Title: Deflection-Based Approach for Pavement Layer Acceptance During Construction
Abstract: During construction of segments 5 and 6 of SH 130 toll road in Texas the Concessionaire funded the development of a deflection based approach to ensure the structural adequacy of each pavement layer. Recommendations were developed to conduct acceptance tests during construction on top of both the lime stabilized subgrade and the flexible base layers. A simple deflection based approach using the Falling Weight Deflectometer (FWD) was developed and implemented. The original pavement was designed using the AASHTO 93 design procedure and this design equation was used to calculate a composite modulus value on top of each layer in the structure. An approach was developed to compute the allowable maximum deflection for the calculated composite modulus value. For SH 130 the not to exceed deflection values at the 9000 lb load level were 39 mils on top of the lime layer and 19 mils on top of the flexible base layer. Prior to full implementation a pilot test area was identified. FWD testing was conducted in both wheel paths at 100 ft intervals. In locations where deflections higher than the target values were found additional Dynamic Cone Penetrometer (DCP) tests were conducted to determine the cause and the appropriate strengthening action. The results from that test are described in this paper. Overall the measured deflections were below the target values and the lime stabilized subgrade was found to be in compliance with the design assumptions and providing uniform support.
Publication Year: 2015
Publication Date: 2015-01-01
Language: en
Type: article
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