The broader impact/commercial potential of this I-Corps project will be found in civil engineering infrastructure development projects where construction is undertaken in areas affected by expansive soils, i.e. soils that shrink and swell in response to changes soil moisture level. Such shrink/swell activity in foundation soils is a leading cause of structural damage to roadways and other infrastructure systems built upon them. In the United States Texas, Colorado, Louisiana, Arkansas, Mississippi, Alabama, Nebraska, North Dakota and South Dakota are among the states with major problems due to presence of expansive soil. Expansive soils have reportedly caused problems in other parts of the world as well. Traditionally, lime and Portland cement have been used to stabilize such expansive soils. However, these traditional stabilizers cannot be used in all soil conditions. In such situations, the only viable solution is to remove the native soil and replace it with better quality materials. The proposed I-Corps technology involves a sustainable soil stabilizer that overcomes many of the limitations found in the traditional stabilizers. It provides a more economical alternative in projects where remove-and-replace strategy is currently used.
This I-Corps project explores opportunities for commercialization of a novel soil stabilizer which uses an inorganic compound known as geopolymer as the key ingredient. Geopolymers are synthesized using abundantly available natural materials and/or industrial by-products such as fly ash and ground blast furnace slag. Unlike traditional soil stabilizers (viz. hydrated lime and Portland cement) which require vast amounts of energy during production, geopolymers are synthesized at or near ambient temperatures. Accordingly, the new stabilizer represents a more sustainable alternative to traditional soil stabilizers. Extensive laboratory testing and microstructural studies conducted during the product development phase demonstrate that the new stabilizer can achieve more than 90% reduction in shrink/swell potential. The experimental data also confirm that the geopolymer-based stabilizer can be used effectively to overcome a number of significant limitations that exist in the traditional stabilizers, such as inability to treat sulfate-bearing soils. Traditional lime stabilization requires a waiting period of 4-7 days for the stabilizing reactions to take place; this causes interruption in work flow and delay in construction. In such situations, the new stabilizer can be used to treat the native soil and improve its engineering properties and thus eliminate need for expensive remove-and-replace operations.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
