Advanced Materials Research Vols. 194-196

Abstract: In this paper, an innovative research on mechanism of a non-shrinkage and high early strength composited cements-based grouting material is presented. A blend cements system of ordinary Portland cement (OPC), calcium aluminate cement (CAC) and calcium sulfate (CS) were used in the innovative grouting material. Through the systemic studies on the influence of the constituents on properties of the grouts and microstructural study by Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD), experimental results show that the development of the compressive strength and expansion ratio in hydrated cementitious grouts resulted from ettringite formation and quantity of ettringite crystals in the cementitious grouts.

Abstract: In this paper, mechanical performances of 480 specimens are tested and influences of basalt fiber ratio, slenderness, soakage material are studied. Results indicate that mechanical properties of BFRC are better than plain concrete. It can be found that the best mechanical performance may be get when the basalt fiber soaked by water-solubility material and its ratio at 8.4 to 14 kg per square meter as well as slenderness at 600 to 800.

Abstract: An experimental system of high-temperature split Hopkinson pressure bar (SHPB) was developed by combination of the split Hopkinson pressure bar (SHPB) and microwave heating system, then tests of concrete whose temperature changed from room temperature to 650°С and impact velocity from 5m/s to 12m/s were completed. Based on the test results, the dynamic strength of concrete increases with increasing impact velocity whether with high temperature or room temperature, meanwhile the dynamic strength of concrete with high temperature has the strain rate effect, but the effect keeps decreasing with temperature increasing, even at temperature above 500°С , compressive strength will not have strain rate sensitive effect any longer when strain rate surpasses a certain value. In the meantime, the strain rate hardening effect is coupled with high temperature weakening effect, but the latter has greater influence.

Abstract: The application of planting bars technology in engineering strengthening and rebuilding is extensive. Contrary to organic material, inorganic material has advantages in high temperature resistance and long-term durability. Based on pull-out test of different diametrical rebars(12,14,16,20,22) with different anchorage length(10d,15d,20d) in concrete foundation of different strength(C20,C25,C30,C40).Factors affecting the ultimate bearing capacity of rebars are deduced. Fatherly the load-displacement curve is obtained. The result provides the basis for engineering application design. Its characteristics in early strength, adhesive force to concrete can satisfy the need of the building to the planting rebars with inorganic material and the loading force. Therefore it can be used as a substituting material for anchoring adhesive.

Abstract: Smart concrete is the product of modern building materials combining with modern technology and the advanced stage of the traditional concrete development. But the smart concrete material is currently in the research and laboratory stage and is far away from large-scale practical application stage. The history and developing status of the smart concrete were reviewed. The definition and classification of the smart concrete were discussed in detail. The developing trend and prospects of the smart concrete were analyzed and some problems were proposed.

Abstract: A modified polycarboxylate superplasticizer was synthesized by copolymerization of polyethylene glycol monomethyl ether methacrylate (MPEG-MA), β–Cyclodextrins grafted maleic anhydride (MAH-β-CD), methacrylic acid (MAA) and methallyl sulfonic acid (MAS). The excellent superplasticizer was obtained at the molar ratio of n(MAH-β-CD) : n(MAS) : n(MAA) : n(MPEG-MA) was 0.05:0.1:3:1 using ammonium persulfate (APS) as initiator at 90°C for 5 h. The applied results show that the product had many advantages, such as lower dosage, longer setting time, better flow-keeping ability and better compatibility with different cement. Meanwhile, the structure and relative molecular weight were characterized by FTIR and GPC respectively.

Abstract: Railway wind-break wall is widely used, which is of significant importance to prevent running vehicles from suffering the risk of overturning. In the paper, application of railway wind-break wall and specific details of its structure are introduced. Wind tunnel test and CFD simulation are widely used in the researches on the performance of railway wind-break wall and some important results are summarized. Based on the review, developments of railway wind-break wall in the future are provided.

Abstract: longitudinal and transverse impact strength tests of plybamboo form with different moisture content were performed. Regression Equations of longitudinal and transverse impact strength of plybamboo form were constructed through numerical fitting. The results show that both longitudinal impact strength and transverse impact strength increase with the increasing of the moisture content of the plybamboo form. The average value of longitudinal impact strength increases or decreases 0.20kJ/m² when the value of moisture content increases or decreases 1%. The average value of transverse impact strength increases or decreases 0.12kJ/m² when the value of moisture content increases or decreases 1%. The results of variance analysis and significance test of the two linear regression equations show that both the regression equations achieve very significant level.

Abstract: As is known to us, producing tradition wall materials will consume lots of energy and spoil the environment. Therefore, new-type wall has aroused great concern among people in construction, which is green, insulating and energy-saving and so on. External insulation, promoted as an energy-saving technology in building insulation, has three more mature technologies. This paper also introduces polyurethane insulation material, as the third generation of energy-saving wall materials, has a very good application prospect in scientific research. Finally, in the last of the paper, relative countermeasures and suggestions are made to improve the status and development of new-type wall materials, for instance: we should make the most of industrial waste, make deep research in new composite wall systems and wall materials; take some effective measures to accelerate the application of new wall materials and so on.

Abstract: This paper considers the application of Super Absorbent Polymer(SAP) in expansive concrete with different cementitious materials. The macroscopic properties of concrete have been researched through testing restricted expansive rate and mechanic properties of concrete after adding SAP. The test result shows that SAP can promote cement hydration while keeping concrete a good volume stability. By means of scanning election microscopy (SEM) and spectroscopy , the submicroscopic structure of SAP concrete is analyzed in order to explain its macro-properties.