Highly Ductile and Durable Double-network based Cementation - D3 Cement

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

The goal of the project is to explore a non-conventional cementation technique using highly ductile and durable double-network materials, namely "D3 cement." This research mainly addresses two challenging issues - brittleness and non-durability - with current chemically or biologically cemented soil. Specifically, many mineral precipitation-treated soils can be stiff, but break easily at low strains. Hydrogel-treated bio-cemented soil has been found more ductile upon drying, but loses its strength when exposed to water, as the large volume expansion of the water-absorbing hydrophilic polymer network breaks the bonding between the soil particles. The D3 cement has broad potential applications in geotechnical, civil, environmental and petroleum fields, including dust control, infrastructure construction, and liquefaction mitigation, with potentially millions of dollars of cost savings. This research will also create a large data set rich in new knowledge on fundamental bio-inorganic-organic-soil interface interactions, and the relationship with their mechanical properties (strength, stiffness, ductility). Diverse education and outreach activities will promote K-12 and public education and Cross-disciplinary Graduate Workshop for the teams from the PI's Materials Lab and the collaborator's Biogeotech Lab. In this cross-disciplinary project, the objective is to overcome the limitations of fracture at low strains and non-durability by developing a novel cement that is 1) ductile and stiff and 2) less susceptible to water-induced soil strength loss, by uniquely extending concepts of material science to bio-cementation. The approach is to design and develop a hybrid cementing materials which can simultaneously form an organic-and-inorganic, interpenetrating double network in the soil and strongly bind the soil particles, possessing novel self-healing ability via organic-inorganic-soil reformable bonding. The performance of the new composite material will be examined with controls over the material composition, morphology, and hierarchical structures. This research, if successful, will yield a high-performance bio-based geological material. The work will be done in collaboration with researchers at the NSF-funded Center for Bio-mediated and Bio-inspired Geotechnics at Arizona State University.