We are trying to reduce our bid cost by utilizing the excavated limestone as our backfill material. Will there be any issue on this? Since limestone is known to be soluble to water?
The question is too broad to answer. Limestone is an often used building and pavement material, but there is a big difference in types of limestone, and in stability of the different types.
Crushed sedimentary limestone is an excellent material for backfill. In fact, where I work, it is the only high quality material available at a reasonable price. It has excellent properties and compacts well. It is suitable as the base for buildings, roads, railroads, etc... and we use it for all of those applications. Also, we have a high water table (at or just below the surface). Solubility is not an issue - the limestone was mined locally from below the water table, where it has been for a few million years.
According to this reference, limestone and similar material is used for 70% of the crushed stone in the USA.
Limestone runs the range, from excellent to extremely poor.
You have to provide more information.
Local Geotechs, Geologists and trusted contractors should be consulted for specific formations and localities.
Agree with SRE....In my area, it is the primary material used for roadway bases, stabilization, concrete aggregate and general fill using tailings from the cast-off of other uses. Yes, it has a range of quality, but even lower quality calcareous silts can be used effectively when mixed with more competent materials.
Someone or administrator seem able to remove/cook the thread/responses. Bad and shameful practice.
Do not use unprocessed limestone without consultation. The excavated material should be inspected and cleared by a geotechnical engineer, geologist, and/or lab.