strength and flexural strength experiment for 3d and 28d of 9 groups of steel fiber reinforced rubber pavement concrete specimens and a set of common concrete specimen were carried out by orthogonal experiment method. Through the intuitive analysis and variance analysis, the influence of various factors on compressive and flexural strength of pavement concrete were investigated. The results showed that, at low dosages of repairing adhesive, steel fiber and 40 mesh rubber powder, the best proportion of steel fiber reinforced rubber pavement concrete for repairing adhesive content was 15%, steel fiber volume rate was 0.5%, and rubber powder content was 5.0%. The largest effects on compressive strength and flexural strength of steel fiber reinforced pavement concrete is repairing adhesive, the largest strength can be increased by 68.6%. The influence degree of steel fiber on flexural strength is higher than rubber powder, steel fiber and rubber powder had no significant effect for compressive strength, and adding suitable amount of fiber and rubber powder can improve flexural strength and flexural toughness of concrete.
崔孝炜,狄燕清,南 宁,刘 璇,王景行
摘 要:通过极差分析和功效系数分析研究了钼尾矿与水泥的质量比、 PC减水剂用量及水灰比对钼尾矿骨料混凝土抗折强度以及抗压强度的影响。结果表明:当钼尾矿与水泥的质量比为4:6,PC减水剂掺入量为水泥量的0.5%,水灰比为0.25时,可制得28d抗折强度达到11.25MPa、抗压强度达到45.5MPa的钼尾矿混凝土,符合国家标准抗压强度MU30等级的要求。
Abstract: Through range analysis and efficiency coefficient, the influences of molybdenum tailings and cement mass ratio, PC superplasticizer dosage and water-cement ratio on flexural strength and compressive strength of molybdenum tailings concrete were studied. The results showed that, when mass ratio of molybdenum tailings and cement is 4:6, dosage of PC superplasticizer is 0.5% amount of cement, water-cement ratio is 0.25, the flexural strength can be obtained 11.25MPa in 28d, compressive strength of molybdenum tailings concrete is 45.5MPa, which meets MU30 level for compressive strength of national standard.
摘 要:根据启东本地建筑市场的现有状况,从原材料的选择入手,通过试验和对比,最终确定了C45高性能混凝土在实际工程中的配合比,并给出了中高强高性能混凝土泵送施工工艺方案。
Abstract: According to construction market in Qidong, from choosing raw materials, mix proportion of C45 high performance concrete in pratical project is finally determined through experiment and comparison, the scheme ordinary to high-strength and high performance concrete pumping construction technology is carried out.
钱远顺1,孙仁娟1,刘传波2,李长旭3,管延华1
摘 要:现有碳纤维布(CFRP)预应力张拉设备结构复杂,施工繁琐,不能够满足现场施工要求。试验研究发现,仅粘贴一层碳纤维布对被加固构件的性能提升很小,不能满足加固要求。通过试验研究,研发了一种可以对双层碳纤维布同时张拉的加固方法和施工工艺,并采用预紧螺栓锚固钢板对碳纤维布锚固,对9根试验梁进行了试验。结果表明,该张拉设备操作方便,施工快捷,可大大提高施工效率,通过锚固措施,可有效防止碳纤维布在加载过程中发生滑移和大面积剥离现象。
Abstract: The existing CFRP pre-stressed streching equipment with complex structure, construction tedious, can not satisfy site construction requirements. Experimental research found that, only a piece of carbon fiber can’t enhance performance of the strengthened beam, which can not meet requirements of reinforcement. Through experimental research, a double CFRP can be tensioned reinforcement methods and construction technology at the same time, which is used by preloaded bolt anchorage steel to anchorage the CFRP, and experiment of 9 test beams is studied. The results show that, the tensioning device is easy to operate, quick construction, and can greatly improve efficiency of construction, which can effectively prevent the CFRP in process of loading slip and large area of stripping phenomenon by anchoring measures.
韩彦军,张 良,张 宇,王艳莉
摘 要:针对现有混凝土振捣设备不能较好地满足PC 构件的柔性化生产需求问题,设计了一种多功能、满足中低频振动的混凝土振动台。对振动台的中频和低频部分进行了结构设计,为确定振动台低频部分的主要尺寸和运动规律,对并联机构进行了运动学求解,得到了驱动杆输入和动平台的位置、速度和加速度的关系,最后对振动台并联机构的布局进行了分析。该振动台采用振动电机和并联机构两种振动方式实现了中低频振捣,具有工作频率范围大、承载能力强的特点,有效提高了混凝土的振捣质量与效率。
Abstract:Because the existing concrete vibration equipment cannot better meet the need of the PC component flexible production, a new multi-function concrete vibrostand is designed. The structure of the vibrostand in the middle and low frequency is designed and analyzed. In order to determine the main size and movement of the low-frequency part of the shaking table, kinematics solution of parallel mechanism is discussed, and the position relation and the movement relation between the moving platform and the driving rod are obtained, and the layout of the vibrostand is also analyzed. Two vibration modes of the vibration motor and parallel mechanism are combined to realize the low and middle frequency vibration. The vibrostand has many advantages, such as large operating frequency range, heavy-load capability, and improve the quality and efficiency of the vibration of the concrete.