This paper mainly studies on the biaxial tensile strength and its calculative formula of a special made concrete. According to the Hill theory and the uniaxial tensile experiment results, the expression of the concret...This paper mainly studies on the biaxial tensile strength and its calculative formula of a special made concrete. According to the Hill theory and the uniaxial tensile experiment results, the expression of the concrete biaxial tensile strength is deduced, which is then combined with experiment data and checked. The result shows： the biaxial tensile strength of this kind of concrete is about 15%-30% lower than its uniaxial tensile strength, and the calculative value is basically consistent with the experiment value, with less than 11% difference. This kind of biaxial tension weakening effect is very important to the structure designs of concrete road. The author suggests further research.展开更多
Increasing traffic volumes and loads as well as public expectation for a long-lasting transportation infrastructure have necessitated designing perpetual pavements. The KDOT （Kansas Department of Transportation） con...Increasing traffic volumes and loads as well as public expectation for a long-lasting transportation infrastructure have necessitated designing perpetual pavements. The KDOT （Kansas Department of Transportation） conducted a field trial to investigate the suitability of perpetual pavement concept for Kansas highway pavements. The experiment involved construction of four thick pavement structures. To verify the approach of designing perpetual pavements on the basis of an endurance strain limit, the pavements were instrumented with gauges for measuring tensile strains at the bottom of asphalt base layers at various speeds. Pavements were also instrumented with pressure cells to measure stress on the top of subgrade. Pavement response measurements under known vehicle load were performed in August 2006. FWD （Falling-weight deflectometer） was also used to collect deflection data at 15 m intervals on the same date. FWD first-sensor （center） deflections were normalized and corrected to 20 ℃ temperature based on measured mid-depth pavement temperature. The result shows that strain and stress measurements show significant amount of variations. Measurements in the thickest section are the most consistent. The higher the traffic speed, the lower the strains and stresses. The difference between strains and stresses at 30 kmhar and 65 km/hr is higher than the difference between 65 km/hr and 95 kin/hr. This shows the effect of speed on stresses and strains decreases as the speed increases. Softer binder in the asphalt base layer results in lower strains, which confirms that softer binder results in higher fatigue life.展开更多
文摘This paper mainly studies on the biaxial tensile strength and its calculative formula of a special made concrete. According to the Hill theory and the uniaxial tensile experiment results, the expression of the concrete biaxial tensile strength is deduced, which is then combined with experiment data and checked. The result shows： the biaxial tensile strength of this kind of concrete is about 15%-30% lower than its uniaxial tensile strength, and the calculative value is basically consistent with the experiment value, with less than 11% difference. This kind of biaxial tension weakening effect is very important to the structure designs of concrete road. The author suggests further research.
文摘Increasing traffic volumes and loads as well as public expectation for a long-lasting transportation infrastructure have necessitated designing perpetual pavements. The KDOT （Kansas Department of Transportation） conducted a field trial to investigate the suitability of perpetual pavement concept for Kansas highway pavements. The experiment involved construction of four thick pavement structures. To verify the approach of designing perpetual pavements on the basis of an endurance strain limit, the pavements were instrumented with gauges for measuring tensile strains at the bottom of asphalt base layers at various speeds. Pavements were also instrumented with pressure cells to measure stress on the top of subgrade. Pavement response measurements under known vehicle load were performed in August 2006. FWD （Falling-weight deflectometer） was also used to collect deflection data at 15 m intervals on the same date. FWD first-sensor （center） deflections were normalized and corrected to 20 ℃ temperature based on measured mid-depth pavement temperature. The result shows that strain and stress measurements show significant amount of variations. Measurements in the thickest section are the most consistent. The higher the traffic speed, the lower the strains and stresses. The difference between strains and stresses at 30 kmhar and 65 km/hr is higher than the difference between 65 km/hr and 95 kin/hr. This shows the effect of speed on stresses and strains decreases as the speed increases. Softer binder in the asphalt base layer results in lower strains, which confirms that softer binder results in higher fatigue life.
