A: BLENDING THE IN SITU SOIL WITH CHEMICAL ADDITIVES, AND THEN COMPACTING THE MIXTURE AT THE PROPER MOISTURE CONTENT FOR STRENGTH AND STABILITY.

A: PORTLAND CEMENT (INCLUDING CEMENT KILN DUST) LIME (INCLUDING QUICKLIME, HYDRATED LIME AND LIME KILN DUST) TYPE "C" FLYASH, AND BITUMINOUS PRODUCTS. THE APPROPRIATE ADDITIVE WILL BE BASED ON THE SPECIFIC SOIL TYPE.

A: GEOTECHNICAL REPORTS FROM THE PROJECT SHOULD BE CONSULTED.  THE GEOTECHNICAL REPORT WILL OFTEN SUGGEST THE RECOMMENDED ADDITIVE.  THE TABLE BELOW PROVIDES GENERAL GUIDELINES. IT IS IMPORTANT TO NOTE THAT MORE THAN ONE CHEMICAL ADDITIVE MAY BE SUITABLE FOR ONE SOIL TYPE.

A: APPLICATION RATES VARY DEPENDING ON THE ADDITIVE, SOIL TYPE AND CONDITION AND DESIRED RESULT (STABILIZATION OR MODIFICATION).  GENERALLY, A GEOTECHNICAL ENGINEER SHOULD BE CONSULTED WHEN SOIL STABILIZATION IS THE GOAL.  LOCAL EXPERIENCE IS OFTEN THE BEST GUIDE WHEN SOIL DRYING AND SOIL MODIFICATION IS THE GOAL.

A: THIS SHOULD BE DONE WITH A SELF PROPELLED ROTARY MIXER.  MOST MACHINES ON THE MARKET ARE CAPABLE OF MIXING TO A DEPTH OF AT LEAST 16 INCHES.  DISKS AND HARROWS SHOULD BE AVOIDED DUE TO INCOMPLETE MIXING.

A: THE TYPICAL DEPTH IS 12", BUT STANDARD PRACTICES MAY VARY FROM REGION TO REGION.  IN SOME CASES, THE DEPTH OF RUTTING OR UNSTABLE SOIL CAN LEAD TO DEEPER LAYERS.  THE PAVEMENT DESIGN MAY ALSO DETERMINE THE REQUIRED DEPTH OF STABILIZATION.AS WELL AS RECOMMENDATIONS FROM A GEOTECHNICAL CONSULTANT FAMILIAR WITH THE SPECIFIC CONDITIONS.

A: A MINIMUM OF 24 HOURS AFTER FINAL COMPACTION.  MANY SPECIFICATIONS REQUIRE 7 DAYS WHEN SOIL STABILIZATION IS THE GOAL, BUT SHORTER PERIODS (48 - 72 HOURS) ARE OFTEN SPECIFIED.  WHEN SOIL DRYING AND MODIFICATION IS THE GOAL, 24 HOURS IS GENERALLY ADEQUATE.

A: WHEN STABILIZATION IS THE GOAL, MOST STATE AGENCIES REQUIRE SURFACE CURING WITH WATER, OIL, BLENDED ASPHALT EMULSIONS OR ANOTHER CHEMICAL CURE TYPICALLY USED IN CONCRETE WORK. CURING IS TYPICALLY NOT NECESSARY WHEN SOIL MODIFICATION (SOIL DRYING, SOIL CONDITIONING) IS THE GOAL.

A: YES. SOIL STABILIZATION PERMANENTLY INCREASES THE SOIL STRENGTH AND CAN BE INCORPORATED INTO THE STRUCTURAL DESIGN OF THE PAVEMENT. THE PRIMARY GOALS OF SOIL DRYING AND SOIL MODIFICATION ARE TO LOWER THE SOIL MOISTURE CONTENT AND REDUCE THE SOIL PLASTICITY TO AID IN CONSTRUCTION.

A: YES. THESE TYPE OF PROJECTS ARE WHERE SOIL DRYING/MODIFICATION IS MOST BENEFICIAL SIMPLY REMOVE AS MUCH STANDING WATER AS POSSIBLE. ALL OF THE DRY CHEMICAL ADDITIVES NEED WATER TO REACT PROPERLY, JUST NOT TOO MUCH.

A: YES. BESIDES THE COSTS OF HAULING MATERIALS ON AND OFF SITE, THERE ARE USUALLY GEOTEXTILE FABRICS ASSOCIATED WITH THE SPECIFIC AGGREGATE REQUIRED TO STABILIZE THE SITE. CONSIDERING THE LABOR, EQUIPMENT AND MATERIALS NECESSARY FOR AN UNDERCUT SITUATION, A CHEMICALLY STABILIZED SUBGRADE WILL NORMALLY PROVIDE A SIGNIFICANT SAVINGS OVER THIS METHOD, DEPENDING ON THE SIZE OF THE TREATMENT AREA.

A: NO. AGRICULTURAL LIME (AG LIME) IS NOT EFFECTIVE FOR SOIL STABILIZATION. TYPICALLY, AG LIME IS COMPOSED OF FINELY GROUND LIMESTONE AND DOES NOT POSSESS THE NECESSARY CHEMICAL COMPONENTS FOR SOIL MODIFICATION OR STABILIZATION.

A: IF A SITE IS TRULY STABILIZED AS OPPOSED TO MODIFIED, WET WEATHER WILL HAVE VIRTUALLY NO EFFECT ON THE FINAL CONDITION OF THE SITE. IN FACT MANY OWNERS STABILIZE THEIR SITES TO HELP PROTECT AGAINST CONSTRUCTION AND WEATHER DAMAGE OVER A WINTER SEASON PRIOR TO FINAL SURFACING.