Strength Criteria Used to Evaluate the State of a Flexible Road Pavement Construction

Abstract

In recent years due to the increased traffic intensity of heavy weight vehicles (HWV) and inadequate funding the scope of pavement repair and strengthening work including quality of such work has been gradually declining and the state of road pavements has been worsening. Due to their inadequate features (width and evenness of a pavement, strength of a pavement construction, etc.) the roads of Lithuania cannot withstand rapidly increasing loads of HWV. Up until now there is no reliable methodology that would allow to determine the extent of destroying impact of HWV on a road pavement and its construction. By means of similar new methodologies (ODN 218.046-01, VSN 46-83, VSN 543-87 and VSN 52-89) that were previously applied in Lithuania it is not possible to make reliable predictions of changes in the strength of a road pavement construction (RPC) and of the duration of its real service life as well as to evaluate the increase of fatigue failures in its asphalt concrete layers. This article illustrates that the state of RPC could be evaluated by means of elastic deflection of RPC. In addition it reveals the impact of seasonal peculiarities of traffic and of RPC ultimate strength on the permissible traffic intensity of design load within a year in the presence of conditions that are peculiar to Lithuania. In analysing the duration of service life of asphalt concrete layers the evaluation criteria should include not only changes in material strength during its exploitation time but the coefficient of remaining fatigue, evaluating possible changes in the state of asphalt concrete layer in different seasons of the year, as well.