硅灰用于自密实高性能道面混凝土的性能研究

为研究硅灰用于自密实高性能道面混凝土的效果,通过对比试验方法研究了掺入硅灰以后混凝土工作性能、力学性能和抗冻性能的变化,证明了加入硅灰可以显著提高混凝土的综合性能,可以用于自密实高性能路面混凝土的工程实践。     

硅灰对自密实混凝土性能的影响

自密实混凝土仅依靠自重就能够流动,在浇筑时不需要振捣,并能保持良好的匀质性,具有良好的工作性、力学性能与耐久性.针对自密实混凝土的特点和施工要求,通过试验研究与分析,详细论述了硅灰对自密实混凝土流变性、强度、耐久性、稳定性及触变性等性能的影响,并对其改善的机理进行了分析.     

冻融和碳化共同作用下硅灰自密实混凝土耐久性试验研究

为了研究冻融和碳化共同作用下硅灰自密实混凝土的耐久性,对不同强度等级的自密实混凝土和普通混凝土分别进行冻融试验、碳化试验和冻融碳化复合试验。试验结果表明:硅灰自密实混凝土的抗冻性能高于相同强度等级的普通混凝土,虽然前者的抗碳化性能略低于后者,但经过冻融作用后前者表现出更好的抗碳化性能;强度等级越高,硅灰自密实混凝土的抗冻性能和抗碳化性能越好。     

钢纤维与聚丙烯纤维复合机场道面混凝土性能研究

采用粉煤灰、硅灰及钢纤维、聚丙烯纤维配制机制砂机场道面混凝土,通过单掺及复掺的方式,研究了不同掺量、不同配合比对机场道面混凝土力学性能、耐磨性能、抗冲击性能、抗冻性能的影响。结果表明,采用硅灰、粉煤灰与钢纤维、聚丙烯纤维复合的方式,在钢纤维、聚丙烯掺量分别为7.9kg/m~3和1.5kg/m~3的情况下,可配制出超高力学性能及优异耐久性能的道面混凝土。     

石灰石粉在自密实混凝土中应用的研究

研究了石灰石粉取代粉煤灰和矿渣粉对自密实混凝土的工作性能、力学性能和耐久性能的影响。结果表明:石灰石粉可以作为自密实混凝土的掺和料来使用,掺入石灰石粉后自密实混凝土有较好的工作性和耐久性,相比粉煤灰和矿渣粉,石灰石粉对混凝土力学性能的改善作用较小。     

硅灰配制海工自密实高性能混凝土的研究

开展了复掺硅灰与矿渣粉海工自密实高性能混凝土的试验研究.试验结果表明,矿渣粉较大的海工自密实混凝土工作性较差,采用硅灰替代矿渣粉可改善海工自密实混凝土的工作性,在复掺硅灰和矿渣粉总掺量为70％,硅灰掺量5％的条件下,掺入55％～65％矿渣粉自密实混凝土具有较高的流动性、填充性、间隙通过性和抗离析性等工作性;28 d抗压强度大于50 MPa,56d的电通量小于1 000C,90d扩散系数小于1.5×10-12 m2/s,具有较高的抗压强度和抗氯盐侵蚀性能,满足海洋环境下抗氯盐侵蚀的质量要求.     

海底隧道C40P10喷射混凝土的试验研究

针对某海底隧道工程对C40P10喷射混凝土的使用要求,实验研究了速凝剂、硅灰以及钢纤维对喷射混凝土工作性、力学性能以及耐久性的影响.结果表明,所配制的喷射混凝土的工作性良好,可满足现场湿喷工艺的要求;在喷射混凝土中加入硅灰和钢纤维能够显著改善其力学性能,增强其抗水渗透能力;掺入硅灰的喷射混凝土表现出优异的抗氯离子渗透能力,适合于海底隧道工程应用.     

C70自密实混凝土耐久性试验研究

研究了C70自密实混凝土的工作性、力学性能及耐久性能,对抗渗、抗冻、氯离子扩散系数进行了试验研究。结果表明,本研究所配制的C70自密实混凝土符合自密实混凝土的工作性要求,力学性能满足设计要求,抗渗等级大于P12,抗冻性能良好,28 d龄期的氯离子扩散系数为1.30×10~(-8) cm~2·s~(-1)。     

硅灰在超高强混凝土中的应用

研究了硅灰及其掺量对超高强混凝土物理性能、力学性能、耐久性方面的影响。结果表明:硅灰是一种高效的活性掺合料,在混凝土中掺入一定量的硅灰,能够显著提高混凝土的强度、抗渗性,抗冻性和耐久性,是配制超高强混凝土不可缺少的组分。     

粉煤灰在自密实混凝土中的应用探讨

探讨了粉煤灰应用到自密实混凝土中对其工作性、强度和耐久性的影响,试验研究了粉煤灰与高效减水剂的相容性,以及复掺粉煤灰和硅灰配制自密实混凝土。     

拉会大桥高性能硅粉混凝土试验研究

对拉会大桥预应力混凝土连续刚构桥采用的C50高性能硅粉混凝土进行了试验研究,主要研究硅粉掺量对C50高性能混凝土的工作和易性、抗氯离子渗透和抗碳化的影响。试验结果表明:掺入适量硅粉有助于提高高性能混凝土和易性,同时对改善混凝土抗氯离子渗透和抗碳化等耐久性有显著作用。根据试验确定拉会大桥C50高性能混凝土硅粉掺量为5.66%,据此制备的混凝土各方面性能较优,能满足规范和设计要求。     

