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Rural roads, also known as low-volume roads are an indispensable part of the National Highway Network in China and its construction scale is huge. However, in the western areas, the investment on rural roads is not enough and the traffic volume is low. This paper studies how to utilize non-standard and local materials for constructing these rural roads. The properties of some local materials, such as shale soil and low-strength sandstone, are stabilized with different inorganic binders (cement, lime, and fly ash). Different mixing proportions are studied. Several performance indexes including unconfined compressive strength, splitting strength, and water stability of these stabilized local materials are also evaluated. On the basis of lab experimental results, the test road has been built. This paper shows that the property of soft-aggregates is similar to that of hard aggregates in base layers for rural roads, and these local materials are completely usable for constructing rural roads if suitable methods and technologies are adopted.

The Projects NCHRP9-19 and 9–29 in the USA have researched and developed SPT (Simple Performance Test), which can be used to test asphalt mixture's dynamic modulus, static creep and permanent deformation under repeated loading and analyze the visco-elasticity of asphalt mixture. This article, based on the modified Burgers model and Boltzmann superposition principle, figures out visco-elasticity model parameters using the data observed from permanent deformation under repeated loading in SPT. A prediction model is established between the modified Burgers model and the permanent deformation in a wheel tracking test. The test shows that the estimated value from the established predicting model is very close to the measured value through a wheel tracking test, which means, to some extent, that the predicting model illuminates the inherent relation between the two methods to evaluate permanent deformation of asphalt mixture.

Packing model of aggregate is a very important issue in gradation design and research on asphalt mixture. The packing characteristics of coarse aggregate and fine aggregate can affect the skeleton and volumetric parameters, such as VMA (Void in Mineral Aggregate), of asphalt mixture respectively. In this study, based on the ideal packing model of aggregate, the 2-D packing model, which is a random distribution and compacted contact of different size aggregates, is built and the mathematical solution to this model is figured out by using the geometric theory of space topology. The model has been programmed and visualized by using Visual Basic language. The impact of gradation on the skeleton and VCA (Void in Coarse Aggregate), and the effect of fine aggregate packing on VMA can be analyzed by using this model and algorithm. The model is helpful to the gradation design, analysis and evaluation for asphalt mixture.

Pavement skid resistance, which depends on slip speed, is an important factor impacting traffic safety. To deeply understand the relationship of asphalt pavement skid resistance to slip speed, field tests are conducted using Dynamic Friction Tester (DFT) at 33 test sites of 11 sections with various highway grades and surface types. Friction coefficients corresponding to various slip speeds (0 km/h through 80km/h by 0.1 km/h) are obtained for each test site. Evaluations show that the Penn State Model is not suitable for characterizing the curve of slip speed-friction coefficient measured by DFT. Then, a new model with 3 parameters is developed. Regression analysis of the 33 DFT measurements shows that the new model can accurately describe the relationship of asphalt pavement skid resistance to slip speed measured by DFT. It has the potential to improve skid resistance evaluation of asphalt pavement.