张耀宇,王文明,蔡炎皓,等.外加剂对沙漠砂混凝土3D打印性能的影响[J].混凝土与水泥制品,2022(9):1-6. ZHANG Y Y,WANG W M,CAI Y H,et al.Effect of Admixture on 3D Printing Performance of Desert Sand Concrete[J].China Concrete and Cement Products,2022(9):1-6.

摘   要：采用异戊烯醇聚氧乙烯醚（TPEG）作为减水剂合成大单体，通过引发剂进行聚合反应合成石膏基材用新型高性能聚羧酸减水剂母液，将合成的减水剂母液通过离心喷雾干燥技术制备成粉末（PC-GY）。设计正交试验研究了链转移剂用量、酸醚摩尔比、还原剂摩尔比、引发剂用量对石膏净浆流动度的影响，并确定了最优配合比。通过单因素变量试验研究了不同种类聚醚单体、中和固碱量对减水剂减水性能的影响，并通过红外光谱（IR）分析了聚羧酸分子结构。结果表明：合成的PC-GY性能较优，在不同种类石膏中均表现出良好的适应性，并成功应用于石膏基自流平砂浆。 Abstract: Isoprene polyoxyethylene ether(TPEG) was used as a synthesize macromonomers of water reducer, and the polymerization reaction was occured through the action of an initiator to synthesize the mother liquor of a new high performance polycarboxylate water reducer for gypsum substrates, and the powder(PC-GY) was prepared with synthesized water reducer mother liquor by centrifugal spray drying technique. Orthogonal experiments were designed to study the effects of chain transfer agent dosage, acid ether molar ratio, reducing agent molar ratio and initiator dosage on the fluidity of gypsum slurry, and the optimal mixing ratio was determined. The effects of different kinds of polyether monomers and the amount of neutralized solid base on the properties of the superplasticizer were studied by single factor variable tests, and the molecular structure of polycarboxylate was analyzed by infrared spectroscopy(IR). The results show that the synthesized PC-GY has better performance and shows good adaptability in different kinds of gypsum. PC-GY is successfully applied to prepare gypsum based self-leveling mortar.

逄鲁峰,孙立刚,陈炳江,等.石膏产品用新型高性能聚羧酸减水剂的制备与性能研究[J].混凝土与水泥制品,2022(9):7 -11,28. PANG L F,SUN L G,CHEN B J,et al.Preparation and Properties of a New Type of High Performance Polycarboxylate Superplasticizer for Gypsum Products[J].China Concrete and Cement Products,2022(9):7 -11,28.

摘   要：通过改变环氧基结构胶A、B组分之间的比例及混凝土受压试件的裂缝宽度，研究了不同A、B组分比例与裂缝宽度对开裂混凝土试件抗压强度修复性能的影响。结果表明：环氧基结构胶A、B组分的最优质量比为A∶B=3∶1，此时环氧基结构胶对开裂混凝土的抗压强度的修复效果最好；裂缝宽度基本不影响环氧基结构胶对开裂混凝土抗压强度的修复效果；通过ABAQUS数值建模分析得到修复后混凝土试件内部的应力分布与实际抗压强度一致，说明环氧基结构胶可以对开裂混凝土进行有效修复、补强。 Abstract: By changing the ratio between components A and B of epoxy-based structural adhesives and the crack width of concrete compressive specimens, the effects of the different proportions of components A and B and the width of cracks on the compressive strength repair performance of cracked concrete specimens were studied. The results show that the optimal mass ratio of components A and B of epoxy-based structural adhesive is A∶B=3∶1, at this time, epoxy-based structural adhesive has the best repair effect on the compressive strength of cracked concrete. The crack width basically does not affect the repair effect of epoxy-based structural adhesive on the compressive strength of cracked concrete. Through the ABAQUS numerical analysis, the stress distribution inside the concrete specimens after repair is consistent with the actual compressive strength, indicating that the epoxy-based structural adhesive can effectively repair and strengthen cracked concrete.

汪雷,卫成凤,杜健民,等.环氧基结构胶对开裂混凝土抗压强度修复性能研究[J].混凝土与水泥制品,2022(9):12-15. WANG L,WEI C F,DU J M,et al.Research on the Repair Performance of Epoxy-based Structural Adhesive on the Compressive Strength of Cracked Concrete[J].China Concrete and Cement Products,2022(9):12-15.

