Author: William Edward Wolfe Publisher: ISBN: Category : Pavements Languages : en Pages : 46
Book Description
Environmental instruments to measure temperature, soil moisture and frost depth were installed at five test sections of the SHRP pavement project on U.S. 23 north of Delaware, Ohio. At three of these locations tensiometers, which a designed to measure negative pore pressures, were added to the instrumentation package. The pore pressures as recorded by the tensiometers have increased from initially negative to positive values at each location and throughout the profile in the first year after installation of the instrument package was completed. At the same time, data collected from the moisture probes were showing a corresponding increase in soil moisture content. Samples of an aggregate base and clayey subgrade material were collected at several locations on the DEL 23 project by ODOT. They were delivered to the OSU soil mechanics laboratory for classification and permeability determination. The aggregate base conformed to ODOT material specification Item 304. Measured permeability coefficients ranged between 2x10 [to the minus 2] and 2.9x10 [to the minus 2] cm /sec. The clayey material was classified as a low plasticity clay (AASHTO Classification A-6 to A-7-6) with permeability coefficients ranging between 1x10 [to the minus 6] and 4x10 [to the minus 8] cm/sec.
Author: Andrew G. Heydinger Publisher: ISBN: Category : Pavements Languages : en Pages : 76
Book Description
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.
Author: Andrew G. Heydinger Publisher: ISBN: Category : Pavements Languages : en Pages : 166
Book Description
Long-Term Pavement Performance (LTPP) Seasonal Monitoring program (SMP) instrumentation was installed in pavement sections at the Ohio SHRP Test Road. The pavements are monitored for the seasonal variations of moisture, temperature and frost penetration. Data from the instrumentation is subjected to quality checks and prepared for uploading to the FHWA Information Management System (IMS). Findings from the testing are to be incorporated into future pavement design procedures.
Author: William Edward Wolfe Publisher: ISBN: Category : Frost Languages : en Pages : 118
Book Description
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.
Author: Publisher: ISBN: Category : Pavements Languages : en Pages : 164
Book Description
Performance and environmental data continued to be monitored throughout this study on the Ohio SHRP Test Road. Response testing included three new series of controlled vehicle tests and two sets of nondestructive tests. Cracking in two SPS-2 sections with lean concrete base confirmed observations elsewhere that PCC pavement may not perform well when placed on rigid base. Of the five types of base material used on LOG 33 and evaluated for their effect on AC pavement performance, deflection measurements on the asphalt treated base fluctuated most with changes in temperature. None of the other bases were sensitive to temperature. Cement treated base had the lowest deflection. On unbound material, bases containing large size stone gave the lowest deflection. The preponderance of data collected in the laboratory and at the ERI/LOR 2 site suggests that PCC pavement performs poorly on 307 NJ and CTFD bases. All sections with 25-foot slabs, except those with ATFD base, and the section with 13-foot slabs on 307 NJ base had significant transverse cracking. The 13-foot long slabs with 307 NJ base also had some longitudinal cracking. Considering the relatively short time these pavement sections had been in service, this level of performance was considered unacceptable. The ATFD base appeared to be performing best. On JAC/GAL 35, subgrade stiffness had a significant effect on dowel bar response. Looseness around dowel bars affected their ability to transfer load. Larger diameter and stiffer dowel bars provided better load transfer across PCC joints. The most effective dowel bar in these tests was the 1.5" diameter steel bar. The performance of 1" steel dowel bars were similar to 1.5" fiberglass bars. One-inch diameter fiberglass dowel bars were not recommended for PCC pavement. While undercutting PCC joint repairs initially reduced the forces in dowel bars, the effectiveness of the undercut diminished over time. Dowel bar forces were about the same in the Y and YU types of joint repairs after some time.
Author: William Edward Wolfe
Author: Andrew G. Heydinger
Author: Andrew G. Heydinger
Author: Anand J. Puppala
Author: William Edward Wolfe
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Author: Phillip S. K. Ooi