The dimensioning of structural systems in reinforced or prestressed concrete requires knowledge, among other properties, at least of the deformation modulus and compressive strength.

However, concrete may present enough strength, whereas the structure rigidity might not be compatible with minimum required values for the verification of possible deformations. In Brazil, the estimate of deformation modulus is made using the NBR 6118 theoretical equation and internationally, the main theoretical models used are recommended in ACI 318, Eurocode 2, and the fib Model Code.

But the bibliography indicates that there is no confidence in the models proposed. The present study aims to analyze the isolated effect of paste volume on the portland cement concrete deformation modulus. The results of the study indicate a significant influence of paste volume on the module value and, because a reduction in the amount of paste volume occurs, the concrete deformation modulus increases for all ages.

The lack of consistency is also observed between experimental values and those obtained by theoretical equations, suggesting independency of the two magnitudes, compressive strength, and deformation modulus.

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