掺粉煤灰机场道面混凝土抗冻融试验研究

针对我国高寒地区机场道面混凝土抗冻融性能不良的现象,结合某机场工程,对掺粉煤灰机场道面混凝土进行冻融试验,探讨了水胶比、粉煤灰掺量、引气减水剂掺量对粉煤灰混凝土抗冻融耐久性的影响。结果表明,随着粉煤灰及引气减水剂掺量的增加,机场混凝土道面的抗冻融性能会相应地提高。可对高寒地区机场水泥混凝土道面设计、维护及剩余寿命预测等问题提供参考。     

高寒干燥地区大含气量碾压混凝土抗冻耐久性研究

西北高寒干燥地区的碾压混凝土工程,由于引气困难,导致其抗冻耐久性得不到保证。针对新疆玛纳斯县石门子水库工程,分别试验研究了含气量、粉煤灰掺量和水胶比对碾压混凝土抗冻耐久性能的影响,大含气量及粉煤灰掺量对碾压混凝土强度和抗渗性能的影响。结果表明,在不降低混凝土强度和抗渗要求的情况下,大掺量引气剂和降低水胶比能显著提高碾压混凝土在高寒干燥地区的抗冻耐久性。     

大掺量粉煤灰水泥混凝土性能研究

通过对大掺量粉煤灰水泥与普通硅酸盐水泥配制的混凝土性能进行对比研究,表明大掺量粉煤灰水泥混凝土性能类似于普通水泥混凝土,且具有更好的耐化学侵蚀能力。     

大掺量粉煤灰水泥混凝土性能研究

通过大掺量粉煤灰水泥与普通硅酸盐水泥配制的混凝土性能进行了对比研究表明,大掺量粉煤灰水泥混凝土性能类似于普通水泥混凝土,且具有更好的耐化学侵蚀能力。     

大掺量粉煤灰水泥混凝土性能研究

通过对大掺量粉煤灰水泥与普通硅酸盐水泥配制的混凝土性能进行对比研究，表明大掺量粉煤灰水泥混凝土性能类似于普通水泥混凝土，且具有更好的耐化学侵蚀能力。     

大体积混凝土抗裂性能研究

为了解决大体积混凝土开裂问题,采用一级粉煤灰,掺加高效缓凝保塑减水剂来配制混凝土,在改变粉煤灰掺量(0%,20%,30%,40%,50%)、水泥和粉煤灰总用量的条件下进行试验研究。通过混凝土绝热升温试验、掺粉煤灰水泥水化热试验和混凝土干缩性能试验,发现混凝土的抗裂性能随着粉煤灰掺量在一定范围内的上升而加强。如果将粉煤灰掺量控制在一定范围内,可以满足混凝土的抗裂性能,对大体积混凝土的应用提供了质量保证,防止了大体积混凝土的开裂产生。     

五岛水泥和小野田水泥的大掺量粉煤灰混凝土的抗压强度实验研究

对五岛水泥和小野田水泥的大掺量粉煤灰混凝土进行了抗压强度试验研究.通过对大产量粉煤灰混凝土同普通生产用的混凝土进行对比分析,得出结论:1)生产用混凝土的早期强度要好于大掺量粉煤灰混凝土的早期强度;2)小野田水泥大掺量粉煤灰混凝土早期强度要好于五岛水泥大掺量粉煤灰混凝土的早期强度;3)普通生产用混凝土28d之后的强度增长速度相对于大掺量粉煤灰混凝土的增长速度较慢.说明:粉煤灰对混凝土的后期强度增长起到了促进作用.     

