摘要:

To understand what actually happens in the pavement as aircraft wheels pass by, pavement deflections and strains were plotted against time using field test data collected at Denver International Airport. Shapes of the response–versus–time curves were analyzed in detail, and the locations of the maximum responses are shown graphically.According to the analysis, maximum deflections occur between the dual wheels, whereas maximum strains occur beneath one of the wheels. The plots also show clear reversals in the longitudinal strain–versus–time curves. These strain reversals were carefully investigated and some interesting results were obtained. A method to compute the deflection–based load transfer efficiencies was developed. The computation further showed that the load transfer efficiency for dummy joints is direction dependent, and that the load transfer efficiency decreases significantly during the first year the pavement is in service.

ISSN:1029-8436    

DOI:10.1080/10298439908901693

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

This paper describes the development of a novel method of measuring the rate of crack propagation in asphalt mixtures using image analysis techniques. The techniques developed incorporate methods to observe the crack more clearly as well as a semiautomatic analysis of the images taken during 3 point bend tests on beams of asphalt. The results show that modified binders increase the resistance to crack propagation and that the path of least resistance to cracks appears to be the interface between the coarse aggregate and the matrix In addition a model is presented for both polymer modified and unmodified asphalts for calculating the effect of crack propagation on analytical design techniques. The model developed is based around the 3 point flexure of beams of asphalt and monitoring the degradation of load (stiffness) with time.

ISSN:1029-8436    

DOI:10.1080/10298439908901694

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Foaming waste glass, a new material produced from waste glass, is first briefly introduced. Secondly, the preliminary findings of the engineering properties required for improved pavement materials, namely unconfmed compressive strength qu, compressive splitting strength qs and the CBR value of the lime–stabilized Ariake clay (LA) with foaming waste glass (LAG) mixture, are presented on the basis of a series of laboratory tests. The potential effectiveness of foaming waste glass as a partial replacement for lime on the strengths of the LAG mixture is indicated by a comparison with lime-stabilized Ariake clay. A process for evaluating stabilized materials as pavement materials is described based on the results of a uniaxial test and pavement structure analysis. It is concluded that foaming waste glass can be effectively applied as a partial replacement for lime for the improvement of soft clay and that the LAG mixture could be used as pavement materials, considering not only its strength but its deformation properties as well.

ISSN:1029-8436    

DOI:10.1080/10298439908901695

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A new back-analysis method is suggested to assess the bonding condition between bituminous layers in addition to the pavement layer stiffnesses, from Falling Weight Deflectometer (FWD) test results. The shear bond stiffness at the interface is considered as a variable affecting the FWD deflections and therefore back-calculated in a similar manner to a layer stiffness. A sensitivity analysis carried out on theoretical pavements showed that, assuming full bonding between bituminous layers instead of the actual values will change the FWD back-analysed bituminous and sub-base stiffnesses by up to 50% and will not affect the sub-grade stiffness.

ISSN:1029-8436    

DOI:10.1080/10298439908901696

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

This paper presents the Findings of an effort undertaken by the Federal Highway Administration (FHWA) Long-Term Pavement Performance (LTPP) program to assess variability of distress data collected using a photographic method. The primary source of data used to characterize the film-derived distress data variability is the results of a distress survey conducted on 12 pavement test sections, including six asphalt concrete (AC) and six portland cement concrete (PCC) pavements. Distress surveys were performed by experts, individual raters, and two-person teams. A consensus survey on the pavements by a group of experts based on the photographic method was also conducted. Finally, a reference rating of the distress present on the same 12 test sections was performed using a consensus manual rating method by the same group of experts; data from these reference surveys were used as a surrogate of “ground-truth”. Based on the analyses of these data, variability of the film-derived distress data was evaluated and both apparent bias and precision for the data were quantified. It was observed that data interpreted by two-person teams were more consistent and showed smaller variations.

ISSN:1029-8436    

DOI:10.1080/10298439908901697

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:1029-8436    

DOI:10.1080/10298439908901692

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor