The main challenge with mass concrete structures lies in temperature rise and temperature differentials resulting from the heat of hydration of cementitious materials. Therefore, controlling the heat of hydration in mass concrete structures is important in order to minimize and potentially prevent cracks from forming. In this study, two main novel materials were utilized to study the effect of novel materials on the heat of hydration of paste mixtures. An isothermal calorimeter is used to measure the heat of hydration in concrete mixtures including 1) poly vinyl acetate (PVA) which is a polymer modified material generated from a manufacturing process of paint and 2) barium oxide (BAO) which is a phase changing material. Different percentages of these materials were utilized based on the amount of total cementitious materials in the mixtures. The results were also compared with the heat of hydration of mixtures containing conventional mass concrete mixtures containing cement supplementary materials such as slag and fly ash. It is concluded that the PVA addition (up to 10%) slightly reduces the heat of hydration in concrete mixtures. However, the reduction is insignificant. On the other hand, BAO significantly retarded the heat of hydration and slightly reduced the magnitude of the heat of hydration peak in concrete mixtures, although the 7-day heat of hydration reached the same level as that of the control mixture.