Advanced Structures & Composites Center

Published: 2020

Publication Name: Geo-Congress 2020

Publication URL: https://ascelibrary.org/doi/abs/10.1061/9780784482780.055

Abstract:

Soil carbonation—the process of introducing carbon dioxide gas and an alkali mineral in soil—is a potential alternative to chemically strengthen subgrade materials by cementing the soil matrix. In this study lime (alkali source) was mixed with non-plastic silty sand to investigate the influence of fine content (0, 20, 50%), lime content (1 and 10%), and the carbonation period (3 and 24 hours) on the unconfined compressive strength of elemental soil specimens. Thermogravimetric analyses on select specimens verified that changes in unconfined compressive strength arose due to the carbonation process. Unconfined strengths increased with fine content, lime content, and carbonation period. The fine content and lime dosage had a greater influence on the ultimate strength than the carbonation period, indicating the chemical reaction occurred quickly at the elemental scale. Unconfined strengths up to 1,000 kPa were achieved for silty sand with a 50% fine content, 10% lime, and carbonation period of 24 hours. Approximately 70% of this strength was achieved for a carbonation period of 3 hours for the same soil and lime content. Unconfined strengths no greater than 250 kPa were achieved for specimens tested with lower fine contents.