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混凝土研究
余海跃1,隆 锐1,田 波2,李志远2,罗志辉2,李立辉2,*
摘 要:为了研究在-10 ℃环境下硅酸盐-铝酸盐-磷酸盐水泥体系(SAP体系)的水化反应情况,通过凝结时间、XRD、TG、SEM等测试分析了SAP体系的水化产物和反应机理。结果表明:掺入铝酸盐水泥(CAC)和焦磷酸钠均有利于硅酸盐水泥(OPC)的早期凝结,但不利于其后期强度发展;SAP体系早期的主要水化产物为C-S-H凝胶和NO2-AFm晶体,CAC掺量越多,7 d水化产物生成量越多,试件的抗压强度越高;7~28 d时,CAC掺量为10%的S9A1P体系中Ca(OH)2晶体持续生成,试件28 d抗压强度达到32.4 MPa。
Abstract: In order to study the hydration reaction of the silicate-aluminate-phosphate cement system(SAP system) at -10 ℃, the hydration products and reaction mechanism of the SAP system were analyzed through tests such as setting time, XRD, TG, SEM, etc. The results show that The addition of aluminate cement(CAC) and sodium pyrophosphate is beneficial for the early setting of ordinary Portland cement(OPC), but not conducive to its later strength development. In the SAP system, the main early hydration products are C-S-H gel and NO2-AFm crystal. The more CAC is added, the more hydration products are generated at 7 d, and the higher the compressive strength of the specimen is. At 7~28 d, Ca(OH)2 crystals continue to form in the S9A1P system with a CAC content of 10%, and the compressive strength of the specimen reaches 32.4 MPa at 28 d.
余海跃,隆锐,田波,等.负温条件下硅酸盐-铝酸盐-磷酸盐水泥体系水化机理研究[J].混凝土与水泥制品,2023(12):44-49.
YU H Y,LONG R,TIAN B,et al.Study on hydration mechanism of silicate-aluminate-phosphate cement system at negative temperature[J].China Concrete and Cement Products,2023(12):44-49.
周爱萍1,2,葛 刚2,宋子健3,*,刘 浪3
摘 要:综述了杂散电流的形成、作用机理和复杂环境下杂散电流对钢筋混凝土性能的影响以及防治方法。首先,分析了杂散电流形成的主要原因及作用机理;其次,阐述了杂散电流与其他多因素耦合作用下对钢筋混凝土性能的影响;然后,列举了目前国内外防治轨道交通混凝土杂散电流的主要措施;最后,指出了关于复杂环境下轨道交通混凝土杂散电流仍需进一步研究的问题。
Abstract: The formation and mechanism of stray current, the impact of stray current on the performance of reinforced concrete in complex environments, and its prevention methods are summarized. Firstly, the main reasons and mechanism of stray current formation are analyzed. Secondly, the impact of stray current and other multiple factors coupling on the performance of reinforced concrete is elaborated. Then, the main measures for preventing stray current in rail transit concrete at home and abroad are listed. Finally, it is pointed out that further research is needed on the stray current in concrete of rail transit in complex environments.
周爱萍,葛刚,宋子健,等.复杂环境下轨道交通混凝土杂散电流及其防治方法研究进展[J].混凝土与水泥制品,2023(12):39-43.
ZHOU A P,GE G,SONG Z J,et al.Research progress on stray current of rail transit concrete in complex environment and its prevention methods[J].China Concrete and Cement Products,2023(12):39-43.
徐冬冬,程 浩,万 菲,朱云飞,闫雯雯,冯 超*
摘 要:综述了不同工程领域混凝土结构损坏和产生裂缝的原因,针对不同裂缝介绍了灌浆修复材料在原材料选择、配合比、施工方式方面的不同,总结了灌浆修复材料自身性能和修复后基体结构整体性能的提升,最后,对研发新型、环保、高效的灌浆修复材料进行了展望。
Abstract: The reasons for concrete structural damage and cracks in different engineering fields are elucidated, and the differences in raw material selection, mix proportion, and construction methods of grouting repairing materials are introduced for different cracks. The performance of grouting repairing materials and the improvement of overall structural performance after repair are summarized. Finally, the development of new, environmentally friendly, and efficient grouting repairing materials is prospected.
