Louay N Mohammad

Regression Model for Resilient Modulus of Subgrade Soils

Subgrade soil is an important part in both flexible and rigid pavement structures. AASHTO recommends the use of bulk stress and deviatoric stress models to characterize granular and cohesive soils, respectively. However, these models oversimplify the fundamental behavior of subgrade soils. Being proposed is the use of an octahedral stress-state model to characterize the resilient modulus of different soils. Eight different soils representing major soil types in Louisiana were selected to validate the model and to calibrate the model parameters. Additional analysis was then performed to develop correlations between the model parameters and other soil properties. Three types of correlation were produced: (a) model parameter with soil properties, (b) model parameters with California bearing ratio, and (c) model parameters with unconfined compressive strength. Statistical analysis indicated that the correlation between model parameter and soil properties yielded the best results.

Laboratory and Construction Evaluation of Warm-Mix Asphalt

AbstractWarm mix asphalt (WMA) describes various technologies that allow asphalt mixtures to be produced at lower temperatures as compared with hot mix asphalt (HMA). WMA technologies also offer improvements in workability, cost, and environmental sustainability, such as reduced fuel usage, greenhouse gas emissions, and wear and tear at plants, while enhancing worker health and safety conditions. The objective of this study was to quantify the laboratory performance of field-produced mixtures that utilize WMA technologies and to evaluate the influence of lowering the production temperature on the mixture properties in the field. To achieve this objective, three field projects across Louisiana were selected to provide eight mixtures for the evaluation of WMA technologies. Plant-produced mixtures were sampled and the laboratory performance of WMA mixtures and conventional HMA was evaluated. Further, the characteristics of WMA mixtures were compared with conventional HMA mixtures during production and constr...