Full-Scale Laboratory Evaluation of the Effectiveness of Subgrade Soil Stabilization Practices for Portland Cement Concrete Pavements Patching Applications

2020 ◽  
Vol 2674 (5) ◽  
pp. 465-474
Author(s):  
Ali Behnood ◽  
Jan Olek
Keyword(s):  
Soil Stabilization ◽  
Fatigue Loading ◽  
Full Scale ◽  
Laboratory Evaluation ◽  
Concrete Pavements ◽  
Portland Cement Concrete ◽  
Flowable Fill ◽  
Stabilized Soil ◽  
Adequate Quality ◽  
Base Course

Adequate quality of subgrade under patched areas can extend the service life of concrete pavements and reduce their maintenance costs. In this study, the performance of various subgrade stabilization scenarios was evaluated and compared with each other in a full-scale laboratory-based setup. For this purpose, a test box with the footprint of 6 × 6 ft and a height of 4 ft was constructed using C steel channels. The test box was used to investigate the effects of various types of soil stabilization methods, such as chemical (cement) stabilization, use of aggregate base course (ABC), geogrid (GG) and geotextile (GT) with ABC, GT with cement-stabilized soil, GT with in-situ compacted soil, flowable fill, and lean concrete. The test results showed that all stabilization techniques successfully improved the performance of the subgrade layer by decreasing the deformation under the fatigue loading representing a single axle load of 9,000 lbf/tire. The use of GT with aggregate-based layers was found to significantly reduce the amount of settlement. Subgrade layers stabilized with GG also experienced lower values of deformations compared with the unmodified (control) section. However, GG was not as effective as GT. The use of cement-treated aggregate and lean concrete reduced the deformations to negligible levels.

scholarly journals Development of Subgrade Stabilization and Slab Undersealing Solutions for PCC Pavements Restoration and Repairs

2020 ◽  
Author(s):  
Ali Behnood ◽  
Jan Olek
Keyword(s):  
Best Practices ◽  
Soil Stabilization ◽  
Concrete Pavements ◽  
The Poor ◽  
Subgrade Soil ◽  
Flowable Fill ◽  
Subgrade Stabilization ◽  
Improved Performance ◽  
Grouting Materials

The loss of functionality and the development of distress in concrete pavements is often attributable to the poor subbase and subgrade conditions and/or loss of support due to the development of the voids underneath the slab. Subgrade soil stabilization can be used as an effective approach to restore the functionality of the subgrades in patching projects. This research had two main objectives: (1) identifying the best practices for soil stabilization of the existing subgrade during pavement patching operations and (2) identifying and developing new, modified grouting materials for slab stabilization and undersealing. Various stabilization scenarios were tested and showed improved performance of the subgrade layer. The use of geotextile along with aggregate course was found to significantly reduce the settlement. Non-removable flowable fill was also found to significantly reduce the subgrade settlement. Cement-treated aggregate and lean concrete provided the best performance, as they prevented formation of any noticeable settlement in the underlying subgrade.

The Rationale for Update of S-N Curves for Single Sided Girth Welds for Risers and Pipelines in DNV GL RP C-203 Based on Fatigue Performance of More Than 1700 Full Scale Fatigue Test Results

2018 ◽  
Author(s):  
Agnes Marie Horn ◽  
Inge Lotsberg ◽  
Oddvin Orjaseater
Keyword(s):  
Deep Water ◽  
Fatigue Testing ◽  
Fatigue Loading ◽  
Full Scale ◽  
Fatigue Performance ◽  
Test Results ◽  
Severe Fatigue ◽  
Adequate Quality ◽  
Two Phases ◽  
Girth Welds

Deep-water tendon and riser systems are often subjected to severe fatigue loading from waves, currents and vessel movements. The girth welds between successive lengths of pipe or at pipe terminations represent fatigue-critical features where failure would be catastrophic. Hence, validation fatigue testing by full scale pipes of the most critical welds are often performed to ensure adequate quality and/or to document a better S-N curves than those available in standards today like DNVGL-RP-C203 [1] and BS7608 [2]. To better understand the fatigue performance with respect to identify trends, dependencies and critical features that influence the fatigue performance, a JIP on Fatigue of Girth Welds were initiated in 2011. Two phases have been conducted and a total of 1700 full scale one sided girth welds, mostly run by Stress Engineering, have been statistically analyzed. The test data has been interrogated to investigate the effect of as-welded condition, OD ground, OD/ID ground, un-reeled pipe, reeled pipe, thickness and effect of misalignment. Based on these analyses, new S-N curves for risers and pipelines have been included in DNVGL-RP-C203 for non-reeled girth welds. This paper presents the findings and trends from the JIP work which has been the rationale for the updates of girth welds in section 2.10 in DNVGL-RP-C203 2016 edition.

