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Monitoring of the environmental instrumentation installed under select pavement sections constructed by the Ohio Department of Transportation (ODOT) in 1995 on US 23 in Delaware County, Ohio was continued. The measurements made consisted of soil moisture, temperature and frost depth profiles.
"It is a well recognized fact that pavements with poor subsurface drainage properties prematurely exhibit distress and have higher life-cycle cost. Thus, providing adequate subsurface drainage in a pavement system to remove the infiltrated moisture in a timely manner is an important design consideration. Currently, Ohio Department of Transportation (ODOT) accepts several types of materials specifications for use as drainable base materials. They are ODOT 307 (NJ, IA, and CE), ODOT 308 (asphalt treated), and ODOT 306 (cement treated). However, the effectiveness of these base materials in actual service has not been conclusively established in previous ODOT studies. Consequently, a research project, so-called ATB-90, was initiated in 2002 to provide additional data to asses the merits of the drainable bases in the asphalt pavement. At the present time, most of the current drainage criteria have been developed on the basis of describing water flow in saturated conditions. Yet this could happen in a very limited circumstance and time duration. In this study, a transient analysis using SEEP/W program was conducted to simulate water flow in a flexible pavement system. A new predictive equation along with design charts for estimating the time required to drain 50 percent saturation were developed by utilizing the results of SEEP/W analysis. The predictive equation could be used to design a flexible pavement system for effective subsurface drainage."--Abstract.
Civil infrastructure systems are generally the most expensive assets in any country, and these systems are deteriorating at an alarming rate. In addition, these systems have a long service life in comparison to most other commercial products. As well, the introduction of intelligent materials and innovative design approaches in these systems is painfully slow due to heavy relianceon traditional construction and maintenance practices, and the conservative nature of design codes. Feedback on the "state of the health" of constructed systems is practically nonexistent. In the quest for lighter, stronger and corrosion-resistant structures, the replacement of ferrous materials by high-strength fibrous ones is being actively pursued in several countries around the world, both with respect to the design of new structures as well as for the rehabilitation and strengthening of existing ones. In North America, active research in the design of new highway bridges is focused on a number of specialty areas, including the replacement of steel reinforcing bars in concrete deck slabs by randomly distributed low-modulus fibers, and the replacement of steel prestressing cables for concrete components by tendons comprising super-strong fibers. Research is also being conducted on using FRPs to repair and strengthen existing structures.
Seasonal Monitoring Program (SMP) instrumentation was installed in five sections at the Ohio Test Pavement in Delaware County, Ohio using Strategic Highway Research Program (SHRP) protocols developed for the Long-Term Pavement Performance (LTPP) group to the Federal Highway Administration (FHWA). The SMP instrumentation monitors pavements for temperature and pavement bases and subgrade soils for variations in moisture, temperature, and frost penetration. Time Domain Reflectometry (TDR) instrumentation was installed onsite in two sections for monitoring the moisture. Thermal conductivity sensors (TCS) were installed in four sections to measure soil moisture suction. Laboratory soil-water characteristic tests were conducted on remolded subgrade soil.--The TDR volumetric moisture contents typically varied by 10% to 15% from the driest to the wettest periods, but sometimes the variations were larger. The lower water contents occurred during the late winter/early spring months and the higher contents occurred during the late summer/early fall months. This reflects the climatic conditions that occurred. Some of the TDR moisture contents exceeded 40%, wich is greater than the soil porosity and therefore not possible. An equation for TDR volumetric water content developed for the FHWA yields lower water contents. Most of the thermal conductivity sensors are no longer within calibration. Data from sensors in calibration indicate very low matric suctions, which is consistent with high water contents. Soil-water characteristic relationships were obtained for the subgrade soil using trizxial and pressure plate apparatus. The relationships from the two tests are comparable. The soil exhibits some hysteresis when comparing drying and wetting curves.
"TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 433: Significant Findings from Full-Scale Accelerated Pavement Testing documents and summarizes significant findings from the various experimental activities associated with full-scale accelerated pavement testing (f-sAPT) programs that have taken place between 2000 and 2011. The report also identifies gaps in knowledge related to f-sAPT and where future research may be needed. NCHRP Synthesis 433 is designed to expand the f-sAPT base of knowledge documented in NCHRP Syntheses 325 and 235, both with the same title of Significant Findings from Full-Scale Accelerated Pavement Testing. f-sAPT is the controlled application of a wheel loading, at or above the appropriate legal load limit, to a pavement system to determine pavement response in a compressed time period. The acceleration of damage is achieved by one or more of the following factors: increased repetitions, modified loading conditions, imposed climatic conditions, and thinner pavements with a decreased structural capacity which have shorter design lives"--
This synthesis will be of interest to pavement engineers, safety officers, and others interested in wet-pavement safety programs. Information is provided on the programs used by a number of agencies in gathering data and correcting areas of potential wet-weather accidents. Wet-pavement accidents continue to be of concern to highway agencies. This report of the Transportation Research Board summarizes agencies' programs in areas such as accident reporting, vehicle testing, friction testing, corrective actions for problem areas, and tort liability and gives some general guidelines for the content of a wet-pavement safety program.
Introductory technical guidance for civil engineers, construction managers and highway maintenance managers interested in pavement engineering. This is one of two volumes. This is what is contained in this volume: 1. AGGREGATE SURFACE PAVEMENTS 2. THIN ASPHALT PAVEMENT OVERLAYS 3. CONCRETE ADMIXTURES FOR PAVEMENT 4. ACOUSTIC SPECTROSCOPY FOR ASR TESTING OF CONCRETE PAVEMENT 5. BASES AND SUBBASES FOR CONCRETE PAVEMENT 6. INTERNAL CURING OF CONCRETE PAVEMENT 7. PAVEMENT FOR SEASONAL FROST CONDITIONS 8. PAVEMENT DRAINAGE 9. FLEXIBLE ASPHALT CONCRETE 10. ELASTIC LAYERED METHODS OF FLEXIBLE PAVEMENT DESIGN 11. COMPACTION AND QUALITY CONTROL FOR HOT MIX ASPHALT PAVEMENT 12. SURFACE PREPARATION AND PLACEMENT FOR HOT MIX ASPHALT PAVEMENT 13. PAVEMENT SURVEY, MAINTENANCE AND REPAIR 14. PAVEMENT OVERLAYS.