Applied Mechanics and Materials Vols. 357-360

Abstract: Foam ability and stability of foaming agent are key factors for foam concrete properties. Through researching LAS, SDS and magnesite foaming agent commercially available, the results show that adding HPMC after can reduce LAS, SDS and magnesite foam bleeding quantity and subsidence distance and has little impact on foam expansion, magnesite foam ability and stability are inferior to LAS and SDS. LAS performance is the best, when the dilution ratio is 1:50 with 0.12% HPMC after, the foam expansion is 28.1 and bleeding is 14ml, subsidence distance is 5mm, the prepared foam concrete strength is 1.14MPa and dry density is 449kg/m³.

Abstract: This paper primary researched the influence of limestone powder on the workability, the strength performance and the volume stability of self-compacting concrete (SCC). Results showed that the workability of self-compacting concrete was improved greatly by mixing proper limestone powder; besides, limestone powder could improve early age strength of concrete obviously, but had little influence on long age strength; the self-shrinkage of concrete increased as the admixture of limestone powder increased. The content of limestone should be capped at 10% and the optimum mix amount is about 7%.

Abstract: Membrane materials became the focus of the exhibition design sector in the 1970s and have developed rapidly since then. As a fabric material of excellent performance, the membrane material has been widely and innovatively used in recent years for their features of facilitating construction and transportation, energy efficiency and environmental friendliness, as well as easy combination with other materials and units. Those innovative applications not only render new functions to membrane materials, but also provide new ideas and open a new horizon to the design of the exhibition pavilions. The use of member materials will also become the mainstream of the exhibition design sector in the near future.

Abstract: As one of the measures to improve the durability of concrete, silane penetrating hydrophobic agents can preserve the properties of respiratory function of concrete and can prevent the penetration from harmful medium such as chloride ions. Because of low molecular weight of the silane penetrating hydrophobic agent such as isobutyl triethoxysilane, high volatilization rate of silane can result in waste of material in construction process. The silane oligomer was obtained by radical polymerization reaction with suitable monomers, initiators and reaction conditions. Furthermore, we verified the structure of the silane oligomer by FT-IR spectroscopy and got its molecular weight by GPC(Gel Permeation Chromatography). The silane oligomer with lower volatilization rate has excellent properties of hydrophobicity, higher penetration depth and resistance to chloride ions penetration.

Abstract: Using slag powder in concrete, not only can solve the piled slag powder problem in Baotou area, but also can save resources and energy and improve concrete performance, resulting in huge economic benefits. The results showed that slag powder can increase concrete mobility. With slag powder increasing, the C40 and C50 concrete 28d compressive strength increases and then decreases and each age shrinkage values are significantly reduced. When slag powder reach 50% of cement, concrete impermeability and anti-carbonation are excellent and 41.1yuan are saved every cubic meter concrete which lead to great social and economic benefits.

Abstract: Portland cement, crushed stone, sand and superplasticizer were used to obtain a high strength concrete with a low water to binder ratio. A reticular polypropylene fiber and a single polypropylene fiber were used to improve the strength of the high strength concrete, but the effects of the two fibers on the slump and strengths were quite different. The reasons of the differences were the surface area and the modulus of elasticity of the fibers. The results show the reticular fiber was better to used in high strength concretes.

Abstract: Portland cement, silica fume, superplasticizer and fly ash cemamsite were used to obtain a high strength lightweight aggregate concrete with lower water to binder ratio. An enhancement effect on the strength was gained by adding steel fiber. When the expansive agent added with the steel fiber a synergistic reinforcing effect on the compressive strength, tensile strength and bending strength was obtained because of more energy consumed to pull the fibers out under the different loads.

Abstract: The high strength composite ceramsite was prepared by using fly ash and waste glass as main raw materials and some admixtures such as binder and bubble-forming agent. The suitable technological condition of preparing high strength composite ceramsite was given by studying the influence of the different mix proportions and different sintering systems on the properties of ceramsite. The test results indicate that the compressive strength in cylinder of high strength composite ceramsite which was prepared under certain technological condition can reach 9.9MPa and its bulk density is 974Kg/m³ and the water absorption in one hour is 3.6%. The XRD(X Ray Diffraction) and SEM (Scanning Electron Microscope) analyses show that a large number of amorphous gel phases which affect the strength of ceramsite were produced in the process of sintering fly ash and waste glass and abundant even bubbles were formed inside of the ceramsite.

Abstract: With the rapid development of our country highway career, different pavement materials quickly appear. Open Grade Friction Course (OGFC) is a new-typed topping mixture, which has excellent permeation, anti-skidding performances. This article through the experiments of different porosity OGFC in highway using some of the effects of data, determine that the proper void rate of OGFC, Provides a theoretical basis for the use of OGFC road.

Abstract: Right evaluation of the bond behavior between corroded reinforcing bar and concrete wrapped with fiber reinforced polymers (FRPs) is a chief problem to confirm the effect of FRP confinement. the pullout tests on 96 test specimens were conducted to study the effect of Carbon FRP (CFRP) confinement on the bond behavior between corroded reinforcing bar and concrete, test variables included reinforcing bar types, concrete covers, degrees of corrosion and CFRP confinements. The test results show that CFRP confinements can make the failure mode of deformed reinforcing bar specimens change from concrete splitting to bar pullout. When the degree of corrosion is less than 5%, the ultimate bond strength of corroded specimens increases by 5%~7%; and the CFRP confinement has less contribution on the ultimate bond strength, but it is effective on slowing down the bond stress descending speed and maintaining the bond strength. When the degree of corrosion is higher than 5%, the ultimate bond strength of corroded specimens drops gradually with the increase of degree of corrosion.