نوع مقاله : مقاله پژوهشی
نویسندگان
گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه بجنورد، بجنورد، خراسان شمالی، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Incorporation of crumb rubber (CR) among ballast aggregate is characterized as an advantageous way to considerably lessen the degradation rate of granular particles. Meanwhile, there is an uncertainty about the proper drainage performance of mixture whenever the ballast aggregate is further degraded. The present study evaluates the drainage capability of degraded ballast aggregate in which disparate percentages and sizes of discarded granulated rubber particles are incorporated. To provide degraded aggregate, the impact loading test under controlled condition is implemented on fresh railway ballast. Afterwards, the large-scale constant head permeability test is carried out on prepared mixtures of degraded aggregate and CR particles. The results confirm that the effect of CR size on drainage potential of degraded ballast combined with discarded CR particles is more than the influence of CR percentage. Also, the nonlinear trend line observed between the applied hydraulic gradient and the water flow velocity approaches to the conventional linear trend line represented by Darcy’s law whenever the smaller-sized CR particles are incorporated into the most degraded ballast aggregate. As expected, higher level of degradation of aggregate decreases the hydraulic conductivity of ballast specimen, meanwhile the permeability is yet considerably more than the acceptable limit even for specimens subjected to significant level of degradation combined with the smaller-sized crumb rubber particles.
کلیدواژهها [English]
)