C100高强度自流平混凝土研究

研究了内掺硅粉对自流平混凝土强度和流动性的影响;根据试验数据总结出高强度自流平混凝土的强度经验公式;分析了掺硅粉的高强度自流平混凝土后期强度增长规律;采用42.5普通硅酸盐水泥、中砂、5~25mm碎石,水胶比不大于0.275,内掺硅粉不少于4%,掺加适量的聚羧酸复合缓凝高效减水剂,可配制出C100高强度自流平混凝土。     

内掺钢渣、硅粉的C80高性能混凝土研究

研究了钢渣、硅粉掺量对混凝土强度与流动性的影响以及钢渣、硅粉混凝土强度规律。采用4 2 5普通硅酸盐水泥、中砂、5～ 2 5mm碎石、掺加适量NF 2 6缓凝高效减水剂 ,水胶比 0 2 6 ,钢渣、硅粉掺量均为 10 %或水胶比 0 2 4～ 0 31,钢渣掺量 10 %～ 30 % ,硅粉掺量 15 % ,可配制C80高性能混凝土 ,并给出了混凝土配合比参考公式。     

C110高强度大流动性混凝土研究

研究了内掺硅粉对混凝土强度和流动性的影响;根据试验数据总结出内掺硅粉混凝土的28d抗压强度规律;研究了混凝土后期强度的增长规律;采用P.O.42.5普通硅酸盐水泥、中砂、5~25mm碎石,内掺7%硅粉,水胶比0.219,掺加适量的聚羧酸复合缓凝高效减水剂,可配制出C110高强度大流动性混凝土。     

掺粉煤灰和硅粉的C90高强度自流平混凝土研究

研究了内掺粉煤灰和硅粉对自流平混凝土强度和流动性的影响 ;根据试验数据总结出高强度自流平混凝土的强度经验公式 ;分析了掺粉煤灰和硅粉的高强度自流平混凝土后期强度增长规律 ;采用 4 2 5普通硅酸盐水泥、中砂、5～ 2 5mm碎石 ,水胶比 0 2 6 7～ 0 2 85 ,内掺 10 %粉煤灰和 10 %～ 15 %硅粉 ,或水胶比0 2 6 6 ,内掺 2 0 %粉煤灰和 15 %硅粉 ,掺加适量的NF 2 6缓凝高效减水剂 ,能配制出C90高强度自流平混凝土。     

硅粉混凝土的施工工艺

掺硅粉混凝土与常规混凝土相比具有强度高和耐久性好的特点。在现场可将这种高活性的火山灰质材料制出每平方时14000磅强度的混凝土。同时,由于极细的硅粉微粒的反应产物填塞了混凝土的内部气孔,故减少了对钢筋的腐蚀,这样减慢了碳化作用并使氯化物阻于混凝土之外。由于这些优点,现在有许多工程师指定将硅粉混凝土用于高强度结构、抗腐蚀表面层及掺防冻剂和盐水的暴露结构。掺加硅粉不能代替混凝土的良好操作实     

内掺锂渣和硅粉的100MPa高强度大流动性混凝土研究

研究了内掺锂渣和硅粉对混凝土强度和流动性的影响 ;根据试验数据总结出内掺锂渣和硅粉混凝土的 2 8d抗压强度规律 ,研究了混凝土后期强度的增长规律 ;采用 4 2 5普通硅酸盐水泥、中砂、5～ 2 5mm碎石 ,内掺 10 %～ 15 %锂渣和 5 %硅粉 ,水胶比 0 2 5 5～ 0 2 6 8,或内掺 0～ 15 %锂渣和 10 %硅粉 ,水胶比 0 2 6 0～0 30 5 ,掺加适量的NF - 2 - 6缓凝高效减水剂 ,可配制出 10 0MPa高强度大流动性混凝土。     

谈硅粉在混凝土中的各项性能

通过混凝土的抗压强度、劈裂强度、抗折强度以及收缩四项基本性能进行了不同掺量的硅粉在其混凝土中发生的各种性能影响,再结合所查阅的文献资料,对比得出硅粉混凝土的基本特性。     

