粒化高炉矿渣粉在混凝土中的应用

从粒化高炉矿渣粉的基本概念出发,通过对照高价标准,对粒化高炉矿渣粉在混凝土中的作用原理进行了分析,提出了在实际混凝土中应用高炉矿渣粉应该注意的几个问题,以指导实践。     

钢渣矿渣复合粉在商品混凝土中的应用研究

本文研究了钢渣矿渣复合粉取代矿渣粉作为商品混凝土掺合料,对混凝土工作性和抗压强度的影响。试验结果表明:采用复合粉取代矿粉对混凝土的工作性和抗压强度无不利的影响,采用复合粉取代矿渣粉作为混凝土掺合料具有良好的经济社会效益。     

粒化高炉矿渣代砂混凝土力学性能试验

研究了粒化高炉矿渣作为混凝土细骨料时的基本特性及其不同代砂率混凝土的物理力学性能。结果表明:粒化高炉矿渣与天然砂在化学成分及物理性能方面存在一定差异。在相同水胶比的条件下,相比于普通混凝土,粒化高炉矿渣代砂混凝土的流动性较差且含气量较高;与普通混凝土相比,粒化高炉矿渣代砂混凝土早期抗压强度较低但其后期强度增长较快,且粒化高炉矿渣代砂率越高后期强度增长越快;粒化高炉矿渣代砂混凝土劈裂抗拉强度和普通混凝土较为接近;粒化高炉矿渣代砂混凝土28 d弹性模量和普通混凝土较为接近且随混凝土强度等级的提高而增加。     

磨细矿粉和预水化粉煤灰在混凝土中的应用

目前混凝土中掺加粉煤灰和磨细矿粉已成为降低成本、改善性能的主要手段之一.但预水化粉煤灰在混凝土中的应用研究较少.通过对复合掺加预水化粉煤灰和磨细矿粉的混凝土性能进行研究,结果表明,磨细矿粉的细度对混凝土的物理力学性能有重要影响,从技术和经济上综合考虑,磨细矿粉细度为7 600cm2/g时较为理想,混凝土中预水化粉煤灰和磨细矿粉的掺量存在最佳范围,双掺时,预水化粉煤灰掺量为15%,磨细矿粉掺量为40%,此时混凝土28d抗压强度提高16%左右,这对节约能源和资源、改善环境具有重要的现实意义及良好的经济效益和社会效益.     

钢渣-矿渣复合微粉的活性试验研究

研究了改变钢渣与矿渣微粉比例以及钢渣微粉比表面积对混合材的机械激发性能,同时考察了自行研制的KYH-8、KYH-9和KYH-10三种激发剂对复合微粉的化学激发,并通过X射线衍射(XRD)、偏光显微(PLM)和电子扫描电镜(SEM)对复合微粉材料进行了结构分析.试验结果表明,复合渣微粉中钢渣的比例越大,钢渣矿渣复合粉的活性越低;钢渣微粉比表面积在400～500m2/kg时,钢渣微粉细度增加,复合微粉活性有所提高;复合微粉在早期只是填充于水泥石之间,起填充剂的作用,后期逐渐水化;0.01 mol/L KYH-10激发剂对钢渣与矿渣微粉比例为3:2的复合微粉激发效果表现最佳,复合微粉7d活性指数达到85%以上,28 d活性指数可以达到104%.     

粉煤灰、矿渣的粉磨对水泥性能的影响

研究了粉煤灰及高炉矿渣经不同粉磨工艺处理后,对所掺杂水泥的凝结时间及强度发展的影响。结果表明：粉煤灰磨细后,会延长水泥的实际凝结时间并提升后期强度,而高炉矿渣磨细后,水泥的实际凝结时间缩短,早期强度得到改善。但粉磨时间过长,则会使微细颗粒重新产生团聚,影响产品的实际性能。     

Performance of ground blast furnace slag and ground basaltic pumice concrete against seawater attack

The aim of this research work is to investigate the seawater resistance of the concrete incorporating ground blast furnace slag (GBS) and ground basaltic pumice (GBP) each separately or both together. The variable investigated in this study is the level of fine aggregate replacement by GBS and GBP. Compressive strength measured on 150 mm cubes was used to assess the changes in the mechanical properties of concrete specimens exposed to seawater attack for 3 years.

Differential scanning calorimeter was used to evaluate the microstructure of the specimens under seawater attack. The effects of exposure were determined by direct measurement of the mass loss of steel bars, embedded in the mortar after 1, 2 and 3 years. The abrasion of concrete was also determined according to mass loss of specimens.

The test results showed that the presence of GBS and GBP had a beneficial effect on the compressive strength loss due to seawater attack and abrasion value. The results create perspectives of forecasting the durability of concrete depending on the types and amount of additives. Furthermore, specimen CSP80 was found to have higher seawater attack resistance than that of the reference concrete. This improvement can be explained partly by the decrease in the permeability of the specimen and partly by the seawater resistance of the additives. Additionally, the corrosion percentage obtained in the reference specimen was higher than all other specimens.     

