Roesler J.R.,University of Illinois at Urbana - Champaign |
Cervantes V.G.,Naval Facilities Engineering Service Center |
Amirkhanian A.N.,University of Illinois at Urbana - Champaign
International Journal of Pavement Engineering | Year: 2012
A new concept for designing concrete pavements by optimising the slab geometry in order to reduce the slab thickness as well as to minimise the mechanical load transfer devices has recently been proposed. Theoretically, the reduced slab size lowers the load and curling-induced tensile stresses and concomitantly a thinner concrete slab can be constructed. Full-scale test sections were constructed and tested under accelerated pavement loading conditions to validate this design concept hypothesis. The design and concrete material factors studied in this research were concrete thickness of 9, 15 or 20cm; granular or asphalt concrete base layer; and plain or fibre-reinforced concrete (FRC). A methodology was presented to convert the channelised traffic loading to equivalent single axle loads (ESALs) so that comparisons could be made between the various test sections. The accelerated pavement testing showed that shorter slab sizes can sustain a significant number of overloads and greater number of ESALs before developing cracking relative to standard jointed concrete pavements. The most prevalent distress observed was corner cracking which occurred twice as much as longitudinal cracks, whereas only 3 out of 46 cracking distresses were transverse cracks. The 20cm concrete slabs on granular base did not experience fatigue cracking for trafficking up to 51 million ESALs. The 15cm concrete slabs on granular base began cracking on an average of 11 million ESALs. As expected, the concrete slabs on asphalt base resisted a significant larger number of ESALs relative to the same concrete thickness on granular base. The cracking performance of the 9cm concrete slabs on granular base varied with the stiffness of the soil. For the 9cm slab thickness, structural fibres provided a longer fatigue life and extended service life relative to the plain concrete slabs. Finally, the smaller slab sizes maintained a medium-to-high load transfer efficiency over the accelerated loading period for all slab thicknesses without the development of any faulting. As expected, these slab systems resulted in higher deflections, and, therefore, the granular base and subgrade layers as well as lateral drainage system must be designed and specified to reduce the rate of permanent deformation and minimise the possibility of support erosion. © 2012 Copyright Taylor and Francis Group, LLC.
Tufenkjian M.R.,California State University, Los Angeles |
Thompson D.J.,Naval Facilities Engineering Service Center
Proceedings of the International Offshore and Polar Engineering Conference | Year: 2010
Accurate strength characterization of near surface seafloor soils is critical when designing and installing mat foundations and seafloor cable systems. This paper presents the results of an ongoing investigation to assess the merits of using flow penetrometer technology to aid the U.S. Navy's requirements for seafloor characterization in soft sediments. The paper presents the experiences learned from the preparation and consolidation of a large-scale clay specimen and discusses the penetration and extraction resistances measured using ball and cone penetrometers. The undrained shear strengths calculated with the cone, ball, and a vane are evaluated and compared. Copyright © 2010 by The International Society of Offshore and Polar Engineers (ISOPE).
Malvar L.J.,Naval Facilities Engineering Service Center
Transportation Research Record | Year: 2010
Several accidents involving aircraft punching through airfield pavements prompted the U.S. Navy to develop a technology for void detection. Initially, a successful void detection survey was completed at a naval air station where several voids were generated by leakage of large underground drainpipes. Various methods were used, such as internal videotaping of the pipes, heavy weight deflectometer (HWD) testing, testing with a ground-penetrating radar, and testing with a dynamic cone penetrometer (DCP). A state-of-the-art review was also completed to assess all existing technology applicable to void detection under pavements. However, the optimum technology (visual inspection and testing with an HWD and a DCP) still presented limitations because of the availability and speed of data acquisition, requiring prioritization of the work. A risk analysis was then completed and established work prioritization within each airfield and providing a prioritization of all U.S. Navy and Marine Corps airfield pavements. An interim policy and technical guidance (IP&TG) was issued on March 23, 2000, to establish the void detection methodology developed. This IP&TG was recently updated and included as an appendix in U.S. Department of Defense Unified Facilities Criterion UFC 3-260-03 and routinely applied at all 70 major U.S. Navy and Marine Corps airfields. This paper summarizes the methodology used and presents some recent field cases.
Dave E.V.,University of Illinois at Urbana - Champaign |
Ahmed S.,University of Illinois at Urbana - Champaign |
Buttlar W.G.,University of Illinois at Urbana - Champaign |
Bausano J.,Naval Facilities Engineering Service Center |
Lynn T.,APAC Central Inc.
Asphalt Paving Technology: Association of Asphalt Paving Technologists-Proceedings of the Technical Sessions | Year: 2010
This paper describes a comprehensive investigation of strain tolerant type reflective crack relief interlayer systems through fundamental laboratory testing, computer aided design, and accelerated pavement testing. One of the widely used methods to control the reflection of cracks from underlying, cracked pavement into a new asphalt overlay involve the use of conventionally paved 'interlayers' that tolerate the very high tensile and shear strain that exists above cracks and joints in the underlying pavement. While these systems often slow down the rate of reflective cracking relative to untreated control sections in the field, when cracks do appear they are often offset from the location of the underlying discontinuity. A recently completed study sponsored by the National Science Foundation led to the development of a new fracture test (ASTM D7313-07b - the Disk-Shaped Compact Tension Test for Asphalt Concrete) and new techniques for finite element modeling of fracture in asphalt overlay systems. After successful validation of these tools on three field projects, it was decided to conduct further validation using the Advanced Transportation Loading System or ATLAS device and to experiment with new overlay configurations. A large experimental matrix was used to select promising interlayer materials and pavement layer and joint configuration details using finit e element analysis. A 500 ft(165 m) test pavement was constructed, instrumented, and tested in the cold of winter in 2008. This paper describes this comprehensive investigation, the new test sections developed, the types of distress observed under accelerated loading, and how the results were used to validate a new mechanistic analysis and design tool. Moreover, significant new insights towards the mechanisms and prevention of reflective cracking were obtained and have been summarized.
Malvar L.J.,Naval Facilities Engineering Service Center |
Magallanes J.M.,Karagozian and Case, Inc. |
Wu Y.,Karagozian and Case, Inc.
Proceedings of the 8th International Conference on Structural Dynamics, EURODYN 2011 | Year: 2011
Results from numerical simulations are presented that investigate the behavior of concrete samples under standard laboratory strength tests. Samples include cylinder and cube specimens in compression and cylinder specimens for the splitting tension test. Each of these tests is commonly used to derive fundamental material properties for concrete, i.e. compressive and tensile strengths. Numerical models are developed for each of these tests using the finite element method and a recent release of the K&C concrete material model. Quasi-static solutions are then obtained using explicit time integration. The results indicate that the strength and failure modes for the compression tests can be highly influenced by the specimen shape and boundary conditions, in particular for the cube test. It is shown that ASTM C 1231 appears to provide the best estimate of compressive strength as a material property. The splitting tensile strength was confirmed to be slightly higher than the input tensile strength, suggesting that the proper material property input should be slightly smaller than the ASTM C 496 value.