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第七期
王 旭1,付建鹏1,金冰欣2,朱 斌1,武双磊2,*,徐 迅3
摘 要:以普通硅酸盐水泥、脱硫石膏、矿渣等制备了活性粉末混凝土(RPC),研究了养护温度(20、45、70 ℃)和脱硫石膏掺量(2%~7%)对RPC强度和膨胀率的影响,并进行了XRD和SEM分析。结果表明:当养护温度为20 ℃时,随着脱硫石膏掺量的增加,试件的28 d抗折与抗压强度均先增大后减小;当养护温度为45 ℃时,随着脱硫石膏掺量的增加,试件的28 d抗折强度增大,28 d抗压强度先增大后减小;当养护温度为70 ℃时,试件的28 d抗折与抗压强度均增大;当脱硫石膏掺量相同时,随着养护温度的提高,试件的28 d抗折与抗压强度基本呈增大趋势;脱硫石膏掺量越高,试件的膨胀率越大;养护温度越高,试件趋于稳定时的膨胀率越低;在RPC中掺入适量石膏,并辅以适宜的养护温度,可有效加快水泥和矿渣的水化进程,生成钙矾石,进而改善RPC的强度和膨胀性能。
Abstract: Reactive powder concrete(RPC) was prepared by using ordinary Portland cement, desulfurization gypsum, slag, etc. The effects of curing temperature (20, 45, 70 ℃) and desulfurization gypsum content (2%~7%) on the strength and expansion rate of RPC were studied, and XRD and SEM analysis were conducted. The results show that when the curing temperature is 20 ℃, with the increase of desulfurization gypsum content, the 28 d flexural strength and compressive strength of the specimen first increase and then decrease. When the curing temperature is 45 ℃, with the increase of desulfurization gypsum content, the 28 d flexural strength of the specimen increases and the 28 d compressive strength first increases and then decreases. When the curing temperature is 70 ℃, the 28 d flexural strength and compressive strength of the specimen increase. When the content of desulfurization gypsum is the same, with the increase of curing temperature, the 28 d flexural strength and compressive strength of the specimen basically show an increasing trend. The higher the content of desulfurization gypsum, the greater the expansion rate of the specimen. The higher the curing temperature, the lower the expansion rate of the specimen when it tends to stabilize. Adding an appropriate content of gypsum to RPC, accompanied by an appropriate curing temperature can effectively promote the hydration process of cement and slag, generate ettringite, and improve the strength and expansion properties of RPC.
王旭,付建鹏,金冰欣,等.养护温度与脱硫石膏掺量对RPC性能的影响[J].混凝土与水泥制品,2024(7):83-88.
WANG X,FU J P,JIN B X,et al.Effect of curing temperature and desulfurization gypsum content on performance of RPC[J].China Concrete and Cement Products,2024(7):83-88.
刘远祥1,杨婷丽1,张华献2,孙亚民3,曹鑫铖1,叶国林1,宋秋磊1
摘 要:将粉煤灰和矿粉按不同质量比(m粉煤灰∶m矿粉=7∶3、6∶4、5∶5)制备成了低碳复合辅助性胶凝材料,研究了其等质量替代15%、30%的水泥对胶凝材料需水量比、流动度比和活性指数的影响,优选出了最佳m粉煤灰∶m矿粉。在此基础上,研究了低碳复合辅助性胶凝材料等质量替代0、10%、15%、20%、30%的水泥对胶凝材料标准稠度用水量和凝结时间的影响,以及等质量替代0、10%、20%、30%、40%的水泥对C50混凝土工作性和力学性能的影响。结果表明:在水泥中掺入适量低碳复合辅助性胶凝材料有效改善了胶凝材料体系的工作性,延缓了早期(3 d)水化速度,提高了胶砂7 d、28 d抗压强度,最佳m粉煤灰∶m矿粉为5∶5;随着低碳复合辅助性胶凝材料掺量的增加,胶凝材料的标准稠度用水量变化很小,凝结时间延长;C50混凝土的坍落度随着低碳复合辅助性胶凝材料掺量的增加而增大,7 d和28 d抗压强度先增大后减小,最佳掺量为30%。
Abstract: Low-carbon composite auxiliary cementitious materials were prepared by using fly ash and mineral powder in different mass ratios (mfly ash ∶ mmineral powder =7:3, 6:4, 5:5), and the effects of replacing 15% and 30% of cement with equal mass ratios on the water demand ratio, flowability ratio, and activity index of the cementitious materials were studied, and the optimal mfly ash ∶ mmineral powder was selected. On this basis, the influence of replacing 0, 10%, 15%, 20%, and 30% of cement with low-carbon composite auxiliary cementitious materials on the standard consistency water consumption and setting time of cementitious materials was studied, and the effects of replacing 0, 10%, 20%, 30%, and 40% of cement on the workability and mechanical properties of C50 concrete were studied. The results show that adding an appropriate content of low-carbon composite auxiliary cementitious materials to cement effectively improves the workability of the cementitious materials system, delays the early (3 d) hydration rate, and increases the compressive strength of the mortar at 7 d and 28 d, and the optimal mfly ash ∶ mmineral powder is 5:5. With the increase of low-carbon composite auxiliary cementitious materials content, the standard consistency water consumption of cementitious materials changes very little, and the setting time is extended. With the increase of low-carbon composite auxiliary cementitious materials content, the slump of C50 concrete gradually increases, and the compressive strength at 7 d and 28 d first increases and then decreases, and the optimal content is 30%.
