Laboratory Evaluation of Recycled Asphalt Pavement and Engineered Polymer Binder for Small Airfield Repairs

Conducting small asphalt repairs on airfields in remote locations can be technically and logistically challenging. An alternative to cold patch products is using an engineered polymer binder (EPB) mixed with recycled asphalt pavement (RAP). This paper presents the results of a laboratory evaluation of EPB with both wet and dry RAP. Compacted specimens were tested for rut resistance, indirect tensile strength (ITS), and Cantabro mass loss (ML). The results indicate that RAP mixed with EPB exhibited substantial rut resistance with ITS and ML similar to that of conventional dense-graded asphalt. Overall, the EPB and RAP blend appears to be a promising alternative for airfield repairs

Materials and Methods Used for the Expedient Repair of Concrete Pavements

Many traditional methods for the repair and rehabilitation of concrete pavements require meticulous construction processes with specialized equipment and long material curing periods in order to develop adequate strength and durability prior to returning the pavement to service. This paper summarizes the results of research projects conducted by the U.S. Army Engineer Research and Development Center in order to develop innovative pavement repair procedures and evaluate numerous commercial repair materials that can produce fast long-lasting repairs that facilitate the rapid re-opening of critical pavement infrastructure to traffic. This paper summarizes methods used for the certification and selection of suitable concrete pavement repair materials. In addition, this paper outlines the key activities included in expedient concrete repair processes. Thus, this paper provides a valuable summary of state-of-the-art concrete repair procedures and materials for the rapid and effective repair and rehabilitation of concrete pavements

Resilient moduli characterization of cement-treated silt

The performance of a flexible pavement depends on the resilient modulus (MR) of subgrade soil. Thus, MR is a key design parameter for mechanistic-empirical pavement design of flexible pavements. Generally, the resilient modulus is determined by conducting repeated load triaxial (RLT) tests in the laboratory and has been used to characterize the subgrade soil behavior under repeated traffic loading conditions. The use of cement to stabilize natural subgrade soils is widely accepted by transportation agencies. Several research studies were conducted on the resilient behavior of cementtreated soils. However, limited research studies have been conducted on the resilient behavior of cement-treated silty soil. Therefore, the current research study assessed the resilient moduli properties of cement-treated silt. Cement-stabilized soil specimens were statically compacted and cured in a humid room for a stipulated curing period before conducting RLT tests. RLT tests were conducted on cement-treated specimens at different cement dosages and curing periods to study the effect of the cement dosage and curing time on the resilient modulus. Test results indicated that a significant improvement in performance was observed after cement treatment. The untreated soil specimens exhibited stresssoftening behavior with an increase in deviator stress, whereas the cement-treated specimens exhibited stress-hardening behavior. The resilient modulus was increased with an increase in cement dosage. Regression analyses were conducted on RLT test results using three-parameter universal model and model parameters were determined. It was observed that the three-parameter universal model exhibited an excellent fit with experimental data