Annex 3C: Guidelines for Concrete Pavement 469 The drainage coefficient, Cd, is the factor that accounts for the drainage characteristics of the C subgrade. A value of 1.0 for drainage coefficient d represents a material with good drainage characteristics (e,g., a sandy material). Other soils, with less than ideal drainage characteristics, will have drainage coefficients that are less than 1.0. The load transfer, J, is a factor that is used to account for the ability of pavement to transfer a load from one J PCC slab to another across the slab joints. Any rigid pavements have dowel bars at the joints are typically designed with a J value of 3.2. The concrete modulus of elasticity, Ec, is derived from the stress-strain curve as taken from the elastic region. The modulus of elasticity is also known as EC Young’s modulus. Typical values of Ec for Portland cement concrete are between 3 and 7 million psi (20.7 and 48.3 GPa). The modulus of subgrade reaction, k, depends upon K several factors including the moisture content and density of the soil. As most agencies do not perform testing to measure the k value of the soil, a more common parameter (CBR) is correlated with it.