The effect of compaction degree and binder content on performance properties of asphalt mixtures

The effect of compaction degree and binder content on performance properties of asphalt mixtures of an asphalt concrete type for wearing and binder courses are described in the paper. Measurements of stiffness modulus by two-point bending test on trapezoidal shaped specimens, fatigue characteristics, and resistance against frost cracking by thermal stress restrained specimen test have been performed on selected asphalt mixtures. The main aim of the experimental part was to determine to what extent the performance properties of the individual mixtures will be affected when decreasing the compaction degree by 3% in comparison to the optimal design, i.e. from 100% to 97% degree of compaction. This decrease simulates incomplete degree of compaction of courses during pavement construction, which is common and accepted during acceptance tests and it is in accordance with the Czech regulations. Then, the decreased dosage of binder content by 0.5% is simulated, which is the boundary parameter for lowering the binder content within the acceptance test. The results of performance testing have been affected by lower compaction degree and lower binder content have been used as course parameters and integrated into a mathematical model of a commonly used pavement construction, which is presented by a multi-layered linear elastic model based on the use of Burmister‘s equations. The outcome of the paper is a description of the effect of lower degree of compaction and lower binder dosage on the lifetime of a pavement construction.