Title:
ARCTEC (Additive Regulated Concrete for Thermally Extreme Conditions): Development of Multi-Parameter Guidance for Freeze-Protection Additive Dosage
Author(s):
Benjamin Watts
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/17/2021
Abstract:
In cold temperatures, fresh concrete can be irreversibly damaged by the formation of ice within the hydrating microstructure before adequate strength has developed. Industry-standard protection measures are frequently laborious, expensive, and time-consuming. The USACE ERDC Cold Regions Research and Engineering Laboratory (CRREL) has developed ARCTEC (Additive Regulated Concrete for Thermally Extreme Conditions) to enable the use of commonly available concrete additives as alternative freeze-protection in cold conditions. ARCTEC builds upon pioneering work performed at CRREL over the last several decades, with the goal of improving the user-friendliness, economy, and utility of the technology. A core component of ARCTEC is guidance to recommend the required dosage of additive for a successful concrete placement. This recommendation depends upon multiple aspects of a placement, including geometry, mixture proportions, ambient temperature, wind, and time of placement. The number of unique cases implied by these parameters precludes physical testing of every possibility, so a transient finite element thermal model was created to simulate the effects of these parameters on the evolving thermal behavior of concrete placed at a range of additive dosages. Inputs for this model were obtained through laboratory characterization of the thermal and mechanical behavior of concrete at multiple curing temperatures and additive dosages. These inputs, when combined with synthetic daily temperature profiles, variable convective boundary conditions, a range of placement geometries and constructions, and maturity-informed success criteria, result in the ability to define the optimal additive dosage over a broad range of possible placement configurations.