### Water/Cement Ratio - an overview | .

This agrees with a water/cement ratio for fly ash concrete of 0.72 and a water/cement + fly ash ratio of 0.58. The difference in regression coefficients between reference and fly ash concrete causes the dependence of the k-value on the water/cement ratio. If the starting point for a k-value determination is a "worst case" approach, then k-values should be determined at water/cement ratios ...