Technical and environmental assessment for soil stabilization using coal ash

In most Latin American countries, low-volume roads are composed of unpaved roads; this is considered a problem of economic, social and environmental interest. There are different stabilization alternatives for this type of roads with traditional materials, i.e., Portland cement (OPC) and lime (L), both of which have a high environmental impact due to anthropogenic CO2 emissions. This paper presents the results of the environmental assessment of an industrial residue Coal Ash (CA) with pozzolanic characteristics. The residue was alkaline activated with Ca(OH)2 from commercial lime (L). The binary system (CA+L) is called (CLM) and forms a material with cementing properties, and when it is mixed with soil, it increases the capacity to support loads. The CLM as a soil stabilizer is proposed along with the modification of some construction processes associated with lime technology and Portland cement. Finally, a technical and environmental comparison is made for conventional stabilizers and the binary system CLM. The results showed that stabilization of a silty soil with CLM can achieve a reduction of 58% and 75% in CO2 emissions when compared with L and OPC, respectively.