Concrete is the most important material in the civil engineering. The concrete compressive strength is a non-linear function of the concrete age and some constituents. These constituents include cement, blast furnace slag, fly ash, superplasticizer, coarse aggregate and fine aggregate. The superplasticizers are among elements which are important in increasing the concrete compressive strength and we are going to analyze here using the tree-classification decision algorithm. The decision trees, usually, are used in classification of a bunch of data. J48 is one of the most favoured ones. The decision trees are developed using information entropy on a collection of training data. J48 is a recursive algorithm that combines the remaining of the following data sets and continues normalizing the output data using the separation process until a uniform classification result obtains. This article evaluates the superplasticizer effect on the concrete compressive strength using the tree-classification decision algorithm.