Suitability of Remediated PFAS-Affected Soil in Cement Pastes and Mortars

Abstract

Australia and many other parts of the world face issues of contamination in groundwater and soils by per- and poly-fluoroalkyl substances (PFAS). While the pyrolytic treatment of contaminated soils can destroy PFAS, the resulting heat-treated soils currently have limited applications. The purpose of this study was to demonstrate the usefulness of remediated soils in concrete applications. Using heat-treated soil as a fine aggregate, with a composition and particle size distribution similar to that of traditional concrete sands, proved to be a straightforward process. In such situations, complete fine aggregate replacement could be achieved with minimal loss of compressive strength. At high fine aggregate replacement (≥ 60%), a wetting agent was required for maintaining adequate workability. When using the heat-treated soil as a supplementary cementitious material, the initial mineralogy, the temperature of the heat-treatment and the post-treatment storage (i.e., keeping the soil dry) were found to be key factors. For cement mortars where minimal strength loss is desired, up to 15% of cement can be replaced, but up to 45% replacement can be achieved if moderate strengths are acceptable. This study successfully demonstrates that commercially heat-treated remediated soils can serve as supplementary cementitious materials or to replace fine aggregates in concrete applications.

Using Geospatial Data and Random Forest To Predict PFAS Contamination in Fish Tissue in the Columbia River Basin, United States

“…1,46 Cement has also been used for PFAS remediation where contaminated soils and sediments are incorporated into cements and concretes as fine particle aggregates. 47 Glass product industries also use PFAS to protect the glass from weather and pollutants. 46 In addition, PFAS are used on glass as an anti-mist coating to prevent fogging on mirrors, automobile windshields, eyeglasses, and greenhouses.…”

“…A previous study predicting PFAS in groundwater did not find either industry to be important variables in their model . Uses of PFAS in cement manufacturing include being added to reduce cement shrinkage, maintain the cement’s flowing ability without increasing water content, and protect the cement from natural elements and pollutants. , Cement has also been used for PFAS remediation where contaminated soils and sediments are incorporated into cements and concretes as fine particle aggregates . Glass product industries also use PFAS to protect the glass from weather and pollutants .…”