内掺硅粉的C80高强度大流动性混凝土研究

分析了高强度大流动性混凝土的配制特点 ,研究了硅粉掺量对混凝土强度和流动性的影响 ,根据试验数据总结出内掺硅粉的高强度大流动性混凝土的强度经验公式 ,分析了内掺硅粉对混凝土2 8d及后期强度的增强机理。     

掺硅粉混凝土路用性能研究

分析了硅粉对混凝土作用机理，研究了掺硅粉路面混凝土的路用性能和施工工艺及技术经济性。结果表明，从抗折强度和经济性指标考虑，路面混凝土存在最佳硅粉掺量问题；与不掺硅粉路面混凝土相比，路面混凝土中按最佳掺量15～20kg／m^3掺入硅粉，能显著提高路面混凝土的路用性能和降低工程造价，如抗折强度提高10％、极限拉应变提高22％以上、压折比降低7％、耐磨性提高42％和抗冻性能提高近十倍、材料费用可节约11％左右，表明掺硅粉混凝土在路面工程中应用是可行的。     

硅粉、粉煤灰作掺合料的C80高性能混凝土研究

研究了硅粉、粉煤灰掺量对混凝土强度与流动性的影响和硅粉、粉煤灰混凝土28d强度规律及混凝土的后期强度增长规律。采用P.O.42.5级普通硅酸盐水泥、中砂、5~25mm碎石及适量NF2-6缓凝高效减水剂,水胶比0.28,硅粉掺量5%,粉煤灰掺量5%~15%或硅粉掺量10%~15%,粉煤灰掺量5%~20%及水胶比0.31,硅粉掺量15%,粉煤灰掺量5%~10%时,可配制出C80高性能混凝土并且给出混凝土配合比参考公式。     

硅粉对纤维橡胶再生混凝土抗压性能影响试验

以普通混凝土和橡胶再生混凝土为研究对象,通过掺入硅粉和纤维材料研究强化环保型混凝土抗压性能的方法。用再生混凝土100%等体积代替粗骨料,用橡胶颗粒20%等体积代替细骨料,内掺10%（质量分数）或外掺3%（质量分数）硅粉以及掺入聚丙烯纤维或钢纤维,制备了4组12个混凝土立方体试件,通过轴压试验研究了混凝土试件的破坏模式、抗压强度和工作性能。结果表明:与单一掺入硅粉相比,硅粉和聚丙烯纤维的复合掺入能进一步强化混凝土的抗压性能;硅粉的掺入可以强化浆体与橡胶颗粒间的界面性能,提高钢纤维橡胶再生混凝土的抗压强度;硅粉和纤维材料对混凝土的工作性能有负作用,其复合掺入时建议采用适量的减水剂。     

掺稻壳灰/硅灰混凝土的性能研究

研究了稻壳灰、硅灰、稻壳灰+粉煤灰、硅灰+粉煤灰对混凝土抗压强度、抗折强度、抗硫酸侵蚀能力和抗碳化能力的影响.结果表明:掺加5％～10％稻壳灰或硅灰有助于提升混凝土的抗压强度和抗折强度,且稻壳灰、硅灰掺量越高抗压强度越高,掺硅灰混凝土相对于掺稻壳灰混凝土的抗压和抗折强度更高,掺稻壳灰+粉煤灰、硅灰+粉煤灰试件的抗压和抗...     

Properties of polypropylene fiber reinforced silica fume expansive-cement concrete

This paper reports on a comprehensive study on the mechanical properties of expansive-cement concrete containing silica fume and polypropylene fibers. Properties studied include those of the fresh mix properties, length change, rapid chloride permeability, compressive strength, flexural behavior, and bond of hardened concrete. Silica fume content used was 5 and 10% and fiber volume fraction was 0.10, 0.30, and 0.50%. Results show that the use of 5% silica fume combined with 0.30% fiber volume fraction results in optimum mixture design for repair applications from the standpoints of workability, bond, strength, length change and permeability.     