混凝土配合比设计在高炉粒化矿渣路面砖配合比设计中的应用*

以利用高炉粒化矿渣制备路面砖为例,借鉴混凝土配合比设计规程设计路面砖的配合比。先参照混凝土配合比设计规程设计一个的常规的混凝土配合比,再分别用粗砂代替石子和砂,再用高炉粒化矿渣代替粗砂,然后用粉煤灰调整骨料与细粉料的配比,再微调水泥等组分,设计出高炉粒化矿渣路面砖的配合比。     

镍渣矿渣免烧砖的试验研究

研究了镍渣矿渣比和水泥掺量对镍渣矿渣复合胶凝材料体系的影响,并在此基础上,辅以化学激发剂NS、CA,采用正交试验方法,研制开发新型镍渣矿渣基复合胶凝材料,最佳配比为:镍渣和矿渣的质量比5∶5,水泥、激发剂NS和CA分别占镍渣和矿渣总质量的20％、0.5％和2％,胶砂比1∶3,水胶比0.5,可制得符合MU25等级的免烧砖.     

Strength and drying shrinkage properties of concrete containing furnace bottom ash as fine aggregate

The strength and drying shrinkage of concretes with the natural sand replaced with furnace bottom ash (FBA) at 0%, 30%, 50%, 70% and 100% by mass, were studied at fixed water–cement ratios (W/C) and fixed slump ranges.The results showed that, at fixed water–cement ratios, the compressive strength and the drying shrinkage decreased with the increase of the FBA sand content. However, at fixed workability, the compressive strength was comparable with that of the control concrete, while the drying shrinkage increased with the increase of the FBA sand content beyond 30% replacement level. Nevertheless, 30% of the natural sand can be beneficially replaced with the FBA sand to produce concrete in the compressive strength range from 40 to 60 N/mm² without detrimentally affecting drying shrinkage properties of the concrete.     

Splitting tensile strength of concrete using ground granulated blast furnace slag and SiO2 nanoparticles as binder

In the present study, split tensile strength together with pore structure, thermal behavior and microstructure of concrete containing ground granulated blast furnace slag and SiO₂ nanoparticles have been investigated. Portland cement was replaced by different amounts of ground granulated blast furnace slag and the properties of concrete specimens were measured. Although it negatively impacts the properties of concrete at early ages, ground granulated blast furnace slag was found to improve the physical and mechanical properties of concrete up to 45 wt% at later ages. SiO₂ nanoparticles with the average particle size of 15 nm were partially added to concrete with the optimum content of ground granulated blast furnace slag and physical and mechanical properties of the specimens were studied. SiO₂ nanoparticle as a partial replacement of cement up to 3 wt% could accelerate C-S-H gel formation as a result of increased crystalline Ca(OH)₂ amount at the early age of hydration and hence increase split tensile strength of concrete specimens. The increased the SiO₂ nanoparticles’ content more than 3 wt% causes the reduced the split tensile strength because of the decreased crystalline Ca(OH)₂ content required for C-S-H gel formation. SiO₂ nanoparticles could improve the pore structure of concrete and shift the distributed pores to harmless and few-harm pores.     

水玻璃的模数和掺量对钢矿粉活性影响研究

研究了水玻璃的模数和掺量对钢矿粉活性的影响,结果表明,当钢渣与矿渣比例为3∶7时,钢矿粉各龄期活性随水玻璃模数、掺量的提高呈先升后降趋势,当水玻璃模数为1.6,掺量为胶凝材料的1.5%时,钢矿粉3 d,7 d,28 d活性指数分别提高10%,11%,5%。     

Clayey soil stabilization using alkali-activated volcanic ash and slag

Lime and Portland cement are the most widely used binders in soil stabilization projects. However, due to the high carbon emission in cement production, research on soil stabilization by the use of more environmentally-friendly binders with lower carbon footprint has attracted much attention in recent years. This research investigated the potential of using alkali-activated ground granulated blast furnace slag (GGBS) and volcanic ash (VA) as green binders in clayey soil stabilization projects, which has not been studied before. The effects of different combinations of VA with GGBS, various liquid/solid ratios, different curing conditions, and different curing periods (i.e. 7 d, 28 d and 90 d) were investigated. Compressive strength and durability of specimens against wet-dry and freeze-thaw cycles were then studied through the use of mechanical and microstructural tests. The results demonstrated that the coexistence of GGBS and VA in geopolymerization process was more effective due to the synergic formation of N-A-S-H and C-(A)-S-H gels. Moreover, although VA needs heat curing to become activated and develop strength, its partial replacement with GGBS made the binder suitable for application at ambient temperature and resulted in a remarkably superior resistance against wet-dry and freeze-thaw cycles. The carbon embodied of the mixtures was also evaluated, and the results confirmed the low carbon footprints of the alkali-activated mixtures. Finally, it was concluded that the alkali-activated GGBS/VA could be promisingly used in clayey soil stabilization projects instead of conventional binders.     