Determination of Sample Size and Influencing Factors to Characterize Faulting in Jointed Concrete Pavements

2021 ◽  
pp. 036119812199670
Author(s):  
Ruohan Li ◽  
Jorge A. Prozzi
Keyword(s):  
Sample Size ◽  
Plain Concrete ◽  
Concrete Pavements ◽  
Portland Cement Concrete ◽  
Federal Highway ◽  
Significant Difference ◽  
Jointed Concrete Pavement ◽  
Functional Classes ◽  
High Precipitation ◽  
Departments Of Transportation

The objective of this study is to evaluate the field variability of jointed concrete pavement (JCP) faulting and its effects on pavement performance. The standard deviation of faulting along both the longitudinal and transverse directions are calculated. Based on these, the overall variability is determined, and the required sample sizes needed for a given precision at a certain confidence level are calculated and presented. This calculation is very important as state departments of transportation are required to report faulting every 0.1 mi to the Federal Highway Administration as required by the 2015 FAST Act. On average, twice the number of measurements are needed on jointed reinforced concrete pavements (JRCP) to achieve the same confidence and precision as on jointed plain concrete pavements (JPCP). For example, a sample size of 13 is needed to achieve a 95% confidence interval with a precision of 1.0 mm for average faulting of JPCP, while 26 measurements are required for JRCP ones. Average faulting was found to correlate with several climatic, structural, and traffic variables, while no significant difference was found between edge and outer wheelpath measurements. The application of Portland cement concrete overlay and the use of dowel bars (rather than aggregate interlock) are found to significantly reduce faulting. Older sections located on higher functional classes, and in regions of high precipitation or where the daily temperature change is larger, tend to have higher faulting, and might require larger samples sizes as compared with the rest when faulting surveys are to be conducted.

Measuring As-Constructed Smoothness of Portland Cement Concrete Pavements with Lightweight Profilometers

2001 ◽  
Vol 1764 (1) ◽  
pp. 189-200
Author(s):  
Mahmuda Akhter ◽  
Mustaque Hossain ◽  
Jeffrey Hancock ◽  
John Boyer ◽  
William J. Parcells
Keyword(s):  
Portland Cement ◽  
Concrete Pavements ◽  
Portland Cement Concrete ◽  
Cement Concrete

Full-Scale Evaluation of Relatively Thin Airfield Pavements

2020 ◽  
Vol 2674 (10) ◽  
pp. 658-669
Author(s):  
W. Jeremy Robinson ◽  
Jeb S. Tingle ◽  
Carlos R. Gonzalez
Keyword(s):  
Asphalt Concrete ◽  
Test Section ◽  
Concrete Surface ◽  
Full Scale ◽  
Test Items ◽  
Pavement Structures ◽  
Base Course ◽  
And Performance ◽  
Rutting Behavior ◽  
Aggregate Base

A full-scale airfield pavement test section was constructed and trafficked by the U.S. Army Engineer Research and Development Center (ERDC) to evaluate the performance of relatively thin airfield pavement structures. The test section consisted of four test items that included three asphalt pavement thicknesses and two different aggregate base courses. The test items were subjected to simulated aircraft traffic to evaluate their response and performance to realistic aircraft loads. Rutting behavior, instrumentation response, and falling weight deflectometer response were monitored at selected traffic intervals. It was found that the performance of the airfield pavement sections were most sensitive to aggregate base course properties, where a 50% reduction in base course strength resulted in a 99% reduction in allowable passes. The data suggested that when sufficient asphalt thickness is not provided, the failure mechanism shifted from subgrade failure to base course failure, particularly at higher subgrade CBR values. In addition, the number of aircraft passes sustained was less than that predicted by current Department of Defense (DOD) methods that include assumptions of a high-quality aggregate base and a minimum asphalt concrete thickness. The results of this study were used to extend existing DOD pavement design and evaluation techniques to include the evaluation of airfield pavement sections that do not meet the current criteria for aggregate base quality and minimum asphalt concrete surface thickness. These performance data were used to develop a new base failure design curve using existing stress-based design criteria.

Microscale Heat Island Characterization of Rigid Pavements

2017 ◽  
Vol 2639 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Sushobhan Sen ◽  
Jeffery Roesler
Keyword(s):  
Radiative Forcing ◽  
Time Lag ◽  
Thermal Inertia ◽  
Concrete Pavements ◽  
Heat Island ◽  
Rigid Pavements ◽  
Subsurface Layers ◽  
Urban Heat ◽  
Base Course

Rigid pavements have an impact on the urban heat island (UHI) and hence the surrounding environment and human comfort. Currently, most studies use a mesoscale approach in UHI characterization of pavements. This study proposes a microscale approach that can be incorporated into a pavement life-cycle assessment (LCA). The heat flux of various concrete pavements containing layers of varying thermal diffusivity and inertia was simulated. The surface pavement radiative forcing (RFp) was developed as a metric for use in a pavement LCA. Additionally, the heat conducted and stored in each concrete pavement system was analyzed using an average seasonal day metric to understand the temporal pavement energetics. Of the various thermal cases, only a higher albedo surface significantly changed the RFp for a fixed climate. However, a time lag was induced by the thermal inertia of the base course, which decreased the amount of heat conducted out of the pavement at night by storing heat in the base course for a longer time, effectively reducing nighttime UHI. Diurnal variations in thermal behavior can be controlled by changing the thermal properties of subsurface layers, which can be used to partially mitigate UHI.

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