温永钦,李 嘉
摘 要:通过正交试验研究了粉煤灰掺量(10%、15%、20%、25%)、矿粉掺量(15%、20%、25%、30%)、磷石膏掺量(0、2%、4%、6%)对混凝土抗压强度的影响,优选出了最佳掺量,在此基础上,研究了磷石膏掺量(0、2%、4%、6%)对钢管混凝土轴压性能的影响。结果表明:当粉煤灰、矿粉、磷石膏的掺量分别为10%、20%、2%时,混凝土的28 d抗压强度最大;随着磷石膏掺量的增加,钢管混凝土试件的极限承载力先增大后减小,最佳掺量为2%,此时,钢管混凝土试件受压破坏后的横向变形不明显。
Abstract: The effects of fly ash content (10%, 15%, 20%, 25%), mineral powder content (15%, 20%, 25%, 30%), and phosphogypsum content (0, 2%, 4%, 6%) on the compressive strength of concrete were studied through orthogonal experiments, and the optimal content was selected. On this basis, the influence of phosphogypsum content (0, 2%, 4%, 6%) on the axial compression performance of concrete filled steel tube was studied. The results show that when the content of fly ash, mineral powder, and phosphogypsum is 10%, 20%, and 2% respectively, the 28 d compressive strength of concrete is the highest. With the increase of phosphogypsum content, the ultimate bearing capacity of concrete filled steel tube specimen first increases and then decreases, and the optimal content is 2%. Besides, the lateral deformation of concrete filled steel tube specimen after compression failure is not significant.
温永钦,李嘉.磷石膏掺量对钢管混凝土力学性能的影响[J].混凝土与水泥制品,2024(7):94-102.
WEN Y Q,LI J.Effect of phosphogypsum content on mechanical properties of concrete filled steel tube[J].China Concrete and Cement Products,2024(7):94-97,102.
摘 要:将有色冶炼固废提取稀散金属后产生的二次尾渣(以下简称尾渣)作为铁质原料烧制水泥熟料,研究了煅烧温度(1 350、1 400、1 450 ℃)和铝率(1.1、1.3、1.5、1.7)对生料易烧性和熟料物相组成的影响,并优选出最佳煅烧温度和铝率。在此基础上,对比分析了尾渣和铁粉对水泥各项性能的影响,并通过Krustulovic-Dabica水化动力学模型分析了水泥的水化进程。结果表明:尾渣对水泥生料煅烧有一定的矿化作用,最佳煅烧温度和铝率分别为1 400 ℃和1.1;用尾渣作为铁质原料制备的水泥符合GB 175—2023《通用硅酸盐水泥》中P·Ⅰ42.5级水泥的相关要求;与铁粉相比,用尾渣作为铁质原料制备的水泥矿物成分较多,结晶成核和晶体增长阶段的反应程度更高,水化放热量较大,水化反应速率更快,相边界反应阶段的反应时间较短。
Abstract: The secondary tailings slag (hereinafter referred to as tailing slag) produced after the extraction of dilute metals from non-ferrous smelting solid waste was used as iron raw material to burn cement clinker, and the effects of calcination temperature (1 350, 1 400, 1 450 ℃) and aluminum rate (1.1, 1.3, 1.5, 1.7) on the burnability of raw material and the composition of clinker were studied, and the optimal calcination temperature and aluminum rate were selected. On this basis, the effects of tailings slag and iron powder on various properties of cement were analyzed comparatively, and the hydration process of cement was analyzed by using Krustulovic-Dabica hydration kinetic model. The results show that tailings slag has certain mineralization effect on the calcination of cement raw materials, and the optimal calcination temperature and aluminum rate are 1 400 ℃ and 1.1, respectively. The cement prepared by using tailings slag as iron raw material meets the relevant requirements of P·Ⅰ42.5 grade cement in GB 175—2023 Common Portland Cement. Compared with iron powder, the clinker prepared by using tailings slag as iron raw material has higher mineral composition, higher degree of reaction in the stages of crystallization nucleation and crystal growth, higher hydration heat release and hydration reaction rate, and shorter reaction time in the stage of phase boundary reaction.