免振高性能混凝土力学性能及耐久性研究

采用超细磨粉煤灰和复合高效减水剂双掺技术研制出了Ｃ６０～Ｃ８０免振高性能混凝土,在优选了免振高性能混凝土配合比主要设计参数的基础上,对免振与振捣成型的高性能混凝土的抗压强度、劈裂抗拉强度、抗折强度、弹性模量、抗冻性能、干综性能等进行了对比试验研究。结果表明：免振高性能混缔造人有优异的物理力学性能及耐久性。     

Assessing the effects of supplementary cementitious materials on the performance of low-cement roller compacted concrete pavement

Roller compacted concrete pavements (RCCP) are widely used for a variety of industrial and heavy-duty pavement applications that involve low speed traffic. The aim of this investigation is to evaluate the effects of using supplementary cementitious materials – silica fume and pumice – on the workability, compressive strength, and frost resistance of non-air-entrained low-cement content RCCP mixtures.Eight different RCCP mixtures were produced with four types of binder and two binder contents. A series of consistency, compressive strength, and long-term freeze–thaw tests were conducted. Test results indicate that the frost resistance of the low-cement RCCP mixtures improves with higher cementitious materials content. The addition of 10% silica fume increased both the compressive strength and frost resistance of the RCC mixtures; however, it significantly decreased the workability of fresh mixtures. The pumice made the specimens more workable, but had a negative impact on both the compressive strength and frost resistance.     

高性能引气路面混凝土研究

针对我国寒冷地区路面混凝土的耐久性不良现象,通过研究含气量对路面混凝土工作性、抗折强度、抗冻性能及耐磨性能的影响规律,采用引气刺和减水剂复配的技术途径,配制出了维勃稠度1 5～30 s、28 d抗折强度5.8MPa以上、抗冻性及耐磨性等耐久性优良的高性能路面混凝土,并提出了寒冷地区路面混凝土最大水灰比为0.45、最小水泥用昔为280 kg/m3、含气量范围为3%～5%.     

The effect of silica fume and high-volume Class C fly ash on mechanical properties,chloride penetration and freeze–thaw resistance of self-compacting concrete

In this study, cement has been replaced with a Class C fly ash (FA) in various proportions from 30% to 60%. Durability properties of various self-compacting concrete (SCC) mixtures such as, freezing and thawing, and chloride penetration resistance have been investigated besides mechanical properties within the scope of this study. Similar tests were carried out with the incorporation of 10% silica fume (SF) to the same mixtures. Test results indicate that SCC could be obtained with a high-volume FA. Ten percent SF additions to the system positively affected both the fresh and hardened properties of high-performance high-volume FA SCC. Although there is a little cement content, these mixtures have good mechanical properties, freeze–thaw and chloride penetration resistance.     

粘性材料对自密实混凝土性能的影响

自密实混凝土是高性能混凝土发展的一个重要分支和方向。本文通过向自密实混凝土配料中添加石粉、硅灰、偏高岭土这三种粘性材料来研究其对自密实混凝土拌合物性能以及成型后的力学性能和收缩的影响。     

Strength properties and durability aspects of high strength concrete using Korean metakaolin

Metakaolin is a cementitious material used as admixture to produce high strength concrete. In Korea, the utilization of this material remained mainly limited to fireproof walls but began recently to find applications as a replacement for silica fume in the manufacture of high performance concrete.In order to evaluate and compare the mechanical properties and durability of concrete using metakaolin, the following tests were conducted on concrete specimens using various replacements of silica fume and metakaolin; mechanical tests such as compressive, tensile and flexural strength tests, durability tests like rapid chloride permeability test, immersion test in acid solution, repeated freezing and thawing test and accelerated carbonation test.Strength tests revealed that the most appropriate strength was obtained for a substitution rate of metakaolin to binder ranging between 10% and 15%. It was observed that the resistance to chloride ion penetration reduced significantly as the proportion of silica fume and metakaolin binders increased. The filler effect resulting from the fine powder of both binders was seen to ameliorate substantially the resistance to chemical attacks in comparison with ordinary concrete. Durability tests also verified that concrete using metakaolin bore most of the mechanical and durability characteristics exhibited by concrete using silica fume. The tests implemented in this study confirmed that metakaolin constitutes a promising material as a substitute for the cost prohibitive silica fume.     

聚羧酸系高效减水剂对海工自密实高性能混凝土性能的影响

研究了聚羧酸系减水剂配制的海工自密实高性能混凝土的拌合物性能、抗压强度和抗氯盐侵蚀性能.试验结果表明,四种聚羧酸系高效减水剂与海工自密实高性能混凝土胶凝材料的适应性良好,配制的海工自密实高性能混凝土拌合物性能良好,且具有较高的抗压强度和耐久性,能满足海工混凝土结构耐久性的要求.     

C80自密实高性能混凝土的试验研究与应用

本文采用聚羧酸系高效减水剂,通过对硅灰、粉煤灰及矿渣粉不同组合的试验研究,在不掺加硅灰的情况下,配制出成本低廉、工作性能良好的C80级自密实混凝土,并在工程中成功应用。