The development of new admixtures for concrete is normally an experimental endeavor in that the molecular scaffolds of existing admixtures are modified and tested. This approach is time consuming, incremental and typically expensive. Alternatively, a computer-aided molecular design (CAMD) approach is proposed that uses the Signature molecular descriptor. CAMD is the application of computer-implemented algorithms that are utilized to design molecules with optimally predicted properties such that they can be tested and evaluated for efficacy. The property of interest here is the surface tension of compounds in aqueous solutions as this property is related to shrinkage in concrete. In particular, we have chosen two classes of compounds, amines and glycol ethers, as they present opportunities for use as shrinkage reducing admixtures (SRAs). By evaluating the initial surface tension reduction in these compounds in solution with water, a number of structure-property conjectures associated with the effect of these compounds were developed. From these conjectures, 14 compounds were identified and utilized as a training set for the CAMD of new compounds. After creating and refining a quantitative structure-property relationship (QSPR) model for surface tension reduction, a structure enumeration algorithm was employed to generate structures outside of the original training set that have optimally predicted properties. In work, the CAMD approach is introduced as well as the identification of new compounds with the greatest predicted impact on the surface tension reduction in water. Furthermore, the surface tension reduction for the newly identified compounds was experimentally evaluated.