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Potential benefits in applying polypropylene fiber to stabilize expansive soils and cement treated bases is already been reported in previous studies. So a critical need exists to incorporate the use of fiber into the Texas Department of Transportation's (TxDOT's) Guidelines for Modification and Stabilization of Soils and Base for Use in Pavement Structures. The present paper discusses the results collected from the first experiment al test section on FM897 in the TxDOT Paris District. Three 500-ft (152.4m) test sections were constructed with 2 percent cement on FM897 in February 2020 in the north bound lane loaded truck direction which includes a new sandstone base, full depth reclamation (FDR), and control. However, only the new sandstone base and FDR sections were built with fiber. In this project, two types of fibers were used--(a) fibrillated fiber Fibermesh300, and (b) macro-synthetic fiber Enduro 600.The surface and base layers from the new sandstone base section were removed and used for the edge widening area of the FDR and control sections. Based on the laboratory tests, the optimum fiber contents were found to be 0.6 percent and 0.4 percent for a new sandstone base and FDR, respectively. The laboratory Unconfine Compression Strength (UCS) results showed significant improvements (>112.36 percent) when fibers were added to the sandstone base. To have better control, fiber and cement were manually distributed, following the US Army Corps of Engineers' recommendations. Because of unexpected construction equipment failure that caused compaction delays of approximately 5 hours, cement was in contact with moisture for approximately 5 hours before compaction. UCS results showed an approximate 55 percent reduction when there was a 5-hour delay from the time water was introduced (resulting in the start of the hydration process) until the time of compaction. It indicated that there are detrimental effects on UCS i f there is delay on compaction. There were significant reductions on the normalized W1 deflections at 5 months after construction. In particular, the FDR and new sandstone base sections (with fiber) experienced over 52 percent reduction as compared to 1 week after construction FWD data. Furthermore, the averaged W1 deflections were lower than before construction for both FDR and new sandstone base sections (with fiber). This indicates that there were rapid increases in structural capacity and significant strength developed in the fiber sections between 1 week and 5 months. Further research is needed to explain the mechanism and phenomena. [ABSTRACT FROM AUTHOR]

The article discusses the developments of the technologies implemented by the Texas Department of Transportation (TxDOT) to address the challenges on the pavement structural conditions in the state. It provides brief overview of the implementation projects and the testing devices the agency used to determine the condition of its pavement structure. The agency also utilizes the Rolling Dynamic Deflectometer (RDD) to check for reflective cracking potential.

An introduction is presented in which the editor discusses various reports within the issue on topics including the innovative transportation technology, pavement research and surface properties.

Transverse cracking is a major distress in asphalt pavements in north-western Oklahoma. Assessment of probable causes of such distresses is helpful to the design of new pavements and maintenance and rehabilitation of existing pavements. In this study, probable causes of transverse cracking were identified using field investigation and a parametric study using AASHTOWare Pavement ME Design. Specifically, non-destructive and destructive tests were performed on two flexible pavement sections, namely US 270 and US 287 in Oklahoma. Also, soil samples and asphalt cores were collected for laboratory testing. The Ground Penetrating Radar results revealed that the disturbance zone was confined within the pavement structure and cracks were generated at the surface and propagated downward at both sites. The Dynamic Cone Penetration and Falling Weight Deflectometer test results indicated that both pavement sections were structurally adequate to support the current level of traffic for 10 years or more, with proper maintenance. The cracking resistance of the asphalt cores collected from both pavement sections was ranked as poor based on the Illinois Flexibility Index Test. The field and laboratory investigations indicated that stiffer and brittle asphalt mixes at both sites resulting from aging during the long service life were primarily responsible for the transverse cracking observed in the field. Also, a large number of thermal cycles with significant difference between low and high temperature, observed from the weather data, was a likely contributing factor. In addition to field and laboratory investigations, a parametric study was conducted using the AASHTOWare Pavement ME Design. The influence of the changes in pavement structural components, material properties and the average hourly temperature on transverse cracking was examined. Binder grade and pavement thickness were found to be the most influential factors. A hybrid approach involving field and laboratory testing and a parametric study using the AASHTOWare Pavement ME Design was found to be a useful tool for assessment of probable causes of transverse cracking in asphalt pavements. [ABSTRACT FROM AUTHOR]

Traditionally, traffic loading characteristics are collected for pavement design and performance prediction purposes using permanent roadside weigh-in-motion (WIM) stations. However, high installation and maintenance costs associated with these permanent WIM stations dictate that their deployment be mostly limited to major highways, such as the interstate network. Quite often however, pavement damage on high volume rural highways with heavy truck proportions is more severe than anticipated, and there is no effective way of quantifying the traffic loading on these highways. Therefore, this study was conducted to evaluate the potential application of portable WIM systems as a means for bringing the WIM technology to these high volume rural highways. A portable WIM unit was deployed in the Texas overweight corridor in Hidalgo County (Pharr District) near the USA-Mexico border on highway FM 1016 for collecting traffic data for a minimum of three weeks in each direction. The collected traffic data were analyzed to generate traffic parameters such as volume, load spectra, and overloading information both in terms of the gross vehicle weight (GVW) and axle weight. The computed traffic parameters were successful in partially explaining some of the existing pavement conditions on this highway. Overall, the study findings indicated that the portable WIM unit can be used as a convenient and cost-effective means for collecting reliable traffic information for design, analysis, and monitoring purposes. However, proper in-situ calibration of the portable WIM unit at each site is imperative prior to any real-time traffic data collection. [ABSTRACT FROM AUTHOR]