Advanced Materials Research Vols. 1065-1069

Abstract: Investigation was launched on cracking resistance of concrete with incorporation of different fibres in terms of mechanical performances, shrinkage and cracking sensitivity with employment of plate and temperature and stress test machine. Results indicated that little difference was observed on strength, Young’s elastic modulus and autogenous volume deformity among concrete made from different fibres, and incorporation of PVA fibres elevated the ultimate tension by 8 per cent in comparison with the referenced concrete while PP fiber showed no obvious effect. Cracking resistance of concrete was improved from Grade V to Grade I with incorporation of PVA and PP fibres through plate method and concrete made with PVA was rated better in cracking resistance because of lower cracking temperature according to RILEM TC119. Based on investigation launched above, PVA fibre was finally selected and so far the dam was in good shape and runs well.

Abstract: On the analysis of main factors influencing on carbonation of concrete is a stochastic model and criterion of carbonation life prediction of bridge protection layer of concrete carbonation depth. Detection results with long age of railway bridges, the minimum requirements for concrete bridge in northern area of the design strength and thickness of protection layer.

Abstract: SBS modified asphalt has good abilities to resisting pressure of high or low temperature and rutting in areas where changes of temperature is large. In our country,It is one of the important engineering materials which can solve the problem of heavy traffic on asphalt pavement and rutting in long and steep roads.In order to deeply understand the changes of rheological properties during the Thermal aging reaction of SBS modified asphalt,under different temperature conditions.regarded 90 # asphalt with CNOOC as lateral reference standard, Systematic study has been applied on the rheological properties of SBS modified asphalt and 90 # asphalt at different temperatures by using methods of DSR.The results showed that:during 28°C~34°C,with the rising of Temperature,performance of Resistance to fatigue cracking of the original modified asphalt and the original 90 # asphalt has became more and more strong.At the same temperature,the original modified asphalt’s performance of Resistance to fatigue cracking is stronger than the original 90 # asphalt’s.Long and short-term aging reactions weaken the performance of resistance to fatigue cracking of SBS modified asphalt and 90 # asphalt, and the effects of long-term weakening is more obvious.during 52°C~76°C,the anti-rutting performance of SBS modified asphalts and the 90 # original asphalts became more an more bad with the rising of Temperature.

Abstract: The bonded joints between CFRP and high strength concrete subjected to different wet-dry cycles and sustained loads were studied with double-lab shear tests. The results indicate that with the increase of cycles, the ultimate bond load rises at early stage, however decreases generally. Sustained loads significantly affect failure mode of specimens, and make the destruction more sudden.

Abstract: In order to analyze the effect of mineral powder on the high-temperature rut resistance and fatigue cracking resistance performance of unaged,short-term and long-term aged asphalt mortar, Dynamic Shear Rheometer (DSR) was used to study different powder/bitumen ratio of asphalt mortar. The results indicate that increasing mineral powder content can improve high-temperature rut resistance performance of asphalt mortar, but decrease its fatigue cracking resistance performance. As the experiment temperature rises, high-temperature rut resistance performance of different asphalt mortar will decrease, on the contrary, rising fatigue cracking resistance performance.

Abstract: The experiment study on the effect on the waste rubber concrete carbonization resistance performance from using three different doses of rubber which is 5%, 10%, 15% and three different rubber particle size which is 2-4 mm, 30-40 mesh, 60-80 mesh .The conclusion is that the concrete adding rubber particles had an adverse effect on early carbonation resistance of concrete, but late can make concrete carbonation resistance ability raise; Different rubber particle size and different influence on concrete carbonation resistance ability, 10% rubber content effect is the best, and the smaller the particle size of rubber particle concrete carbonation resistance ability of the better the results.

Abstract: Experimental studies and regression analysis of experimental data show that when using HL hardness tester (under conditions of C-type/D-type impact device) to measure the tensile strength of steels from existing steel structures, the relation curves between Leeb hardness and tensile strength of steel can be achieved. It may provide a non-destructive (NDT) method for testing tensile strength of steel.

Abstract: Common concrete, lightweight aggregate concrete and self-compacting concrete with strength grade C50 were tested under freeze-thaw actions. Experimental results show that the Light weight aggregate concrete has the best freeze-thaw resistance. Furthermore, the relative dynamic elastic modulus is used to quantitatively analyze the interior damage of concrete materials subjected to freeze-thaw actions, and the freeze-thaw damage evolution equations were established by using quadratic functions, and the computational damage values agree well with the experimental results.

Abstract: Adding polymer into cement concrete is used to increase the interlayer bonding performance. The impact of polymer on the interlayer bonding performance was studied by shear strength and tensile strength test. The mix design of the interface agent was optimized through the tensile bending tests of different fiber and polymer dosage. The impact of casting methods and interface agent mix was studied through tests. The test results show that: adding organic fiber and polymer into cement concrete could significantly increase the interlayer bond strength. The interface agent of SBR (styrene-butadiene rubber) latex modified cement paste has better tensile bonding properties. When the ratio of cement to DB-1 latex is 3:2, it will effectively increase the interlayer bonding performance of cement concrete.

Abstract: Slag glass-ceramics were successfully prepared by cold pressing sintering method in different atmospheres from metallurgical solid wastes. The evolution of crystal microstructure and crystalline phase transition of slag glass-ceramics was investigated by thermo-gravimetric analysis (TG-DTA), X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) coupled with Energy Dispersive X-ray spectrometer (EDX). The results indicate that the Na₂O composition plays the role of decreasing the crystallization temperature to some extent. Iron oxides make the glass frits have a high driving force to crystallize. This oxidation of ferrum will postpone the process of densification and deteriorate the mechanical properties of product. On the other hand, the slag glass-ceramic products can obtain novel mechanical performance when the samples were sintered under nitrogen atmosphere.