掺粉煤灰和矿渣粉大流动度混凝土的碳化性能

研究了复掺Ⅱ级粉煤灰和同等细度矿渣粉且同时加入高交减水剂的大流动度（约180mm)混凝土的抗碳化性能。试验中改变了取代水泥量（最大为80％）及掺合料中粉煤灰和矿渣粉的比例等条件,混凝土碳化深度随时间的变化可用幂函数d=at^b表示,其中b值大多位于0．3－0．4,复掺可使取代水泥量提高,对设计寿命为50年的混凝土,在其他性能满足工程要求的条件下,仅就碳化性能而言,可掺加40％的粉煤灰,若采用粉煤灰与矿渣粉复掺,则在掺合料掺量分别为60％,70％及80％时,相应地可掺加40％,30％及15％的粉煤灰。     

大掺量粉煤灰混凝土的性能特征

1 序 日本早在50年代就已将粉煤灰用于混凝土,即使是水库用的混凝土,粉煤灰掺量也用到了水泥量的30％,但该掺量还是低于高炉矿渣粉末掺量。 本次研究着重对大掺量粉煤灰混凝土的单位水泥用量不同,而粉煤灰掺量又较大,具体为:水泥量的1.1、1.3、1.5及1.7倍时的混凝土配合比、强度、弹性模量、干燥     

掺粉煤灰混凝土抗盐冻剥蚀性能研究

试验结果表明 :粉煤灰掺量为 2 0 %的混凝土在适量引气的条件下具有良好的抗盐冻性能 ;粉煤灰掺量为 5 5 %的混凝土在掺加UEA膨胀剂后其抗盐冻性能有明显改善 ;大掺量粉煤灰硫铝酸盐水泥混凝土的抗盐冻性大大低于同掺量的硅酸盐水泥混凝土     

粉煤灰混凝土抗冻性能试验研究

对粉煤灰取代水泥量分别为0,30%,40%,50%,60%的混凝土,进行冻融试验。试验结果表明:粉煤灰取代水泥30%时,其抗冻性能与基准混凝土相当;粉煤灰取代水泥超过30%时,其抗冻性能较基准混凝土差,劣化程度随粉煤灰取代水泥量的增加而增加。     

粉煤灰双掺混凝土冻融循环试验研究

随着我国电力事业的发展,粉煤灰的排放量也在逐年增加,以至造成了严重的环境污染。粉煤灰和减水剂双掺混凝土,不仅能大量利用粉煤灰,节约水泥,而且能提高工程质量和降低成本。本文以C30为例,分析了粉煤灰双掺混凝土和普通混凝土耐久性指数,论证了粉煤灰双掺混凝土工程应用的可行性。     

颗粒细度与粉煤灰水泥胶砂性能的关系

将原状粉煤灰进行粉磨,然后用勃氏法测其比表面积,用SEM分析其颗粒形貌.采用灰色关联分析方法研究了粉煤灰和水泥颗粒细度与粉煤灰水泥胶砂性能的关系.研究表明:选择具有优异颗粒形貌的粉煤灰和水泥是配制高性能粉煤灰混凝土的首要步骤;通过适当提高粉煤灰颗粒细度,适当降低水泥颗粒细度,可以使粉煤灰混凝土获得较高的抗压和抗折强度;通过适当提高粉煤灰颗粒细度,可以减少混凝土拌和用水量,提高混凝土流动性.     

Properties of steel fiber reinforced fly ash concrete

This paper reports on a comprehensive study on the properties of concrete containing fly ash and steel fibers. Properties studied include unit weight and workability of fresh concrete, and compressive strength, flexural tensile strength, splitting tensile strength, elasticity modulus, sorptivity coefficient, drying shrinkage and freeze–thaw resistance of hardened concrete. Fly ash content used was 0%, 15% and 30% in mass basis, and fiber volume fraction was 0%, 0.25%, 0.5%, 1.0% and 1.5% in volume basis. The laboratory results showed that steel fiber addition, either into Portland cement concrete or fly ash concrete, improve the tensile strength properties, drying shrinkage and freeze–thaw resistance. However, it reduced workability and increase sorptivity coefficient. Although fly ash replacement reduce strength properties, it improves workability, reduces drying shrinkage and increases freeze–thaw resistance of steel fiber reinforced concrete. The performed experiments show that the behaviour of fly ash concrete is similar to that of Portland cement concrete when fly ash is added.     

