Combinations of chemical admixtures have been developed that allow the placement and curing of concrete at temperatures below freezing without the need for thermal protection. The admixture formulations used in `antifreeze concrete¿ self-protect against freezing to a minimum internal concrete temperature of °C. As part of the broader title Extending the Season for Concrete Construction and Repair, two research phases have been completed by way of sponsorship through the Transportation Pooled-Fund (TPF) program. The final report for Phase I - Establishing the Technology, designation TPF-5(003), was released in February 2004. Supported by 10 northern State Departments of Transportation (DOTs), this phase demonstrated the feasibility and practicality of using antifreeze admixtures in concrete, and devised the tools needed to design, mix, place, and cure concrete in below-freezing weather. Antifreeze formulations were used at five field sites during winter seasons. ASTM C 1622, Standard Specification for cold-Weather Admixture Systems, approved in 2005. The results from Phase II - Defining Engineering Parameters, designated as TPF-5(075), were released in April 2006. Phase II, supported by 9 State DOTs, defined the effect of the Phase I antifreeze formulations on the freeze-thaw durability of concrete. Exposed to freeze-thaw cycling, the durability increased with admixture dosage, except at higher dosages, where durability declined. These findings suggested a limit to the maximum amount of admixture that may be added into concrete. Both reports are available at http://www.crrel.usace.army.mil/ Currently, concrete made according to the Phase I recommendations is capable of resisting freezing to an internal concrete temperature of at least ¿5 °C. However, experience has shown that this much protection is not always necessary, that is, a ¿5 °C concrete can be over-designed for many applications, and this may be more costly than is necessary. External to the pooled-fund program, three field studies were conducted in Alaska during 2007 and 2008. The field studies clearly demonstrated the need for development of tools and guidance on the usage of antifreeze concrete mixes. These tools are needed for designing the optimum admixture dosage for a given job site with varying weather conditions at any job location and form the basis for the Phase III investigation.

The primary objective of this proposed effort is to develop tools and guidance to specify dosage levels of admixtures used in antifreeze concrete to correspond with the varying cold weather conditions experienced at any job location.

The study consists of three primary components. A review of the data collected from previous field sites will be used to identify the required inputs needed in designing antifreeze concrete mixes. This information will be useful in developing guidance to design admixture dosages for concrete to meet the varying job site environmental conditions. A third, currently optional component of the study, will develop a computer-based design tool to allow the user to evaluate a full range of admixture dosages to fit the anticipated weather conditions at a given job location.

Research study for Phase III is in Progress.