Abstract
Granular activated carbon (GAC) particles impregnated with antimicrobial metals were incorporated into cementitious materials for the express purpose of inhibiting biogenic concrete corrosion. We report herein the influence of such metal-laden GAC particles on the hydration of cement mortars when substituted for fine aggregate, as well as the dispersion of metal in the cured matrix. Isothermal calorimetry was utilized to study the influence of GAC without and with copper and/or cobalt on select hydration characteristics of ordinary portland cement (OPC) mortars. When 1% of the fine aggregate mass was replaced with GAC particles of similar size, total evolved heat in all formulations was similar, regardless of GAC pretreatment. However, as the substitution approached 10% of the fine aggregate mass, metal-laden GAC formulations imparted delays in heat liberation and lowered heat fluxes. Results also substantiate that metal-laden GAC particles participate in the enhanced uptake of the calcium that is normally liberated during cement mixing and that the water delivered with GAC particles is not readily available during the first 142 h of curing. Electron microprobe analysis (EMPA) elucidated that copper and cobalt were homogenously distributed throughout the cement paste with metal-laden GAC, with these metals concentrations localized in a 50–100 μm region surrounding the GAC particles. Compressive strengths were not affected by the presence of metal-impregnated GAC in the concentration ranges tested and reported herein.
| Original language | English |
|---|---|
| Article number | 103588 |
| Journal | Cement and Concrete Composites |
| Volume | 110 |
| Early online date | 12 Mar 2020 |
| DOIs | |
| Publication status | Published - 1 Jul 2020 |
Funding
The authors would like to thank the Bureau of Reclamation (USBR-Denver) for its help with conducting the calorimetry tests. Dr. Aaron Bell in the Department of Geological Sciences at the University of Colorado Boulder is also gratefully acknowledged for his assistance with EMPA. This research was supported by the Mexican National Council for Science and Technology ( CONACYT ) through Fellowship No. 103259 and the Department of Civil, Environmental & Architectural Engineering at the University of Colorado Boulder through a Doctoral Dissertation Completion Fellowship. This work represents the views of the authors and not necessarily those of the sponsors.
Keywords
- Activated carbon
- Antimicrobial mortar
- Cement hydration
- Electron microprobe analysis
- Heavy metals
- Isothermal calorimetry
ASJC Scopus subject areas
- Building and Construction
- General Materials Science