徐冬冬,程浩,万菲,等.灌浆修复材料在工程领域的研究进展[J].混凝土与水泥制品,2023(12):34-37.
XU D D,CHENG H,WAN F,Research progress of grouting repairing materials in engineering field[J].China Concrete and Cement Products,2023(12):34-37.
逄鲁峰1,2,安昊文1,3,*,孙立刚2,黄凌苗2,庞伟琪2,赵 勇2
摘 要:以乙二醇单乙烯基聚乙二醇醚(EPEG)为大单体,丙烯酸(AA)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)为小单体,以双氧水与抗坏血酸作为氧化还原体系,巯基乙醇与次磷酸钠(NaH2PO2)作为链转移剂,合成了聚羧酸减水剂PC-220。通过单因素试验确定了最佳反应参数为底釜pH=5、滴加时间1 h。基于响应面设计方法建立了二次多项式回归方程,以石膏净浆流动度与水泥净浆流动度为响应值,进行响应面优化后,确定了酸醚比为4.24,NaH2PO2用量为0.33%,AMPS用量为0.66%。优化后掺PC-220的石膏净浆流动度相对误差为1.3%、水泥净浆流动度相对误差为0.8%,表明响应面优化可行。应用结果表明,合成的PC-220在水泥基灌浆料与石膏自流平中的使用效果优于PC-530与PC-570。
Abstract: Polycarboxylate superplasticizer PC-220 was synthesized from ethylene glycol monovinyl polyethylene glycol ether (EPEG) as large monomer, acrylic acid (AA), 2-acrylamide-2-methylpropyl sulfonic acid (AMPS) as small monomer, hydrogen peroxide and ascorbic acid as redox system, mercaptoethanol and sodium hypophosphate(NaH2PO2) as chain transfer agent. The optimum reaction parameters were determined by single factor test, with pH=5 of bottom kettle and adding time 1 h. The quadratic polynomial regression equation was constructed based on the response surface design method. The response surface optimization was carried out to determine the acid-ether ratio of 4.24 with the net slurry fluidity of gypsum and cement as the response values. The dosage of NaH2PO2 was 0.33% and AMPS was 0.66%. After optimization, the relative error of the fluidity of gypsum slurry mixed with PC-220 is 1.3%, and the relative error of cement slurry fluidity is 0.8%, indicating that response surface optimization is feasible. The application results show that the use effect of synthesized PC-220 in cement-based grouting materials and gypsum self-leveling is better than those of PC-530 and PC-570.
逄鲁峰,安昊文,孙立刚,等.基于响应面法的聚羧酸减水剂优化合成及应用研究[J].混凝土与水泥制品,2023(12):1-7.
PANG L F,AN H W,SUN L G,et al.Optimization synthesis and application research of polycarboxylate superplasticizer based on response surface method[J].China Concrete and Cement Products,2023(12):1-7.
