13 Jul 2022

Effects of Impure Water Sources on Early-Age Properties of Calcium Sulfoaluminate Cements for Rapid Airfield Damage Recovery

Abstract: In austere environments with limited access to clean water, it is advantageous to use nonpotable water for construction (i.e., mixing water for concrete.) In rapid-response situations such as rapid airfield damage recovery (RADR), the use of calcium sulfoaluminate (CSA) cements is beneficial for expedient pavement repairs because of their rapid strength gain characteristics. However, the hydration products formed by CSA cements are substantially different from those formed by ordinary portland cement and might react differently to impurities that water sources may contain. A laboratory study component investigated the application of various salts and impure sources of mixing water with commercially available CSA cement-based products. A field component studied the application of naturally occurring impure water sources for RADR. Recommendations are made for implementation of impure mixing water for RADR using commercially available flowable fill and concrete products made with CSA cement.

30 Apr 2020

PUBLICATION NOTICE: Effects of Boric Acid and Water Content on Fundamental Properties of Proprietary Magnesium Phosphate Cement (MPC) Products

Abstract: Magnesium phosphate cements (MPCs) have been used for decades in proprietary products for pavement repairs. However, products with high exothermic temperatures have short working times, and research is needed to overcome these unfavorable characteristics. The effects of different boric acid and water contents on the fundamental properties of concrete was investigated through 34 trial batch modifications on the following commercially available MPC products: (1) Premier Magnesia’s PREMag PGDM, (2) BASF Master Builder’s MasterEmaco T545, and (3) CeraTech Inc.’s Pavemend TR. Overall results indicated that the increase of boric acid and water content produced favorable decreased temperatures and increased set times but retardation in the early age development of compressive strength. Modifications in the PREMag PGDM product resulted in poor workability, inaccurate time of setting due to a thixotropic nature, and unacceptable compressive strength loss. The Pavemend TR product was significantly affected by the addition of boric acid resulting in nonrecoverable compressive and bond strength loss, excessive expansions, failure at low freezing and thawing cycles, and unacceptable times of setting for rapid-repair applications. The T545 product showed promising performance with 28-day recovery in compressive, flexural, and bond strengths and minimal differences in other properties when compared to the control mixture.