摘   要：研究了不同质量比的石墨烯-羧基化碳纳米管对水泥基复合材料力学性能的影响。试验结果表明：掺入石墨烯（G）、羧基化碳纳米管（CNT）后，试件的抗压、抗折强度均出现了明显的提高；相较于单掺G和CNT，复掺0.05%的G和0.10%的CNT（G5C10）时，试件的抗压、抗折强度提高效果更显著，28 d的抗压、抗折强度达62.91 MPa和8.52 MPa，相较于对比组分别提高了37.5%和25.8%。MIP和SEM结果表明，G5C10为最佳掺入比例，此时试件的有害孔大幅减少，在微孔隙裂缝等薄弱区域形成致密化结构。 Abstract: The effects of different mass ratio of graphene-carboxylated carbon nanotubes on the mechanical properties of cement-based composites were studied. The test results show that the compressive strength and flexural strength of specimen increase obviously with the addition of graphene(G) carboxylated carbon nanotubes(CNT) composites. Compared with the specimen incorporated G or CNT, adding 0.10% CNT and 0.05% G is beneficial to improve its mechanical properties significantly, 28 d compressive strength and flexural strength reaching 62.91 MPa and 8.52 MPa, increasing by 37.5% and 25.8% compared with the control group. The MIP and SEM results show that G5C10 group is the best ratio, at this time, the harmful pores of cement mortar are greatly reduced, and then a densification structure in the weak areas such as micro-pores and cracks can be formed.

王小凡,朱华.石墨烯-羧基化碳纳米管水泥基复合材料力学性能研究[J].混凝土与水泥制品,2022(9):16-19. WANG X F,ZHU H.Mechanical Properties of Graphene-carboxylated Carbon Nanotubes Cement-based Composites[J].China Concrete and Cement Products,2022(9):16-19.

摘   要：为较准确预测混凝土28 d的抗压强度，以水泥、粉煤灰、砂、碎石和水5种原材料的单位用量作为输入，混凝土28 d抗压强度作为输出，构建了一个拥有249组样本的数据库。运用决策树、支持向量机、高斯过程回归、集成学习、神经网络5种机器学习算法进行超参数优化，构建了混凝土28 d抗压强度预测模型，并对其精度进行了评估。对比5种机器学习算法结果可知：高斯过程回归模型是预测混凝土28 d抗压强度的最优预测模型；基于构建的高斯过程回归模型对无岳高速WYTJ-07标段隧道工程自制的5种花岗岩混凝土28 d抗压强度进行了预测，预测值的最大相对误差为8.95%，证明该模型预测精度良好，可靠性高。 Abstract: In order to accurately predict the 28 d compressive strength of concrete, a database with 249 groups of samples was constructed with the unit dosage of cement, fly ash, sand, gravel and water as the input and the 28 d compressive strength of concrete as the output. 5 machine learning algorithms, namely decision tree, support vector machine, Gaussian process regression, ensemble learning and neural network were used to optimize the parameters. The prediction models of 28 d compressive strength of concrete were constructed and their accuracies were evaluated. Comparing the results of the 5 machine learning algorithms show that the Gaussian process regression model is the optimal model for predicting 28 d compressive strength of concrete. Based on the constructed Gaussian process regression model, the 28 d compressive strength of five kinds of granite concrete prepared by the project department of WYTJ-07 section of Wuyue Expressway tunnel project is predicted. The maximum relative error between the predicted and actual values is 8.95 %, proving that the constructed model has good prediction accuracy and high reliability.

刘德胜.基于机器学习算法的混凝土28 d抗压强度预测[J].混凝土与水泥制品,2022(9):20-24. LIU D S.The Prediction of 28 d Compressive Strength of Concrete Based on Machine Learning Algorithms[J].China Concrete and Cement Products,2022(9):20-24.

摘   要：研究了凝胶型和颗粒型纳米SiO2的分散性和掺量对混凝土的抗压强度、抗碳化性能和抗氯离子渗透性能的影响。结果表明：同条件下，凝胶型比颗粒型纳米SiO2的分散性好；经过超声处理的比未超声处理的纳米SiO2的分散性要好，可以有效改善混凝土的后期抗压强度、抗碳化性能和抗氯离子渗透性能；在一定范围内，纳米SiO2的掺量越大，对混凝土的性能改善效果越明显。 Abstract: The effects of the dispersibility and dosage of gel-type and particle-type nano-SiO2 on the compressive strength, carbonation resistance and chloride ion penetration resistance of concrete were studied. The results show that under the same conditions, the dispersibility of the gel-type nano-SiO2 is better than that of the particle-type nano-SiO2. The dispersibility of the nano-SiO2 dispersed by ultrasonic is better than that of the non-ultrasonic dispersed nano-SiO2, which can effectively improve the later compressive strength, anti-carbonization performance and the resistance to chloride ion penetration of concrete. within a certain range, the larger the content of nano-SiO2, the more obvious the effect of improving the performance of concrete.

陈际洲,乔晓立,唐兴滨,等.纳米SiO2的分散性和掺量对混凝土性能的影响[J].混凝土与水泥制品,2022(9):25-28. CHEN J Z,QIAO X L,TANG X B,et al.Influence of Dispersibility and Content of Nano-SiO2 on Concrete Properties[J].China Concrete and Cement Products,2022(9):25-28.