碱矿渣水泥砂浆的碱集料反应膨胀研究

通过测长试验,研究了三类碱矿渣水泥(AASC)砂浆的碱集料反应(AAR)引起的膨胀;分析了碱组分种类、碱质量分数、活性集料质量分数和矿渣种类等因素对AASC砂浆AAR膨胀率的影响.综合宏观和微观测试结果,探讨了碱矿渣混凝土的碱集料反应机理.结果表明,AASC系统出现危险性碱集料反应的可能性远低于普通水泥系统.     

碱集料反应对混凝土结构的破坏及化学抑制措施

本文简述了混凝土结构中碱集料反应的破坏现象及其抑制措施。碱集料反应包括碱硅酸反应和碱碳酸反应等两种化学侵蚀现象。碱集料反应的检测技术包括岩相法(RILEM标准)、砂浆棒快速法(ASTM标准)、混凝土棱柱体法(CSA标准)等。碱集料反应矿物掺合料抑制技术和化学外加剂技术，其中矿物掺合料技术包括粉煤灰和矿渣等混凝土结构常用矿物掺合料，化学外加剂技术主要涉及锂盐外加剂。最后对混凝土结构中碱集料反应的研究与应用发展方向进行了展望。     

G级中抗油井水泥的研制与开发

为满足市场需求,充分发挥我厂作为特种水泥生产基地的优势,经过市场调研,决定研制开发Ｇ级中抗油井水泥。　　　　油井水泥国家标准ＧＢ１０２３８－１９９８中将该品种分为　Ａ、Ｂ、Ｃ、Ｄ、Ｅ、Ｆ、Ｇ、Ｈ八个级别,其中Ｃ级属基本油井水泥,分为中抗硫酸盐（ＭＳＲ）和高抗硫酸盐（ＨＳＲ）型。１　原燃材料配料方案的设计质量要求　　　　国家标准ＧＢ－１０２３８－１９９８中规定,中抗Ｇ级油井水泥中Ｃ３Ｓ含量为４８％～５８％,Ｃ３Ａ≤８％,碱含量≤０．７５％。参考有关资料,综合考虑强度、稠度及稠化时间等因素,我厂将水…     

陶瓷抛光渣对水泥基材料碱集料反应的影响

以0%、20%、30%、40%陶瓷抛光渣等量取代水泥制备砂浆试样,矿渣作对比试验,通过膨胀率、强度测定、扫描电子显微镜观察和能谱分析,研究陶瓷抛光渣对水泥基材料碱集料反应的影响规律,揭示矿物掺合料抑制碱集料反应的机理。结果表明:陶瓷抛光渣能有效抑制水泥基材料的碱集料反应膨胀,且其抑制作用比矿渣更显著;两种掺合料使集料与胶凝材料界面区结构更密实,界面宽度更小;抛光渣的合理掺量为20%～30%、矿渣掺量应30%。矿物掺合料抑制碱集料反应的机理为界面过渡区中Ca/Si比降低使集料表面碱度降低,降低了近集料区域生成高Na/Si比膨胀性产物的可能性,并且K+和Al~(3+)在近集料处富集,形成非膨胀性产物。由于体系中Al_2O_3的存在,使K+对碱集料反应的作用低于Na+的作用。     

碱对含C4A3S↑—型水泥熟料的影响

本文利用天然原料、高碱工业废渣制成含碱的Ｃ４Ａ３Ｓ↑－系列水泥并借助于ＸＲＤ、ＳＥＭ及强度测试等手段研究了碱对含Ｃ４Ａ３Ｓ↑－型水泥熟料煅烧及相应水泥物理性能的影响。研究表明，碱含量的增加不仅使此类水泥的后期强度降低，也使其早期强度降低，但与普通硅酸盐水泥相比，降低的幅度要小。因此可以利用高碱原料或工业废渣生产含Ｃ４Ａ３Ｓ↑－型的水泥或胶凝材料。     

矿渣代粘土配料生产低碱熟料的烧成试验

为了减轻水泥的碱集料反应、改善水泥的耐久性，生产低碱水泥熟料是大势所趋。D公司在生产低碱水泥熟料的过程中，原料碱含量有时偏高，不能满足生产品质需要。经调查，BG公司的矿渣碱含量较低，经过充分研讨，D公司进行了在原料配料中．用矿渣代粘土生产低碱水泥熟料的烧成试验。本文就该试验作一介绍，供参考。     

碱对含C_4A_3S型水泥熟料的影响

本文利用天然原料、高碱工业废渣制成含碱的Ｃ_４Ａ_３Ｓ系列水泥并借助于ＸＲＤ、ＳＥＭ及强度测试等手段研究了碱对含Ｃ_４Ａ_３Ｓ型水泥熟料燃烧及相应水泥物理性能的影响。研究表明，碱含量的增加不仅使此类水泥的后期强度降低，也使其早期强度降低，但与普通硅酸盐水泥相比，降低的幅度要小。因此可以利用高碱原料或工业废渣生产含Ｃ_４Ａ_３Ｓ型的水泥或胶凝材料。     

