Although cementitious stabilization of soils offers great advantages, such as the beneficial use of on-site inferior materials and waste by-products (fly ash, kiln dust), the approach also causes material shrinkage and subsequent cracking, which limit its widespread use. This study is investigating an innovative approach that combines the self-healing effects of bacterial spores with a method of mixing the material that involves sequential hydration. The use of bacterial microcapsules has been shown to encourage self-healing of cracking in cementitious materials. Sequential hydration is an approach in which less than optimal moisture is first added to a mix for partial hydration. The partially hydrated mixture develops initial strength but exhibits low shrinkage and cracking. With a second addition of moisture, the mixture develops higher strength but also less final shrinkage strain and stress. Mixes containing bacterial microcapsules that enhance self-healing are expected to benefit immensely from sequential hydration, and that combination may produce a novel process for developing cementitious stabilization of soils with high strength and low shrinkage cracking.
Principal Investigator: Balasingam Muhunthan, Civil and Environmental Engineering, WSU
Sponsors: TriDurLE and WSDOT
Scheduled completion: September 2023