Rice Husk Ash Stabilization of Reclaimed Asphalt Pavement Using Cement As Additive

Abstract

A laboratory evaluation of the characteristics of rice hush ash (RHA) stabilized reclaimed asphalt pavements (RAP) subjected to British Standard light [BSL (standard Proctor)] compactive effort to determine the compaction characteristics and California bearing ratio (CBR) values was carried out. Test results show that the properties of RAP improved when treated with RHA, using up to 2% cement additive. The particle size grading improved from 100% coarse aggregates for 100% RAP to 10 - 90% coarse aggregate with 10 - 90% fines for the various RAP + RHA mixtures containing up to 2% cement. The CBR values also increased from 8 and 14% for the unsoaked and soaked conditions, respectively, for 100% RAP content to 73 and 79% (soaked condition) for 89.25% RAP in the RAP/RHA mix proportions with 1.5% cement/89% RAP content in the RAP/RHA mix proportions with 2% cement content, with corresponding unsoaked CBR values of 28 and 26%, respectively. Generally, soaked samples recorded higher CBR values than unsoaked samples. The RHA stabilized RAP mix proportions with 89.25% RAP/1.5% cement content, and 89% RAP/2% cement content with CBR values of 73 and 79% (soaked for 24 hours) can be used as subbase or subgrade materials in road construction.