Concrete Grinding Residue Characterization and Influence on Infiltration

Abstract

Concrete grinding residue (CGR) is a slurry byproduct created by concrete pavement maintenance operations. Disposal of CGR slurry is presently regulated on the basis of very minimal information. The least immediate expense is incurred by spreading CGR slurry directly on vegetated roadway ditches and embankments. The direct disposal impacts to environmental quality in terms of soil physical or chemical properties are not known. Five CGR materials from widely dispersed sites in the United States were analyzed for particle size distribution and evaluated with a suite of USEPA physical and chemical analyses. Values found for the parameters examined are not considered harmful. An infiltration column study was also conducted in which two CGRs were mixed at 8 and 25% by weight and also surface applied 2.5 mm deep with two contrasting (relatively fine and coarse textured) soils. With the finer soil, statistically (p < 0.05) significant decrease in infiltration time (increased infiltration rate) was associated with the 25% and surface-applied CGR treatments, compared with the untreated control soil. The results indicate that excessive application of CGR may increase water infiltration into soil in the short-term. This should be kept in mind, but does not appear to be generally detrimental.

Smooth Brome (Bromus inermis Leyss) and Soil Chemical Response to Concrete Grinding Residue Application

“…Application of 25% by weight CGR significantly increased EC of both soils compared with the control and the low, 8% rate ( Table 6). The 94/MN-treated soils exhibited a greater increase in EC compared with the soils treated with 10/CA at respective application rates (Table 6), which was not unexpected due to the 94/MN having nearly double the solution phase EC compared with the 10/ CA (DeSutter et al 2011).…”

“…This concern is supported by the elevated pH of the CGR slurry, which ranged from 11.6 to 12.5 in the DeSutter et al (2011) study and about 12 in the Shanmugam (2004) study. The liming potential of CGR is evidenced by the range of soil pH values measured in non-impacted areas (6.3 to 7.5) and comparing these values with areas that received CGR slurry (7.6 to 9.4; Shanmugam 2004).…”

“…Addition of fly/bottom ash or slag to concrete mixtures would also increase variability between sites (Bertolini et al 2004;Ferreira et al 2003;Mroueh et al 2001;Papayianni and Anastasiou 2010). No polynuclear aromatic hydrocarbons were found, but application of high rates of CGR to soils increased water infiltration (DeSutter et al 2011).…”

“…The two most recent studies are DeSutter et al (2011) and Shanmugam (2004). Both studies highlight the characterization of solution and solid phases of CGR for inorganic and organic constituents.…”

“…Both studies highlight the characterization of solution and solid phases of CGR for inorganic and organic constituents. Concentrations of trace elements were variable across sampling locations in DeSutter et al (2011) and likely depended on the composition of the concrete and quality of water used for grinding. Addition of fly/bottom ash or slag to concrete mixtures would also increase variability between sites (Bertolini et al 2004;Ferreira et al 2003;Mroueh et al 2001;Papayianni and Anastasiou 2010).…”