Advanced Materials Research Vols. 168-170

Abstract: The mechanical properties of hybrid nylon-steel-fiber-reinforced concrete were investigated in comparison to that of the steel-fiber-reinforced concrete, at the same volume fraction (0.5%). The combining of fibers, often called hybridization is investigated in this paper for a very high strength concrete of an average compressive strength of 105 MPa. Test results showed that fibers when used in a hybrid nylon-steel fibers reinforced concrete form could result in superior composite performance compared to steel-fiber-reinforced concrete. The basic property of the hybridized material that was evaluated and analyzed extensively was the modulus of rupture (MOR) and splitting tensile while the compressive strength was only slightly decreased compared to single steel fiber reinforced concrete. There is a synergy effect in the hybrid fibers system.

Abstract: A non-corrosion, high strength, light weight material – carbon fiber reinforced polymer (CFRP) is introduced to replace steel as cable system in long-span suspension bridge for improving loading efficiency, reducing maintenance cost, enlarging the span of suspension bridge. The natural vibration characteristics of such new suspension bridge with CFRP cables are investigated by means of finite element in this paper. Two 2000m-span suspension bridges with steel cables and CFRP cables respectively are designed, analyzed, verified and compared. The analysis results provide a picture of the changes in natural vibration characteristics and the wind stability and earthquake-resistant behavior are briefly discussed if CFRP cables were applied.

Abstract: The LAS glass containing P₂O₅ has been prepared by conventional molten quenching method. The influence of heat treatment conditions on crystallization behavior, including phase transformation and microstructure, and thermal expansion coefficient (TEC) of Li₂O–Al₂O₃–SiO₂ (LAS) glass-ceramics were investigated. DSC, XRD, SEM and TEC were used to detect the microstructure and properties of glass-ceramics under the different heat-treatment conditions. The results show the virgilite crystalline separated firstly from the matrix glass when heat treatment temperature was 850 °C. As the heat treatment temperature increased from 850 °C to 1050 °C, virgilite and β-spodumene were identified as main crystal phases. The TEC of glass-ceramics ranges from 0.5×10-6 °C^-1 to 2.8×10-6 °C^-1, which is much lower than that of matrix glass.

Abstract: This paper studied the durability of Glass Fiber Reinforced Polymer (GFRP) Pole and Tower for power transmission under the UV and adverse temperature environment. The results show that both UV and adverse temperature environment influence the performance of GFRP material, with its strength significantly reduced, and its elastic modulus increased, while the Poisson's ratio changed slightly. Xenon lamp aging affects the material properties of the specimens with protective coatings more slightly than those without any protective coatings. High temperature environment affects the material properties of specimens more obviously than low temperature environment does. Therefore, when designing the GFRP Pole and Tower for power transmission exposed in UV and adverse temperature environment long-term, designers should consider the negative impacts of the external environment, and take appropriate protective treatments.

Abstract: Nine concrete columns reinforced with fine grain high steel bars under eccentric loading were tested to study the effects of experimental parameters, such as eccentricity distance, reinforcement ratio and concrete strength, on the failure pattern, the strain distribution and the lateral deformation. The experimental results indicate that the columns reinforced by fine grain high steel bars work harmonically with concrete, and the strength of fine grain steel bars could be utilized fully. Finally, the design value of 400MPa fine grain steel bar is 360MPa in column was proposed based on the experiment and the comprehensive theoretical analysis.

Abstract: An artificial neural network (ANN) is presented to predict the workability of self compacting concrete (SCC) containing slump, slump flow and V-test. A data set of a laboratory work, in which a total of 23 concretes were produced, was utilized in the ANNs study. ANN model is constructed, trained and tested using these data. The data used in the ANN model are arranged in a format of six input parameters that cover the cement, fly ash, blast furnace slag, super plasticizer, sand ratio and water/binder, three output parameters which are slump, slump flow and V-test of SCC. ANN-1, ANN-2 and ANN-3 models which containing 15 ,11 and 5 neurons in the hidden layers, respectively are found to predict workability of concrete well within the ranges of the input parameters considered. The three models are tested by comparing to the results to actual measured data. The results showed that ANN-2 is the best suitable for predicting the workability of SCC using concrete ingredients as input parameters.

Abstract: With the high proportion of building energy consumption in the total energy consumption, it is of great importance to relieve the shortage of conventional energy resources and improve the building environment by incorporating solar energy into buildings. A new type solar roof panels were designed and tested in the present paper, which perfectly achieves the integration of solar equipment with building envelope. This panel can act as the construction component for building envelope and completely removes the double-skin mode for conventional solar equipment, as well as the functional equipment for heating and cooling collecting. Corrugated colored steel roof panel was tested under various climate conditions and operation conditions. The results show that in a typical sunny day the average heat collecting efficiency is 49% and the average cooling capacity is 100W/m². In a cloudy day, the average heat collecting efficiency is 41% and the average cooling capacity is 84W/m².

Abstract: To study the mechanical properties of RPC performance and freeze-thaw resistance，through the experimental study discussed the water-cement ratio, silica fume cement ratio, steel fiber content, curing system and other factors on the mechanical properties of reactive powder concrete and anti-freezing properties. Research indicates that many factors in the RPC, the water cement ratio is the most important factor, followed by the silica fume cement ratio, finally the steel fiber content, and curing system for the growth of its early strength also have a greater role.

Abstract: Crumb rubber modified (CRM) asphalt with crumb rubber of scrap tire has higher viscosity, better flexibility, outstanding anti-fatiguing and anti-aging properties. This paper mainly investigated material design and performance evaluation of CRM asphalt SMA mixture. Brookfield Viscosity test is used to ascertain the adoption of fiber in CR-SMA. Because of resilient volume swelling of asphalt rubber mortar, gap-coarse grade must be adopted in asphalt rubber concrete to provide enough free space. This paper amends material composition and grade proportions range of adapted CR-SMA depending on the special characteristic of CRM asphalt. After confirming best grade of CR-SMA, this paper adopted Marshall Method to design Job Mix Formula (JMF) of surface layer CR-SMA13 in Beijing airport south line expressway. The best CRM asphalt content and feasible gradation middle value were obtained by Marshall Test and volume parameter calculation. During performance evaluation phase, other two SMA usually used in Beijing region is added, including SBS modified asphalt SMA, Trinidad Lake asphalt (TLA) and SBS modified asphalt SMA. By evaluations of high temperature performance, low temperature performance, moisture sensitivity and so on. The results indicate that pavement performance of CR-SMA is excellent, and have no distinct difference compared with the other two SMA.

Abstract: The interface bond between steel fibers and concrete matrix is the key of carrying capacity of steel fiber reinforced concrete(SFRC). In marine tidal fluctuation zone and splashed area, steel fibers will be rusty, and the bending toughness of SFRC was weakened. In this study, we tried to improve corrosion resistance of steel fiber and the interface bond strength by depositing zinc phosphate coating on steel fiber. These zinc phosphate steel fiber reinforced concrete(ZSFRC) have higher anti-corrosion ability. After corrosion they still have higher bending toughness than common SFRC.