徐瑞锋.有色冶炼二次尾渣制备水泥熟料的研究[J].混凝土与水泥制品,2024(7):98-102.
XU R F.Study on preparation of cement clinker from secondary tailings slag from non-ferrous smelting[J].China Concrete and Cement Products,2024(7):98-102.
李骁男,辛晓斌*,马 炎,张茂亮,李建伟
摘 要:采用不同模数(1.3、1.8、2.3、2.8、3.3)的水玻璃对黄河泥沙进行了活化处理,并制备了再生骨料透水混凝土,研究了水玻璃模数对黄河泥沙活性和再生骨料透水混凝土性能的影响。结果表明:水玻璃能明显提高黄河泥沙的活性,当水玻璃模数为2.3时,黄河泥沙的28 d活性指数达到最大,为65%;随着水玻璃模数从1.3逐渐增加至3.3,黄河泥沙中的Al3+活性率逐渐降低;与未活化黄河泥沙相比,采用活化黄河泥沙制备的再生骨料透水混凝土的抗压强度提高,耐流水侵蚀系数增大。
Abstract: Different modulus of sodium silicate(1.3, 1.8, 2.3, 2.8, 3.3) was used to activate the Yellow River sediment, and the recycled aggregate pervious concrete was prepared. The influence of sodium silicate modulus on the activity of Yellow River sediment and the performance of recycled aggregate pervious concrete was studied. The results show that sodium silicate can significantly improve the activity of Yellow River sediment. When the modulus of sodium silicate is 2.3, the 28 d activity index of Yellow River sediment reaches its maximum, which is 65%. As the modulus of sodium silicate gradually increases from 1.3 to 3.3, the activity rate of Al3+ in the Yellow River sediment gradually decreases. Compared with non activated Yellow River sediment, the compressive strength of recycled aggregate pervious concrete prepared by activated Yellow River sediment is improved, and the coefficient of resistance to water erosion is increased.
李骁男,辛晓斌,马炎,等.水玻璃活化黄河泥沙对再生骨料透水混凝土性能的影响[J].混凝土与水泥制品,2024(7):103-106.
LI X N,XIN X B,MA Y,et al.Effect of sodium silicate activated Yellow River sediment on the performance of recycled aggregate pervious concrete[J].China Concrete and Cement Products,2024(7):103-106.
摘 要:研究了分别单掺与复掺再生混凝土粉(RCP)、再生砖粉(RBP)对混凝土抗氯离子渗透性能的影响,并建立了氯离子扩散系数和电通量之间的关系式。结果表明:单掺RCP或RBP时,随着其掺量从0增至30%,试件的电通量和氯离子扩散系数均先减小后增大,说明抗氯离子渗透性能先增强后减弱,RCP和RBP的最佳掺量均为10%;复掺RCP和RBP时,随着RBP占比的增加,试件的电通量和氯离子扩散系数均先减小后增大,最佳mRBP∶mRCP为1∶1;掺再生微粉混凝土的氯离子扩散系数和电通量之间具有良好的线性关系。
Abstract: The effects of single and compound addition of recycled concrete powder(RCP) and recycled brick powder(RBP) on the chloride ion penetration resistance of concrete were studied, and the relationship between chloride ion diffusion coefficient and electrical flux was established. The results show that when RCP or RBP is added alone, as its content increases from 0 to 30%, the electrical flux and chloride ion diffusion coefficient of the specimen first decrease and then increase, indicating that the chloride ion penetration resistance first enhances and then weakens, and the optimal content of RCP and RBP is both 10%. When adding RCP and RBP together, as the proportion of RBP increases, the electrical flux and chloride ion diffusion coefficient of the specimen first decrease and then increase, and the optimal mRBP∶mRCP is 1∶1. There is a good linear relationship between the chloride ion diffusion coefficient and electrical flux of concrete with recycled micro powder.
徐秀华.再生微粉对混凝土抗氯离子渗透性能的影响[J].混凝土与水泥制品,2024(7):107-110,115.
XU X H.Effect of recycled micro powder on chloride ion penetration resistance of concrete[J].China Concrete and Cement Products,2024(7):107-110,115.