Advanced Materials Research Vol. 723

Abstract: This study deals with the Austroads (2008) Guide to Pavement Technology Part 2: Pavement Structural Design on which most road pavement designs in Australia are based. Flexible pavement designs and performance predictions for pavements containing one of more bound layers derived from the mechanistic Austroads pavement design methodology and the AASHTO-2004 approach are compared for Australian conditions, with consideration of subgrade and other material properties and local design preferences. The comparison has been made through two well-known programs namely CIRCLY (5.0) and KENLAYER. The study shows that each guide has its own advantages and disadvantages in predicting stress and strain in pavement layers under different conditions. The study recommends that modifications are necessary resulting in more realistic and longer lasting pavements in Australia.

Abstract: Modelling granular pavement materials has a significant role in the pavement design procedure. Modelling can be through an experimental or numerical approach to predict the granular behaviour during cyclic loading. The current design process in Australia is based on linear elastic analysis of layers. The analysis is performed through a well-known program CIRCLY which is applied to model bound pavement material behaviour. The KENLAYER is one of the common pavement software models used for pavement design in the United States which performs non-linear analysis for granular materials. Alternatively, a general Finite Element program such as ABAQUS can be used to model the complicated behaviour of multilayer granular materials. This study is to compare results of numerical modelling with these three programs on two sample pavement models.

Abstract: Aging is a main factor affecting the durability of asphalt pavement. To study decay behavior of asphalt pavement with aging, aged asphalt was extracted from stratified pavement mixtures for different service-life. The changes of asphalt properties with service time and depth variations of the pavement were discussed. And numerical simulation analysis of pavement structure was conducted with pavement gradient modulus changes caused by aging. The results indicate that asphalt stiffness increases and low-temperature performance decays sharply with the extension of pavement service life, especially in the first several years. The vertical aging differences from top to bottom of pavement were significant, the aging extents decrease continuously from the surface, which cause the gradient changes of pavement modulus. The maximum tensile stress and maximum shear stress all increase with surface modulus increasing, so more serious aging can induce greater gradient modulus, shear stress and tensile stress are larger under the same loads, which have more serious damage to the pavement structure.

Abstract: This study was set out to analyze and investigate the damaged surface course of a newly-constructed road pavement within the two years after its completion. Because the idea of sustainable public infrastructure in Taiwan has recently encouraged the use of renewable materials in the design phase, parts of this roads pavement structure is composed of recycled asphalt concrete, renewable agents, disposed construction surplus and the like. Considering the complex relationship between the damaged condition of the road pavement and factors such as its load repetitions, its design, its construction process and management, and road management, this study employed an intelligent vehicle for pavement survey, Benkelman Beam method, GeoGauge, and Ground Penetrating Radar to examine the roads pavement structure. After cross-analyzing the results from the non-destructive testing, certain parts of the road and the possibly-damaged structure of the pavement were sampled for material testing. The results from the material testing indicated that the related mechanical parameters of the road sections sampled by the non-destructive testing were significantly lower than the normal standards. Moreover, the results from the GPR analysis revealed that the water content of the subgrade of the severely-damaged road sections was high. The low loading capacity of the pavement structure was mainly due to the high groundwater water level in the surrounding area and the penetration of the rain into the cracks of the surface course. This study proposes that nondestructive testing can facilitate sampling sections for material testing to better ensure the quality of the construction although random sampling is commonly seen in the standard material testing for acceptance of completed work. In addition, the study suggests that non-destructive testing can be one requirement for the acceptance of completed work in pavement projects with renewable materials to better evaluate the quality of the pavement after its construction.

Abstract: Although there is a large population in the limited space of metropolitan areas in Taiwan, but many manholes are often set on the pavement, which impact the quality of the pavement service and lead to public complaints. In recent years, the manholes have been gradually buried under the pavement on policy, so as to improve administration performance of government. The construction quality at the location of manhole is not easy to control, and often leads to the pavement damaged. This study assesses the differences of the temperature changes at manhole location from the general asphalt concrete when paved with asphalt concrete using the infrared thermal imager. The study found that the use of infrared thermal imager can get the difference of temperature of asphalt concrete pavement between the manhole position and the non-manhole position, and also can determine the position and width of manhole, so as to help to the construction compaction and quality control. Furthermore, because the temperatures of pavement at manhole position and non-manhole position are different, when the pavement damaged and need to dig the pavement for maintaining, the infrared thermal imager can be used to find nonmetallic manhole for construction management reference.

Abstract: Because of the small thickness, the mixture temperature of Ultra Thin Friction Courses (UTFC) decreased quickly during construction process, which causes the great difficulty to guarantee the pavement compaction, especially for the dense gradation asphalt mixture. In order to solve this problem, Polyolefin and SBS modified asphalt (Abbrev. PSA) mixture was designed. Volumetric properties, compaction characteristics, water sensitivity, as well as high/low temperature performance of the mixture were investigated. Laboratory test results show the PSA mixture has very good high temperature performance and other beneficial characteristics. Field tests show that the new asphalt mixture possesses very good pavement performance, as well as easily to be constructed. The PSA mixture can be used as preventive maintenance and repair materials.

Abstract: The main objective of this study is to evaluate the noise generated due to tyre-pavement surface interaction for various modes and to develop a noise prediction model for each mode by taking into account various factors affecting the noise generation. Eight asphalt pavement and four cement concrete pavement stretches were selected for measurement of the noise. Tyre-pavement interaction noise was measured using controlled pass-by method by eliminating the noise generated from engine and the vehicle exhaust systems. Noise levels were measured as a function of vehicle type, vehicle speed, loading condition, pavement temperature, direction of wind, and type of pavement. The influence of each of these variables are analyzed and quantified in this paper. The vehicle speed is found to be the most significant variable affecting the noise generated due to tyre-pavement surface interaction followed by other variables. Further, individual noise prediction models are developed for each mode in each survey location and a combined tyre-pavement interaction noise model is developed for each mode for both asphalt and cement concrete pavements.

Abstract: in order to find a suitable pavement and develop a reasonable pavement design method for southern warm continental climate regions, both experiment roads and finite element simulations are employed in this research. In experiment roads, strain detectors are buried at the bottom of asphalt layers to measure its strains and calculation models. Road design parameters such as road surface deflections and damage predictions such as plastic permanent deformations are calculated and compared between different pavements. Pavement deformation and design control parameter are made. Finally, a suggested reasonable pavement satisfying climate conditions and traffic flow needs is proposed.

Abstract: This study evaluates the structural responses for an eighteen-wheel vehicle in a flexible pavement with numerical analysis. The predicted stress and strains are compared with the field measured values. As a first step, a Finite Element Model (FEM) of the instrumented section is developed in commercial finite element software, ABAQUS. Stiffness of each layer is obtained by Falling Weight Deflectometer (FWD) test and backcalculated by ELMOD. The stress and the strain responses at some predefined locations are determined. Secondly, a total of 40 sensors are installed on Interstate 40 (I-40) at mile post 141 in New Mexico, to measure the stress-strain, loading configurations and environmental variations in the pavement. The outputs of the FEM are compared with the field measured values. Results show that the field responses closely match with the developed FEM model and thus, verify the numerical analysis.