硅质集料碱活性快速砂浆棒试验方法 1.试验温度与水泥碱含量对砂浆膨胀的影响

研究了养护温度和水泥碱含量（质量分数，下同）与硅质集料砂浆试样膨胀的关系。温度对砂浆膨胀影响较大，采用８０℃碱溶液养护，试验更迅速，结果更敏感。水泥碱含量对砂浆膨胀的规律影响较小，但对膨胀值有明显影响。采用加碱方法调整水泥碱含量可以有效地控制试验条件，使试验更迅速、准确     

碱胶凝材料形成的物理化学基础（Ⅱ）

碱胶凝材料形成的物理化学基础（Ⅱ）杨南如（南京化工大学）（第Ⅰ部份请见本卷第２期）４碱胶凝材料的水化产物４．１产物种类多数学者认为碱矿渣水泥的水化产物主要有Ｃ－Ｓ－Ｈ凝胶、铝酸钙等与硅酸盐水泥相似的水化产物。禹尚仁［４５］还发现存在水化铝硅酸钙ＣａＯ...     

催化合成水杨酸酯的工艺研究

芳基磺酸（ＡＳＡ） 催化水杨酸（２ 羟基苯甲酸） 和Ｃ４ ～Ｃ５ 醇的酯化反应,性能优于磷钨酸等其他４ 种催化剂。探讨并找到了ＡＳＡ催化合成水杨酸丁酯、戊酯的优化反应条件：原料配比ｎ（Ｃ７Ｈ６Ｏ３）∶ｎ（ＲＯＨ）＝１∶１－８,催化剂ＡＳＡ的用量为酸质量的５ ％ ～７％ ,反应温度１１０ ～１４０ ℃,反应时间４～７ ｈ,转化率达９２％ ～９７％ ,产品纯度大于９９％ 。     

The alkali-silica reaction in alkali-activated granulated slag mortars with reactive aggregate

The expansion of alkali-activated granulated blast furnace slag (AAS) cement mortars with reactive aggregate due to alkali-silica reaction (ASR) was investigated. The alkaline activator used was NaOH solution with 4% Na₂O (by mass of slag). These results were compared to those of ordinary portland cement (OPC) mortars. The ASTM C1260-94 Standard Test Method based on the NBRI Accelerated Test Method was followed. The nature of the ASR products was also studied by SEM/EDX. The results obtained show that the AAS cement mortars experienced expansion due to the ASR, but expansion occurs at slower rate than with OPC mortars under similar conditions. The cause of the expansion in AAS cement mortars is the formation of sodium and calcium silicate hydrate reaction products with rosette-type morphology. Finally, in order to determine potential expansion due to ASR, the Accelerated Test Method is not suitable for AAS mortars because the reaction rate is initially slow and a longer period of testing is required.     

混合材料微粉对水泥砂浆性能的影响

用不同掺量的矿渣粉及粉煤灰对水泥砂浆流动性和抗压强度进行了试验研究。结果表明：矿渣粉和粉煤灰都可以提高砂浆的流动性,它们对水泥砂浆的流动度及抗压强度的影响与水泥品种及砂浆配合比有关。     

The influence of potassium-sodium ratio in cement on concrete expansion due to alkali-aggregate reaction

In concrete containing potentially reactive aggregates, deleterious alkali-aggregate-reaction (AAR) can be prevented by the use of suitable mineral admixtures or by limiting cement content and alkalis (Na₂O-equivalent) of the cement. However, the Na₂O-equivalent of cement may not always accurately define the potential of cement to cause AAR. In this study, the potential reactivity of concrete produced with cements having similar Na₂O-equivalents but different K/Na-ratios has been measured and the composition of gel has been analyzed. Additionally, pastes and mortars have been produced to study the development of pore solution composition.The expansion of the concrete mixtures shows significant differences depending on the cement used. The different K/Na-ratio present in the cements is reflected in the pore solution of pastes and mortars and in the gel present in aggregates of the concrete mixtures. As the hydroxide concentration in the pore solutions of pastes and mortars produced with the different cements is nearly identical, the difference in K/Na-ratio has to be the reason for the observed differences in concrete expansion.     

Compatibility between ecocement produced from incinerator ash and reactive aggregates in ASR expansion of mortars

Recently, in Japan, two new-type hydraulic cements, high early strength type ecocement (HEC) and normal type ecocement (NEC), have been developed using incinerator ashes up to 50% of the raw materials. In this study, the compatibility of these ecocements with various types of reactive aggregates with respect to alkali-silica reaction (ASR) was studied. Ordinary Portland cement (OPC) and blast furnace slag cement (BFSC) were also used for a comparative study. Two types of the accelerated mortar bar expansion test, the JIS A1146 and the Danish methods, were used to clarify the expansion behavior of mortars made with the above cements. The influence of a combination of the chemical and mineralogical compositions of cement and the reactive components of aggregate on both the amount of ASR gel and the expansion rate of the mortar was also investigated. From the results, it was found that the expansion behaviors of mortars due to ASR varied significantly depending on a combination of both the mineralogical composition of cement and the reactive component of aggregate.     

Residual compressive behavior of alkali‐activated concrete exposed to elevated temperatures

This paper reports the effect of elevated temperature exposures, up to 1200^°C , on the residual compressive strengths of alkali‐activated slag concrete (AASC) activated by sodium silicate and hydrated lime; such temperatures can occur in a fire. The strength performance of AASC in the temperature range of 400–800^°C was similar to ordinary Portland cement concrete and blended slag cement concrete, despite the finding that the AASC did not contain Ca(OH)₂ , which contributes to the strength deterioration at elevated temperatures for Ordinary Portland Cement and blended slag cement concretes. Dilatometry studies showed that the alkali‐activated slag (AAS) paste had significantly higher thermal shrinkage than the other pastes while the basalt aggregate gradually expanded. This led to a higher thermal incompatibility between the AAS paste and aggregate compared with the other concretes. This is likely to be the governing factor behind the strength loss of AASC at elevated temperatures. Copyright © 2008 John Wiley & Sons, Ltd.     

激发剂对碱矿渣水泥砂浆中碱-硅酸反应的影响

采用硅酸钠溶液为激发剂制备碱矿渣(AAS)水泥砂浆,在80 ℃的1 mol/L氢氧化钠溶液中养护以加速碱-硅酸反应(ASR)进程,研究了激发剂碱含量和硅酸盐模数对ASR膨胀破坏的影响。结果表明,AAS砂浆中出现了危险性ASR膨胀破坏。激发剂中Na₂O掺量大于4%(质量分数)时,砂浆在14 d龄期的ASR膨胀率超过0.1%,且当激发剂硅酸盐模数在1.2~2.0范围内时膨胀率更大。ASR产物主要分布在集料颗粒表面与AAS凝胶相接触的界面区,附近可观测到明显的裂缝扩展。ASR膨胀破坏同时引发了砂浆抗压强度损失。     

Effect of binder content on the performance of alkali-activated slag concretes

This paper assesses the mechanical and durability performance of concretes produced using alkali silicate-activated ground granulated blast furnace slag as sole binder. Alkali-activated concretes are formulated with 300, 400 and 500 kg slag per m³ of fresh concrete, and their performance is compared with reference concretes produced using Portland cement (OPCC). Regardless of the binder content, the alkali-activated slag concretes (AASC) develop higher compressive strength than the comparable reference concretes. A higher binder content leads to increased strength in both AASC and OPCC at 28 days. However, at 90 days, the performance penalty for low binder content is more significant in the OPCC than AASC samples. Permeability, water sorption and carbonation resistance properties are also improved at higher binder contents. By controlling mix design parameters, it is possible to produce AASC with mechanical strength and durability comparable to conventional Portland cement concretes.     

碱矿渣水泥的结构与性能研究

本文主要研究了激发剂对碱矿渣水泥强度、硬化碱矿渣水泥浆体的孔结构及其水化程度的影响。结果表明：固体硅酸钠是一种性能良好的激发剂，当其掺量为3％时，碱矿渣水泥28天抗压强度达55．6MPa；同时，硬化碱矿渣水泥浆体具有致密的结构，孔隙率仅为17．5％，有利于提高其耐久性；另外，该水泥的早期水化程度较高，后期增长缓慢，有利于长期强度的发展。     

High-slag cement mortars for brickwork and renderings

The suitability of clinker-activated high-slag cement mortars for use in brickwork construction and in rendered finishes, has been investigated. The study was carried out on a slag cement composed of 80% granulated slag, 15% clinker and 5% raw gypsum; its specific surface area was 4000 cm²/g. It was found that the slag cement mortars and cement-lime mortars of the proportions commonly used in practice, have higher water-retentivity than the corresponding mortars of ordinary Portland cement, and that their strengths are comparable to those of the latter mortars.     

碱矿渣水泥的收缩与开裂特性及其减缩与增韧

碱矿渣水泥是具有高强、高耐久性的胶凝材料,但其收缩大,易开裂,是阻碍其广泛应用的主要原因。通过与通用硅酸盐水泥对比,综合评述碱矿渣水泥的收缩与开裂特点及碱矿渣水泥的减缩与增韧的研究现状与存在问题,分析碱矿渣水泥收缩大,易开裂的主要原因,提出了通过掺入膨胀剂、纤维、矿物颗粒和喷洒减缩剂对碱矿渣水泥进行减缩与增韧的建议。