粉煤灰与钢纤维复合高性能道面混凝土试验研究

采用粉煤灰和钢纤维复合的技术路线,研究了粉煤灰等量取代、超量取代、水泥量不变的条件下对钢纤维混凝土性能的影响.结果表明,粉煤灰和钢纤维的掺入可提高道面混凝土的力学性能,改善混凝土的内部结构,并可降低道面混凝土的投资.     

混凝土收缩性能的若干问题研究

研究了水灰比、水泥用量、含气量、粉煤灰掺量、矿渣粉掺量对混凝土收缩性能的影响,结果表明:当水灰比为0.40～0.45时,单位立方米水泥用量大于400 kg时,含气量大于7.0%时,混凝土收缩量较大;混凝土收缩量随粉煤灰掺量的增加而减小,当粉煤灰掺量为30%时,收缩量最小;混凝土收缩量随矿渣粉掺量的增加而增大,但矿渣粉的掺量对混凝土收缩的影响较小。     

原状粉煤灰与钢纤维复合用于机场道面混凝土

将原状粉煤灰掺入机场道面用钢纤维混凝土中,研究了以原状粉煤灰等量取代、超量取代水泥及在水泥用量不变的条件下仅将其作为微细集料使用时对钢纤维混凝土性能的影响,探讨原状粉煤灰在机场道面用钢纤维混凝土中应用的可能性,以提高机场道面用钢纤维混凝土的力学性能,改善其内部结构,并降低一次性投资,为推广应用该项技术提供依据.     

Properties of sustainable concrete containing fly ash,slag and recycled concrete aggregate

The suitability of using more “sustainable” concrete for wind turbine foundations and other applications involving large quantities of concrete was investigated. The approach taken was to make material substitutions so that the environmental, energy and CO₂-impact of concrete could be reduced. This was accomplished by partial replacement of cement with large volumes of fly ash or blast furnace slag and by using recycled concrete aggregate.Five basic concrete mixes were considered. These were: (1) conventional mix with no material substitutions, (2) 50% replacement of cement with fly ash, (3) 50% replacement of cement with blast furnace slag, (4) 70% replacement of cement with blast furnace slag and (5) 25% replacement of cement with fly ash and 25% replacement with blast furnace slag. Recycled concrete aggregate was investigated in conventional and slag-modified concretes. Properties investigated included compressive and tensile strengths, elastic modulus, coefficient of permeability and durability in chloride and sulphate solutions. It was determined that the mixes containing 50% slag gave the best overall performance. Slag was particularly beneficial for concrete with recycled aggregate and could reduce strength losses. Durability tests indicated slight increases in coefficient of permeability and chloride diffusion coefficient when using recycled concrete aggregate. However, values remained acceptable for durable concrete and the chloride diffusion coefficient was improved by incorporation of slag in the mix. Concrete with 50% fly ash had relatively poor performance for the materials and mix proportions used in this study and it is recommended that such mixes be thoroughly tested before use in construction projects.     

超细粉煤灰配制碎砖骨料混凝土试验研究

采用粉煤灰超量取代法配制再生混凝土,利用正交试验法分析了影响再生混凝土强度的主要因素。并选择了配制粉煤灰再生混凝土的较佳配合比。试验结果表明:在再生骨料掺量、粉煤灰取代水泥量、超代系数和水灰比4个因素中,对再生混凝土不同龄期抗压强度的影响顺序是不一样的,但是最主要的影响因素都是水灰比。经正交试验确定的较优配合比设计的混凝土和易性和强度均能满足一般工程的质量要求。     

Utilization of treated spent liquor sludge with fly ash in cement and concrete

Design mix of M-20 concrete was prepared in the laboratory by substituting cement with the treated spent liquor sludge (TSLS) and fly ash. During the study, TSLS is fixed at 7.5% by weight, and fly ash is varied as 5%, 10%, 15%, 20% and 25% to study the possibility of replacement of cement. A 15% fly ash gives the optimum compressive strength. Addition of fly ash has resulted in complete removal of toxicity as per US EPA toxicity characteristic leaching procedure (TCLP) test. A total of 7.5% sludge and 15% fly ash in M-20 concrete is expected to save Rs. 252/m³ (≈USD 5.3/m³⁾ of concrete.