Advanced Materials Research Vols. 753-755

Abstract: An Experimental testing program was undertaken using full-scale specimen of seven reinforced concrete columns, one of which was employed as control without corrosion, and the other six of which were corroded in different degree. The test results indicate that with the increase of the corrosion level, the failure mode change from flexural-shear failure ,due to crushing of core concrete, to flexural-shear failure, due to fracture of stirrup. Although corrosion of stirrup do not influence distinctly on the ultimate strength of the columns, the ultimate drift and plastic rotation capacities greatly decrease with increasing the corrosion level. Compared with the test results, a calculation value can be more accurately acquired from the proposed method predicting the shear strength, through which both the minimum residual area and average corrosion weigh loss of stirrup are both considered.

Abstract: Structure of the impervious material GCL bentonite was destroied by the action of repeated freezing and thawing in irrigated areas in northren part of China, and the anti-seepage performance of the GCL was weakened. Freezing point is an index to identify whether the soil mass was in frosting state, it is very important for us to research infiltration law. This paper researches the relationships among the freezing point, density and water content. Using these relatively easily provide reference for the application of GCL bentonite in the future in the alpine region. The results show that the freezing point of GCL bentonite increases when the water content and density of GCL bentonite is increasing, and the freezing point of GCL bentonite with lower water content changes more distinctly with the density.

Abstract: Steel slag has been using as a substitution of natural aggregate, such as basalt and limestone, in road construction. But the huge asphalt absorption of slag has been a main obstacle to hinder the utilization of slag. But the detailed study in this area is still less. This paper investigated the asphalt absorption characteristic of steel slag. The results suggest that: the value of asphalt absorption of steel slag (AAOS, the weight of asphalt absorbed by per 100g steel slag) is much higher than the ones of limestone or basalt; AAOS increase slowly with the prolongation of storage time or the increase of storage temperature; the increase of viscosity causes a drastic reduction of asphalt absorption. The results also reveal that with the increase of asphalt content the AAOS value firstly increases and then decreases.

Abstract: SBS is a styrene - butadiene - styrene block copolymer, the addition of SBS of high and low temperature performance and road can be very good to improve the performance of asphalt. This paper studied the performance of the modified asphalt on the content of modifier.

Abstract: Based on experiment of a two-bay two-story reinforced concrete frame with construction joint under low-reversed cyclic loading, hysteretic performance, displacement ductility, bearing capacity degeneration, rigidity degeneration, energy dissipation and displacement restoring capacity are studied systematically. The studies show that the frame with construction joint has not better seismic performance than the monolithic cast frame.

Abstract: Given the fire accidents in recent years, we should placed great importance on the fireproof materials of buildings except arson. This paper summarized the research status methods and distinguishing features of fireproof materials in China which would make progress to our research on fireproof materials.

Abstract: The fitting models of dynamic modulus of asphalt mixtures were studied in this paper. UTM dynamic modulus tests were adopted to determine the dynamic modulus of two asphalt (A, B) mixtures. Then, the WLF equation and Arrhenius formula, based on the time-temperature equivalence principle, were used to get the shift factors and master curves of asphalt mixtures. Combined with Sigmoidal model and CAM model, it was founded that the Arrhenius formula was more suitable to get the master curves of asphalt mixtures. What is more, the CAM model was more suitable to fit master curves of both asphalt mixtures.

Abstract: Currently, rejuvenator seal which is one of the preventive maintenance methods is more widely used due to its economic benefits and convenience. This paper described the chemical and rheological evaluation of the aged styrene butadiene styrene modified asphalt (ASMA) treated by two rejuvenator sealer materials (RSMs). First the ASMA was rejuvenated by mixing with the RSMs. Then the ASMA and two rejuvenated binders were re-aged by 10h PAV test. At last, the new binder, ASMA, rejuvenated ASMAs, re-aged binders were tested by Dynamic shear rheometer (DSR) and Fourier Transform Infrared Spectroscopy (FTIR). The results showed that the first aging of the new binder had a significant decrease of the low temperature performance and slight improvement of the high temperature performance. In addition, the high temperature performance increased obviously after 10h PAV test. Two RSMs could significantly soften the aged binder due to increase of maltene content existing in the RSMs, and the rejuvenated binder exhibited a better low performance after the 10h PAV test. However they cannot restore the low temperature completely because that RSMs cannot remedy the degradation of SBS modifier and remove the carbonyl produced in the aging progress.

Abstract: The importance of aeroelastic interaction in the design of bridge decks is nowadays apparent. Key role played by the Scruton number in wind engineering applications is discussed in this paper, the windtunnel tests carried out to estimate the aeroelastic parameters of this model are presented. We also demonstrates by means of numerical integrations the validity of the approximate solution and identification procedure, Finally, the results of the previously mentioned numerical identification procedure are presented.

Abstract: Freeze-thaw disaster is an outstanding problem of geotechnical engineering in cold regions. The temperature field of tunnel surrounding rock in Qilian mountain Osaka hill was calculated according to the transient heat conduction differential equation, meanwhile the freezing conditions of tunnel surrounding rock was forecasted and analyzed after its opening. The study shows that the freeze-thaw environment has a great influence on the temperature distribution of surrounding rock. The tunnel wall and near the mouth of the cave area are more susceptible to the influence of the open ground temperature and air convection, thus the temperature changes violently , but the temperature distribution in surrounding rock tends to be dynamic stable equilibrium as time goes on. The research results can provide a reference for tunnel design and construction in cold regions.