This study presents the effect of ECOLOPAVI stabilizer on Low Cost Roads (LCR). This study found that a mix of 2% cement and 5% ECOLOPAVI can improve the bearing capacity (CBR) of clayey soil with CBR = 3% up to 49%; similar result can be get by adding 6% to 7% of cement or lime in conventional practices; that means the combination of ECOLOPAVI with cement or lime can be used to reduce the construction cost of roads. This product is presented as an alternative to other conventional stabilizer in use (cement or lime). In this research, ELSYM 5 program is employed to evaluate and compare two pavement structures with natural subgrade soil and with stabilized sub grade. The pavement response show that it is strongly dependent on sub grade layer elastic or resilient modulus; as the depths increase, the stresses, displacement and strains decreased. The results of two pavements (one with sub grade CBR > 3% and another with sub grade CBR > 12%), show that the structure with sub grade CBR > 12% gave low stress, displacement and strains than that with CBR > 3%.