Cement and concrete are regarded as the primary construction materials for use in the new millennium and Portland cement is by far one of the most extensively used materials on earth today. The construction of increasingly tall, more intricate and ornate structures require cementitious materials to be stronger and more flexible and this is generally achieved by inclusion of chemical additives into cementitious materials. These can include fillers to give improved strength, accelerators to decrease reaction time and polymer-based materials to make the final material less brittle. This book seeks to explore the use of polymers as additives to cementitious materials.