粉煤灰与矿渣对再生骨料混凝土力学性能影响的研究

研究了粉煤灰单掺、粉煤灰与矿渣双掺对再生骨料混凝土(RAC)力学性能的影响,并初步探讨了其影响机理;建立了再生骨料混凝土立方体抗压强度与抗折强度、劈拉强度的相关关系式。试验结果表明：粉煤灰单掺降低了再生骨料混凝土的强度和弹性模量;粉煤灰与矿渣双掺对混凝土强度和弹性模量的影响随两者组合比例不同而有显著差异。     

钢渣复合掺合料配制混凝土的工作性能与力学性能研究

研究了钢渣复合掺合料配制混凝土的工作性能与力学性能,并从掺合料的相组成、水化特性、形貌特征、稀释效应及体积效应的角度对试验结果进行了综合分析。研究结果表明,不同掺量下钢渣对混凝土工作性能的影响不同,钢渣-矿渣复合掺合料对混凝土的工作性能有明显不利影响；钢渣的早期活性优于矿渣及粉煤灰,后期略低于矿渣但仍明显优于粉煤灰;高掺量下钢渣与矿渣有良好的复合超叠加效应，且二者的最佳比例为3：7。     

磨细矿粉改性及其助磨剂试验研究

通过试验小磨研究了助磨剂石膏、早强剂三乙醇胺对矿渣粉比表面积、粒度分布、活性指数、颗粒形貌等性能的影响。研究表明，石膏3％掺量下对高炉矿渣有明显的助磨效果，矿粉平均粒径下降到4．02μm。最大粒径13．5μm。三乙醇胺在0．8‰掺量下对磨细矿粉有较明显的早期活性增强作用，其机理与其能加速水泥早期水化速率有关。     

Properties of concrete prepared with crushed fine stone,furnace bottom ash and fine recycled aggregate as fine aggregates

This paper presents the results of a study to compare the properties of concretes prepared with the use river sand, crushed fine stone (CFS), furnace bottom ash (FBA), and fine recycled aggregate (FRA) as fine aggregates. Two methods were used to design the concrete mixes: (i) fixed water–cement ratio (W/C) and (ii) fixed slump ranges. The investigation included testing of compressive strength, drying shrinkage and resistance to chloride-ion penetration of the concretes. The test results showed that, at fixed water–cement ratios, the compressive strength and the drying shrinkage decreased with the increase in the FBA content. FRA decreased the compressive strength and increased the drying shrinkage of the concrete. However, when designing the concrete mixes with a fixed slump value, at all the test ages, when FBA was used as the fine aggregates to replace natural aggregates, the concrete had higher compressive strength, lower drying shrinkage and higher resistance to the chloride-ion penetration. But the use of FRA led to a reduction in compressive strength but increase in shrinkage values. The results suggest that both FBA and FRA can be used as fine aggregates for concrete production.     

生活垃圾焚烧灰渣代砂混凝土配合比及力学性能试验

对生活垃圾焚烧灰渣代砂作为混凝土细骨料进行了试验研究。从有毒物质浸出、筛分、压碎指标等分析了生活焚烧垃圾灰渣的骨料特性,并对5种水胶比、3种代砂率的生活垃圾焚烧灰渣细骨料混凝土进行了配合比试验及力学性能试验。试验结果表明,生活垃圾焚烧灰渣多孔、吸水率高、压碎指标低,具有一定的潜在水硬性;通过增加减水剂等合理配合比设计,可以配出工作性能满足工程要求的生活垃圾焚烧灰渣细骨料混凝土;生活垃圾焚烧灰渣细骨料混凝土强度要低于同配合比条件的普通天然砂混凝土,尤其是100%代砂率焚烧灰渣混凝土28 d抗压强度仅为普通天然砂混凝土的一半左右,50%代砂率焚烧灰渣混凝土抗压强度更接近普通天然砂混凝土。     

矿渣微粉在水泥混凝土中应用的概述

对用作混凝土掺合料的矿渣微粉的主要技术条件与矿渣微粉混凝土的主要性能特征作了简要的介绍。对矿渣微粉用于混凝土中的工作机理进行了探讨。最后提出矿渣微粉在水泥制品生产中应得到开发应用。     

高效减水剂与矿渣-钢渣复合掺合料的适应性研究

为了加快高性能矿渣-钢渣基复合掺合料的开发和应用,本工作研究了萘系减水剂和聚羧酸两类减水剂与钢渣和硅酸盐水泥三种矿粉之间的适应性。研究表明：对于矿渣、钢渣和硅酸盐水泥三种矿粉的单组分净浆,各种减水剂的饱和掺量在0．3％～1．1％之间。萘系高效减水剂掺量过大,胶砂和混凝土离析泌水严重,硬化体的强度显著下降。聚羧酸盐减水剂的突出优势是使净浆、砂浆和混凝土的流动度和稳定性俱佳,但混凝土强度低于掺萘系高效减水剂的混凝土。