![]() Finally, regression equat ions for predicting the layer coefficients of base layers were developed for the selected aggregates and their applications in pavement design were illustrated through design examples. Furthermore, the effects of gradation, moisture content, drainage condition, and different stabilizing agents on layer coefficients were investigated. Different combination of materials & thicknesses may result in the same SN ii. Layer coefficient values (a2) for the base course layer were determined for each combination of three different MR values of asphalt concrete (AC) layer, three different AC layer thicknesses, and four different base layer thicknesses. Topic 7 AASHTO Flexible Pavement Design 1.3.4 Design Notes i. The variation in MR values due to these effects was examined and the material parameters kl and k2 required by the AASHTO design equation were evaluated The AASHTO flexible pavement design methodology uses layer coefficients to relate the structural design of the pavement with its performance. PAVEXpress is a free online tool to create pavement designs using key engineering inputs, based on the AASHTO 19 supplement pavement design process. Three different industrial by-products (Class C fly ash, Fluidized bed ash, and Cement-kiln-dust) were used for comparison. For the marginal (Meridian) aggregate, the effect of stabilization on the MR values was investigated in terms of different amount of stabilizing agents and different curing periods. A series of laboratory tests was conducted on the RS and the Sawyer aggregates to investigate the effect of testing procedure, gradation, moisture content, and drainage condition on the MR values. (7.12) can be used for the design of a flexible pavement by limiting the value of A, the deformation, to a desired value. Based on the Los Angeles abrasion values, the RS and the Sawyer aggregates are considered good quality aggregates, whereas the Meridian is considered a marginal aggregate. Today it is widely accepted that load equivalency factor is. Three coarse aggregates, namely, Richard Spur (RS), Sawyer, and Meridian, that are commonly used as subbase/base of roadway pavements in Oklahoma were selected. 1993 AASHTO Guide, is not enough to represent the complex failure modes of flexible pavements. A comprehensive study involving laboratory testing of resilient moduli (MR) of aggregate materials, determination of layer coefficients, and their application in AASHTO flexible pavement design was conducted.
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