or by grouting in properly sized increments or lifts £nd allowing adequate 

 setting time between them. Tests for the setting time of grout are described 

 in Corps of Engineers Specification CRD-C614. 



d. Effects of the Environment . Portland cement grout will be affected 

 to varying degrees by the environmental conditions and forces acting on the 

 concrete, masonry or rock with which it is associated. Placed in thin 

 joints or cracks it will have some protection from wave action, abrasion, 

 periodic wetting and drying, and fire but may be vulnerable to water 

 penetration, freeze-thaw cycles, chemical attack and seismic forces. Where 

 used for surface repair, topping or void filling it may be exposed to all 

 these. Most of these environmental forces will be adequately resisted by a 

 grout having an optimum combination of strength, impermeability, entrained 

 air content, and freedom from excessive shrinkage. Where a certain type of 

 exposure is likely to be severe, the added cost of a beneficial proprietary 

 admixture may be warranted. 



e. Functions in Coastal Structures . The many uses of Portland cement 

 grout can be broadly classified as follows: 



(1) In protective structures: 



(a) filling voids in rock revetments; (this may be for 

 improved slope stability, erosion resistance against waves, 

 currents or floating debris, or rat-proofing); 



(b) filling joints in precast block revetments; or 



(c) sealing voids in stone breakwaters to improve wave 

 attenuation. (This should be undertaken very judiciously, 

 lest it cause excessive pressure buildup in the breakwater 

 structure under heavy wave action, or trap and amplify 

 resonant wave energy within the protected water area) . 



(2) In functional structures: 



(a) grouting cyclopean or preplaced aggregate concrete; 



(b) setting steel piling or tieback anchors in rock; and 



(c) filling voids in hollow masonry walls. 



(3) In structural repairs: 



(a) repairing spalled, broken or cracked concrete; 



(b) plugging breaks or holes in steel or concrete bulk- 

 heads; and 



(c) correcting foundation settlement. 



4. Soil Cement . 



a. Description of Soil Cement . Soil cement is a mixture of pulverized 

 soil and measured amounts of Portland cement and water, compacted to a high 



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