Silicate grouts

Silicate [12627-13-3] Silicate adhesives Silicate esters Silicate grouts Silicate minerals Silicates... 

Silicate Grouts. Sodium silicate [1344-09-8] h.3.s been most commonly used in the United States. Its properties include specific gravity, 1.40 viscosity, 206 mPa-s(=cP) at 20°C Si02 Na20 = 3.22. Reaction of sodium silicate solutions with acids, polyvalent cations, such organic compounds as formamide, or their mixtures, can lead to gel formation at rates, which depend on the quantity of acid or other reagent(s) used. 

Joosten method -silicate grouting [SOIL STABILIZATION] (Vol 22)... 

With the exception of sodium silicate grout gelled with a bicarbonate (such as sodium bicarbonate), all chemical grouts subsequently discussed are generally considered to be permanent materials. 

Figure 10.7 (a) Failure lines for grouted and ungrouted granular soils, (b) Drained triaxial test results for silicate grouted coarse and medium sands. (From Ref. 11.15.) (c) Typical stress-strain curve from unconfined compression test on chemically grouted sand, (d) Compression versus time data for creep test on chemically grouted sand, under constant load, (e) Failure time versus percent of unconfined compression failure load. (+) indicates unconfined compression tests, and ( ) indicates triaxial tests with S3 = 25% of Si. 

In Europe, most of the silicate grouts use organic reactants only. One manufacturer (Rhone Poulenc, France) describes his product (called Hardener 600) as a mixture of open chain compound diacid esters. Figures 11.6 and 11.7 show technical and application data from the manufacturer s literature. 

Figure 11.5 Properties of silicate grouts using organic reactants 1) butyl acetate, 2) isopropyl acetate, 3) isobutyl acetate, and 4) ethyl succinate. (From Ref. 5.)...

Figure 11.6 Properties of silicate grouts in European practice. (Courtesy of Rhodia, Inc., New Jersey, USA.)...

Recent studies indicate that, under some conditions of underground water flow and pressure, silicate grouts may exhibit less than total stability. Krizek and Madden [18], after cautioning that their data is based on very high gradients (100) conclude ... 

For the silicate grouted specimens in which most of the grout was eroded, that grout which remained appeared to be concentrated at the contact points between the soil grains. 

Extreme caution is recommended when considering the silicate grouts tested in this program for use in situation where they will be subjected to high gradients. 

If nothing else, this data suggest caution in recommending the use of silicate grouts for waterproofing and seepage control. 

More recently details of the creep phenomenon in silicate-grouted soils were reported (see Appendix E and Refs. [5, 8], and [2] of this chapter). Some of the relationships between strength and times are shown in Fig. 11.11. 

Figure 11.11 (a) Creep endurance limit for silicate grout, (b) Unconfined... 

Silicate grouts, depending upon grout and catalyst concentrations, may take from several days to as much as 4 weeks to reach maximum strength. Creep studies should be correlated to specific field loading schedules in order to give realistic results. 

Of course, SIROC is not the only domestic silicate grout in use. GELOC is proprietary formulation using esters as catalysts. Data regarding strength and gel time control is similar to those shown in Figs. 11.5, 11.6,... 

Silicates are soluble because the sodium oxide (Na02) which is basic, keeps the pH at a level where silica (Si02) can be dissolved. If the pH is neutralized or lowered, the solubility of the silica is reduced, and it gels or polymerizes. Most silicate grouts depend upon such reactions. However, silicates can also react with salts such as calcium chloride to produce insoluble metal silicates or gels. 

VISCOSITY VERSUS TEMPERATURE oloy, ACRYLAMIDE GROUT A10% AC-400 GROUT 0.S /d TEA, 0.5% AP, 300 ppm KFe 50% SILICATE GROUT 5% FORMAMIOE 5% ETHYL ACETATE 1 j ... 

The strength of sands grouted with Siprogel is similar to that of silicate grouted sands. However, the gel is sensitive to wet-dry cycles and absorbs water readily if submerged and unsupported. 

R.H. Borden, Time-Dependent Strength and Stress-Strain Behavior of Silicate-Grouted Sand," Ph.D. Dissertation, Department of Civil Engineering, Northwestern University, Evanston, Illinois. 

Alaa Ata and C. Vipulanandan, Cohesive and Adhesive Properties of Silicate Grout on Grouted Soil Behavior," Journal of Geotechnical and Environmental Engineering, January 1998, pp 38-52, ASCE, Reston, VA. 

C. Vipulanandan and Alaa Ata, "Cyclic and Damping Properties of Silicate-Grouted Sand," Journal of Geotechnical and Environmental Engineering, July 2000, pp 650-656, ASCE Reston, VA. 

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