ORIGINAL PAPER Correlation of California Bearing Ratio (CBR) Value with Soil Properties of Road Subgrade Soil Valentine Yato Katte . Souleyman Moupe Mfoyet . Bertille Manefouet . Armand Sylvain Ludovic Wouatong . Lawrence Aleh Bezeng Received: 20 December 2017 / Accepted: 12 June 2018 Ó Springer International Publishing AG, part of Springer Nature 2018 Abstract The California Bearing Ratio (CBR) is the most utilised parameter for dimensioning flexible pavements in tropical countries. Often this test is expensive, laborious and time consuming, and to overcome this, some regression analysis (single and multiple) was considered between the soil’s index properties (liquid limit-LL, Plastic limit-PL and Plasticity index-PI), compaction characteristics (max- imum dry density-MDD and optimum moisture con- tent-OMC), percentage of particle sizes (gravel, sand and clay/silt) and CBR. The study was carried out along an ongoing roadway construction project where thirty-three soil samples were collected and trans- ported to the laboratory for analysis. Routine geotech- nical tests were carried out and thereafter correlation and regression analysis were run on the obtained results to assess the relationship between these index properties, compaction characteristics and the exper- imental CBR obtained. The results of this analysis showed relatively fair coefficients of determination of R 2 = 0.772 between CBR and MDD using single linear regression analysis and R 2 = 0.841 between CBR and all the parameters using multiple linear regression analysis (MLRA). Though the MLRA improved the R 2 from 0.772 to 0.841, the inclusion of additional properties results in a marginal increase of R 2 indicative of weak correlators of CBR hence practically not cost effective for pavement design . Keywords CBR  Flexible pavement  Soil index properties  Compaction characteristics  Percentage of particle sizes  SLRA  MLRA  Pearson’s coefficient R 2  Cost effective 1 Introduction Transportation Infrastructure is a key component for any long term development program for any nation. The development of road network is regarded as an index of economic, social and commercial progress of a particular country. No region or country can flourish/ V. Y. Katte (&) Department of Civil Engineering and Forestry Techniques, HTTTC, The University of Bamenda, P.O. Box 39, Bambili, North West Region, Cameroon e-mail: ykatte@yahoo.com S. M. Mfoyet  B. Manefouet  A. S. L. Wouatong Department of Earth Sciences, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, West Region, Cameroon e-mail: mfoyetsouleyman@gmail.com B. Manefouet e-mail: mceliebertille@yahoo.fr A. S. L. Wouatong e-mail: aslwouat@yahoo.com L. A. Bezeng Bela Company LTD., P.O. Box 1104, Bamenda, North West Region, Cameroon e-mail: bezeng_aleh@yahoo.com 123 Geotech Geol Eng https://doi.org/10.1007/s10706-018-0604-x