Advanced Materials Research Vols. 168-170

Abstract: Styrene-Butadiene-Rubber (SBR) modified bitumen had improved properties in softening points, ductility, and aging resistance. It is due to variation of molecular weight (MW) and molecular weight distribution (MWD) of the product made during the blending between SBR and bitumen. Gel permeation chromatography (GPC) analytical results indicated interaction in polymer blends that bitumen macromolecular chain biting and chemical forces as well as intermolecular recombination formed new bitumen polymer blends.

Abstract: Multifunctional epoxy self-leveling floor coating with excellent anti-static and anti-corrosion characteristics is prepared by modified epoxy resin and curing agent which have excellent chemical resistance characteristics. Conductive materials are adding into the formula. The coating structure and the matching construction technology are designed for the anti-static and anti-corrosion self-leveling floor coating application.

Abstract: The raw materials from household garbage and industrial waste have increased its usage in the concrete and cement industries. These eco-materials have helped the environment, avoiding pollution, land filling or burning of waste and the usage of other natural resources. However, the cost of many eco-materials is still higher than that of common natural materials. It is necessary to study in detail its behavior and properties to decrease its cost and increase its performance. This research deals with Eco-cement and molten slag aggregate which main raw materials are household garbage and industrial waste. Concretes produced with Portland cement and Eco-cement were mixed with gravel, limestone, quartz and molten slag aggregates to compare its properties. The fracture energy, strength and modulus of elasticity tests were performed and discussed in this paper. The concretes produced with Eco-cement and molten slag aggregate show better results than those produced with Portland cement and natural aggregates.

Abstract: In this paper, novel filled materials EPS-blocks of cast-in-situ slabs are presented. And EPS-blocks with light weight which are inexpensive are validated to be sufficient strong as filled materials to bring an innovation for the development of cast-in-situ slabs. Based on modal analysis, it is found that the decreased weight has a greater influence to the mode of the slab than the weakened stiffness. According to harmonic response analysis, tensile stress distributions of the slab with EPS-blocks are depicted in figures and explained. Typically, orifice stress distributions are expounded and stress variations of nodes in different places are illustrated. From these studies, it is concluded that the steady state dynamic performance of the slab with EPS-blocks is good.

Abstract: The cement-based composite shielding materials was prepared using portland cement and nickel fiber. The effects of dispersive manner, contents of nickel fiber, thickness of specimens on shielding properties and conductivity were studied in a frequency range of 100 KHz~1.5 GHz. With the contents of nickel fiber by ultrasonic dispersed at 5 vol.% and specimen’s thickness of 10 mm, the conductivity is 2.58×10^-3 S•cm^-1 and maximum shielding effectiveness is 47.8 dB, average shielding effectiveness reaches about 45.9 dB for cement-based composites.

Abstract: The Mg-12Gd-2Y-Sm-0.5Zr (wt. %) alloy was prepared by casting technology and the microstructure and mechanical properties of the alloy have been investigated. It was found that the alloy was composed of a-Mg matrix, Mg5Gd phase and dispersed long-period ordered β' precipitates. With temperature increasing from 20 to 300 °C, the tensile strength increased and reached to the maximum strength at 300°C, namely 316.3 MPa. The value was superior to those of the conventional heat-resistant magnesium. The improved strain hardening and critical crack propagation stress were the key factors for experimental alloy possessed anomalous temperature dependence of tensile strength.

Abstract: In order to improve designing and well understanding the working mechanism for fiber reinforced polymer (FRP) tendon wedge anchorage system (FWAS), a theory for solving the anchorage system was presented in this paper. A designing guidelines of anchorage system was established. The theory was checked by comparing the analytical and test results of a Carbon FRP tendon anchrage system. Effect of presetting load and friction coefficient of sleeve-FRP tendon interface on anchorage performance were evaluated by the theory. The results show that, The theory was proved to be correct, it can be used to predict the carrying capacity of FWAS, and it can calculate the stress and transverse displacement of any point of the anchorage system. The presetting load and friction coefficient of sleeve-FRP tendon interface have great impact to anchorage performance.

Abstract: Coating protection becomes the primary and available method for the protection of marine concrete. Aliphatic polyurea is a new genre of polyurea. In the present study, the frost resistance property and adhesion property of 2 different aliphatic polyurea coated concretes under salt fog exposure were studied for the first time. The surface morphology and molecular structure of the coating under the salt fog exposure were investigated through SEM and FTIR. The investigations on the influence of the salt fog exposure to the PAE-t-HDI prepolymer-D2000H65 aliphatic polyurea (T3) coated concrete and T3 finishing coat/ MDI emulsion primer aliphatic polyurea (TM) coated concrete reported that after 300 days salt fog exposure, the relative dynamic elastic modulus of T3 and TM coated concrete were more than 85%, and their wet adhesion were 1.0 N/mm and 2.5N/mm respectively. SEM and FTIR researches showed that no obvious changes were observed in the surface morphology and structure of the coating after 200 days salt fog exposure. The results indicate that aliphatic polyurea coated concretes have favorable salt fog resistance, and are suitable for applying in marine concrete structures.

Abstract: The combination of warm compaction and die wall lubrication, called die wall lubricated warm compaction was used to make Fe-Ni-Cu-Mo-C powder metallurgy material. Results showed that the green density could be 7.38 g•cm-3 under the pressure of 700MPa at the temperature of 120°C. The sintered density could be 7.34 g•cm-3 and dimension change was 0.19% when sintered at 1200°C for 50 minutes. Both green density and spring back effect gradually increased as the compacting pressure rose. The relation between compacting pressure and green density could be described by Huang Pei-yun double logarithm equation. Different forming conditions effecting green density in turn from big to small were compacting pressure, lubrication, compacting temperature, mixing method and compacting speed.

Abstract: The cement-based composite shielding materials filled with carbon materials such as ordinary carbon materials (graphite, coke and carbon black), carbon fiber and nano-carbon materials (carbon nano-tube and nano-carbon black) were prepared. The relationship of conductivity and shielding effectiveness in a frequency range of 100 KHz~1.5 GHz was studied. The electric properties of cement-based composites filled with carbon fiber is better than other carbon materials. With the contents of carbon fiber of 5.vol%, the average shielding effectiveness is about 37 dB and the maximum shielding effectiveness reaches 40 dB.