The effects of silica fume and polypropylene fibers on the impact resistance and mechanical properties of concrete

Impact resistance and strength performance of concrete mixtures with 0.36 and 0.46 water–cement ratios made with polypropylene and silica fume are examined. Polypropylene fiber with 12-mm length and four volume fractions of 0%, 0.2%, 0.3% and 0.5% are used. In pre-determined mixtures, silica fume is used as cement replacement material at 8% weight of cement. The results show that incorporating polypropylene fibers improves mechanical properties. The addition of silica fume facilitates the dispersion of fibers and improves the strength properties, particularly the impact resistance of concretes. It is shown that using 0.5% polypropylene fiber in the silica fume mixture increases compressive split tensile, and flexural strength, and especially the performance of concrete under impact loading.     

Influence of dry and wet curing conditions on compressive strength of silica fume concrete

This paper reports a part of an ongoing laboratory investigation in which the compressive strength of silica fume concrete is studied under dry and wet curing conditions. In the study, a total of 48 concretes, including control Portland cement concrete and silica fume concrete, were produced with four different water–cement ratios (0.3, 0.4, 0.5, 0.6), three different cement dosages (350, 400, 450 kg/m³) and three partial silica fume replacement ratios (10%, 15%, 20%). A hyperplastisizer was used in concrete at various quantities to provide and keep a constant workability. Three cubic samples produced from fresh concrete were demoulded after a day; then, they were cured at 20±2 °C with 65% relative humidity (RH), and three other cubic samples were cured at 20±2 °C with 100% RH until the samples were used for compressive strength measurement at 28 days. The comparison was made on the basis of compressive strength between silica fume concrete and control Portland cement concrete. Silica fume concretes were also compared among themselves. The comparisons showed that compressive strength of silica fume concrete cured at 65% RH was influenced more than that of Portland cement concrete. It was found that the compressive strength of silica fume concrete cured at 65% RH was, at average, 13% lower than that of silica fume concrete cured at 100% RH. The increase in the water–cementitious material ratios makes the concrete more sensitive to dry curing conditions. The influence of dry curing conditions on silica fume concrete was marked as the replacement ratio of silica fume increased.     

矿物掺合料对植生混凝土抗压强度及pH值的影响研究

采用矿物掺合料等量取代水泥的方法配制植生混凝土,研究了粉煤灰、硅灰及偏高岭土对混凝土抗压强度和内部孔隙pH值发展的影响规律。研究结果表明:单掺粉煤灰、硅灰及偏高岭土植生混凝土,28 d抗压强度达8.0~10.0 MPa,孔隙率为30%以上,90 d孔溶液pH值降低至11.6~11.8。满足河流护岸、道路护坡等对植生混凝土要求。     

关于硅灰和高性能混凝土的一些思考

硅灰的商业化应用在美国已有25年的历史。在此期间,硅灰从一种处于研究阶段的材料演变成一种在混凝土中被广泛规定使用的组分。硅粉在被市场所接纳的时间,恰好是“高性能混凝土”一词产生的前夕,有充分的理由说明：最初的硅灰混凝土项目正是高性能混凝土的起源。本文简述了在美国市场中硅灰使用的发展历史;回顾了硅灰混凝土如何发展成为高性能混凝土;并总结了使用硅灰的适用场合、配合比、抹面和施工性能等方面的经验。     

Assessing the effectiveness of pozzolans in massive high-strength concrete

This paper investigates the effects of supplementary cementitious materials on the temperature rising profile, heat evolution and early-age strength development of medium- and high-strength concrete. A total of 13 different mixtures were prepared, with two water–cement ratios (0.3 and 0.46). Natural pozzolan, fly ash, and silica fume were included in the specimens. The results showed that natural pozzolan, particularly fly ash served to decrease the amplitude of peak temperature, delay the occurrence of the peak, and decrease the sharpness of the temperature rising profiles. In contrast, the temperature profile of silica fume specimens was similar to those without silica fume. It was found that the best mixture, the highest early-age strength and the lowest heat liberation, corresponded to the specimen containing fly ash at 15% (be cement weight). This result justifies the advantage effect of fly ash which is able to develop sufficient tensile strength to resist thermal cracking potential in massive high-strength concrete.