公务人员
Journal of Civil Engineering and Architecture 12 (2018) 97-105
doi: 10.17265/1934-7359/2018.02.003
续范亭
Study on Test Methods for Mechanical Properties of Semi-rigid Ba Cores of In-rvice Pavements
Song Bo1, 2, Zhang Jin-xi1, Xue Zhong-jun2, Zhou Xu-li2 and Zhang Tao2
测量专业
1. School of Metropolitan Transportation, Beijing University of Technology, Beijing 100124, China婚纱相册
2. Beijing Board Engineering Quality Supervision Station, Beijing 100076, China
Abstract: Compressive strength and compressive resilience modulus are two important parameters to measure the mechanical properties of mi-rigid ba. The test methods of mi-rigid ba cores are different from tho of the laboratory samples in terms of sample acquisition, sample lection and humidity requirements. Core-drilling location, size of core sample, smoothness and humidity conditions were analyzed. The test methods of compressive strength and compressive resilience modulus were propod. The rearch results show that compressive strength of lime fly-ash stabilized gravels ba has a tendency of increasing during a long period. The compressive resilience modulus increas significantly with compressive strength of mi-rigid ba. The compressive resilience modulus general自己开车
ly is 3-4 times than the recommended range of asphalt pavement design specifications. The fluctuation range of compressive resilience modulus is obviously higher than the compressive strength. The compressive resilience modulus is more nsitive to the construction variability. The overall trend between the compressive resilience modulus and the back-calculation modulus is consistent. FWD (falling weight deflectometer) back-calculation modulus can reflect the stiffness and bearing capacity of asphalt pavement.
Ker words: Road engineering, mi-rigid ba cores, compressive strength, compressive resilience modulus, test methods.
勇于探索1. Introduction
Asphalt pavement is one of the main forms of high-grade pavement. Until 2015, the mileage of asphalt pavement was more than 790,000 km in China [1]. The vast majority of asphalt pavement is compod of mi-rigid ba, which materials are cement stabilized macadam or lime-fly ash stabilized macadam. With the rapid development of the highway transport and the increasing traffic load, some mi-rigid asphalt pavements had appeared different degrees of damages, most of which are due to the lack of strength and inconsistent construction of the mi-rigid ba [2]. Compr
essive strength and compressive resilience modulus are important parameters to measure the mechanical properties of the mi-rigid ba, which directly affect the rvice quality and life of asphalt pavements [3-5].
Corresponding author: Song Bo, doctoral candidate, rearch fields: materials and structures of road engineering.
South Africa adopted the concept of effective modulus for mi-rigid ba and applied the effective modulus to the two-stage pavement design method [6]. In the first stage, the effective modulus of the mi-rigid ba is 500-3,000 MPa. In the cond stage, the compressive resilience modulus of mi-rigid ba decays to 70-500 MPa after fatigue cracking. Shrinkage performance can be improved by modifying the graduations of ba materials rather than reducing the cement content which will lead to strength loss [7]. The mi-rigid ba modulus in asphalt pavement with no rious dia is greater than 2,000 MPa, The mi-rigid ba modulus in asphalt pavement with rious dia is less than 2,000 MPa [8]. A test method of mi-rigid materials bad on measurement of strain in the middle ction of the specimen can improve the reliability of uniaxial compressive resilience modulus and reduce the influence of friction constraints at both ends [9]. The existing
specifications provide test methods of compressive
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