Testing and analysis of LWT and SCB properties of asphaltic concrete mixtures : tech summary.

PDFTech Reporthttp://www.ltrc.lsu.edu/pdf/2016/ts_536.pdfLTRC Report 536SIO No. 30000220 / LTRC Project No. 11-3BAsphalt concreteHot mix paving mixturesLouisianaLouisiana Transportation Research CenterCooper, Samuel B.Louisiana Transportation Research CenterUS Transportation CollectionFor pavement to perform well in the fi eld, a balance of both rut and crack resistance in response to the traffi c loadsand environment conditions is required. Controlling volumetric properties of a hot mix asphalt (HMA) mixture is notenough to ensure good pavement performance because pavements often do not perform as they are designed. DOTDspecifi cations were designed to target rutting as the major distress impacting Louisiana roadways. However, an adverseeff ect of that specifi cation was the production of \ue2\u20ac\u153dry\ue2\u20ac? mixtures. The reduced asphalt content in the mixtures resulted inquestionable durability of the roadway. A possible solution would be the development of laboratory test procedures toevaluate the as-built pavement-qualities to predict the pavement performance and life. In so doing, numerous agenciesaround the United States are incorporating mechanical tests to evaluate the rutting potential, cracking potential, andmoisture susceptibility of HMA mixtures. Recent DOTD specifi cation changes were implemented and evaluated usingsemi-circular bending (SCB) and loaded wheel tracking (LWT) tests. The results of thesespecifi cations were used to implement balanced mixture design practices. This studyevaluated the use of the LWT and SCB tests as end result parameters to indicate thestability and durability of HMA mixtures. As part of this study, an attempt was madeto develop a simplifi ed and reasonable SCB test procedure so that the commonly usedMarshall Load frame device would be adapted for plant and district laboratory testing