Effect of the chemical composition of compaction water on the performance of soil subgrades and embankments

The Texas Department of Transportation (TxDOT) wants to employ the use of other water sources (alternative water) besides potable drinking water for those construction projects that use large amounts of water. This is due to increasing cost of drinking water treatment and, therefore, a consequent scarcity of potable water for construction purposes. The sometimes prohibitive cost of hauling water from remote areas to certain construction sites, and more importantly, issues related to performance are also part of the reason for this research effort.

The research deals mainly with the investigation of the potential effects of the chemical composition of compaction water on the performance of soil subgrades and embankments, with an emphasis on the effects of sodium. Shaikh et al. (1988) indicate that the primary factor that influences the erodibility of unsaturated compacted clays is the soil pore-water chemistry.

A comprehensive laboratory test program was carried out to ascertain the possible effects that the chemical composition of compaction water could have on engineered soils. Test results from the project would help in developing predictive models to serve as a framework for a preliminary feasibility evaluation, and selection of a particular alternative water source for use among candidate sources. Similarly, appropriate blending ratios could be determined for those water sources to meet design specifications.

Varied results have been obtained that would lead to various conclusions. It was observed that even the worst sources of alternative water would have no significant effect on engineered soils.