Louisiana Transportation Research Center (LTRC) has conducted a research study on LA 493 that provides evidence of damage to roadways caused by inundation. The evidence supporting this comes from three sources: a rod and level cross-section survey taken approximately one month prior to the first inundation event and subsequent cross-section surveys taken after the first to third inundation events; from pavement assessments with LTRC’s profiler in June 2017 and June 2018; and from a structural assessment with the falling weight deflectometer (FWD). Differential movements of the roadway surface were measured after the inundation events. The elevation increase at the centerline of the test sites varied from 2.44 mm to 44.5 mm after the first inundation event. Movements such as those measured will adversely affect the pavements performance leading to a reduced service life. Results from the IRI testing implied that (1) there were high degrees of differential profile changes in the roadway surface, (2) the IRI was significantly higher than it should have been for a roadway with its service age, and (3) there was a high degree of IRI variation amongst the test sites. Data from rutting tests also had high degrees of variability. The maximum measured rut depth was 1.685 in. Longitudinal crack data implied that (1) most of the sites had excessive longitudinal cracking for the time that they were in service, (2) the longitudinal cracking observed is consistent with volumetric changes occurring in the subgrade, and (3) it is logical to infer that the inundation events were responsible for both the magnitude and premature emergence of these longitudinal cracks. Data from the FWD testing implied that structural damage was present. The amount of damage present ranged from 0.2 to 2.61 in. of equivalent asphaltic concrete thickness. The full report is available online at https://www.ltrc.lsu.edu/pdf/2019/FR_608.pdf
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