Urban soils that contain materials derived from demolition undergo carbonation as a consequence of a reaction between Ca derived from cement and concrete, and carbonate ultimately derived from the atmosphere. Estimated rates of CaCO3 accumulation are equivalent to the removal of 150T CO2 ha-1 yr-1. Although this process has benefits for carbon capture, the formation of CaCO3 within the soil potentially affects the geotechnical properties. Trial pits at a number of locations have consistently yielded CaCO3 contents of 20 wt% from 0-1m depth. Carbonate has formed in intergranular space within the soil, possibly with improvements in strength but also with changes in permeability that may affect through drainage. This paper investigates the limits to CaCO3 formation imposed by soil porosity for a number of artificial soils: 'well sorted sand or gravel', 'sand and grave, mixed', 'silt' and 'clay'. Calculated values for CaCO3 for the various soil types are used to determine limits to CaCO3 formation within the first 1 m of sediments at the Science Central Site in Newcastle upon Tyne, UK, using information derived from five trial pits within made ground.
|Title of host publication||From fundamentals to applications in geotechnics|
|Subtitle of host publication||proceedings of the 15th Pan-American Conference on Soil Mechanics and Geotechnical Engineering, 15-18 November 2015, Buenos Aires, Argentina|
|Editors||Diego Manzanal, Alejo O. Sfriso|
|Place of Publication||Amsterdam|
|Number of pages||7|
|Publication status||Published - 11 Dec 2015|