Why do I need polymer in my GFRC?

Article courtesy of Smooth-On, Inc.

First, an understanding of cement hydration relative to GFRC is needed. GFRC is a thin-section Portland cement-based composite with low water/cement ratio. This makes the composite very susceptible to excessive evaporation of the water required for proper hydration and cure. Therefore, it was recommended in the early days of GFRC that a 7 day wet cure be done to achieve maximum matrix strengths. Forton® VF-774 was the first polymer to prove through independent testing that it can eliminate the need for a 7 day wet cure and still achieve maximum matrix strength. Most other polymers marketed to GFRC lack independent test data showing they can eliminate the 7 day wet cure. Another very important reason for polymer is the maintenance of long term durability. Forton® VF-774 is the only polymer on the market with independent test data showing naturally aged GFRC that maintains its early age Flexural Ultimate strengths and strain to failure.


This FAQ article is offered as a guideline and offers possible solutions to problems encountered during mold making and casting. No warranty is implied and it is up to the end user to determine suitability for any specific application. Always refer to the provided Technical Bulletins (TB) & Safety Data Sheets (SDS) before using any material. A small scale test is suggested to determine suitability of any recommendation before trying on a larger scale for any application.