孟 龙1,袁文华1,2,纪连杰1,方 敏1,张祥驰1
摘 要:将蔗糖和柠檬酸按质量比1∶5配制成复合缓凝剂,通过L9(34)正交试验,研究了水胶比(0.30、033、0.36)、砂率(31%、35%、39%)、粉煤灰掺量(10%、20%、30%)、复合缓凝剂掺量(0.15%、0.20%、0.25%)对混凝土坍落度、终凝时间及抗压强度的影响。结果表明:随着水胶比的增大,混凝土的坍落度先增大后减小,终凝时间延长,抗压强度降低;砂率对混凝土坍落度和终凝时间的影响较小,但对混凝土抗压强度的影响较大;粉煤灰掺量对混凝土坍落度、终凝时间和抗压强度的影响均较小;随着复合缓凝剂掺量的增加,混凝土的坍落度增大,终凝时间延长,抗压强度变化较小;实际应用时,可根据工程要求选择合适的水胶比、砂率、粉煤灰掺量和复合缓凝剂掺量。
Abstract: The composite retarder was prepared by mixing sucrose and citric acid in the mass ratio of 1∶5, and the effects of water cement ratio (0.30, 033, 0.36), sand ratio (31%, 35%, 39%), fly ash content (10%, 20%, 30%), and composite retarder content (0.15%, 0.20%, 0.25%) on the slump, final setting time and compressive strength of concrete were investigated by the L9(34) orthogonal test. The results show that with the increase of water cement ratio, the slump of concrete first increases and then decreases, the final setting time is prolonged, and the compressive strength decreases. The sand ratio has a smaller effect on the slump and final setting time of concrete, but has a larger effect on the compressive strength of concrete. The effect of fly ash content on the slump, final setting time and compressive strength of concrete is relatively small. With the increase of composite retarder content, the slump of concrete increases, the final setting time prolongs, and the changes in compressive strength are relatively small. When applied in practice, the suitable water cement ratio, sand ratio, fly ash content and composite retarder content can be selected according to the requirements of the project.
孟龙,袁文华,纪连杰,等.掺蔗糖-柠檬酸复合缓凝剂混凝土性能的研究[J].混凝土与水泥制品,2023(12):8-10,16.
MENG Long, YUAN Wenhua, JI Lianjie,et al.Study on the performance of concrete mixed with sucrose-citric acid composite retarder[J].China Concrete and Cement Products,2023(12):8-10,16.
李新星1,2,李水生1,2
摘 要:为研究粉煤灰部分取代硅灰、石英粉部分取代石英砂对超高性能混凝土(UHPC)性能的影响,进行了UHPC抗压强度、抗折强度、抗拉强度和流动性试验。结果表明:随着粉煤灰取代硅灰比例的增加,UHPC的抗折强度和抗拉强度提高,流动性降低,但当粉煤灰取代率超过10%时,UHPC的抗压强度降低;UHPC的抗折强度和抗拉强度随着石英粉取代石英砂比例的增加而提高,当石英粉取代率为10%时,UHPC的抗压强度最大;当石英粉取代率为30%时,抗折强度和抗拉强度分别提高了56.5%和24.4%;UHPC的流动性随着石英粉取代率的增加而降低;当粉煤灰取代率为30%、石英粉取代率为15%、水胶比为0.18时,UHPC的力学性能和工作性最佳。
Abstract: In order to study the effect of fly ash partial replacement of silica fume and quartz powder partial replacement of quartz sand on the properties of ultra-high performance concrete(UHPC), the compressive strength, flexural strength, tensile strength and fluidity tests of UHPC were carried out. The results show that the flexural strength and tensile strength of UHPC increase with the increase of the proportion of silica fume, and the fluidity decreases. When the replacement rate of fly ash exceeds 10%, the compressive strength of UHPC decreases. The flexural strength and tensile strength of UHPC increase with the increase of quartz powder replacement rate. When the quartz powder replacement rate is 10%, the compressive strength of UHPC is the highest. When the replacement rate of quartz powder is 30%, the flexural strength and tensile strength are increased by 56.5% and 24.4% respectively. The fluidity of UHPC decreases with the increase of quartz powder replacement rate. When the replacement rate of fly ash is 30%, the replacement rate of quartz powder is 15% and the water-binder ratio is 0.18, UHPC has the best mechanical properties and workability.
李新星,李水生.粉煤灰和石英粉对超高性能混凝土性能的影响[J].混凝土与水泥制品,2023(12):11-16.
LI X X,LI S S.Effect of fly ash and quartz powder on properties of ultra-high performance concrete[J].China Concrete and Cement Products,2023(12):11-16.