Application of cyclic CBR test for the estimation of resilient modulus in the pavement construction

摘要

In this paper the cyclic CBR test as a reference method in determination of resilient modulus M_r is presented. The main idea of conducted experiments is simplification in testing of natural subsoil and road materials, as well as in pavement laboratory loading test. The article shows results of investigation on cohesive soil, namely sandy clay, commonly problematic soil in Poland. The results of repeated loading triaxial test with bender elements and resonant column test were displayed in order to compare them with cyclic CBR test results. Some empirical correlation between factors obtained from triaxial test or resonant column and cyclic CBR test was introduced here. The behaviour of cyclic loaded soil was also examined in this paper. For better understanding of this phenomenon, shakedown theory was illustrated in the article as well. Shakedown limit was established for repeated loading triaxial test and cCBR test. This paper finishes with some conclusions for the above-mentioned theory.