Section V, Portland Cement Concrete, and in the previous discussion of 

 preplaced aggregate concrete. In some cases the desired properties can be 

 satisfactorily obtained by using one of the previously described special 

 types of Portland cement. 



b. Mixes . Where grout can be pumped or poured into relatively open 

 joints or voids a mixture of one part cement to typically three or four 

 parts sand is common, with just enough water for satisfactory placement. 

 For very large voids, gravel may also be added. Where the material will be 

 pumped into the ground to raise a settled slab or behind a bulkhead to plug 

 a hole or break, a mixture of clay or silt with about 10 percent cement can 

 sometimes be used. For filling or repairing narrow joints or cracks a neat 

 cement grout consisting of 1 part cement mixed with 1 to 10 parts water to 

 obtain proper consistency, may be appropriate. In some cases the use of an 

 admixture may be justified to enhance certain properties. In such a case 

 care should be taken to ensure the suitability of the admixture for the 

 conditions and materials involved, and that dosage and mixing are correct. 

 Pertinent Corps of Engineers Specifications include CRD C615, CRD C619, CRD 

 C611, and CRD C612. 



c. Placement Methods and Effects . Portland cement grout is usually 

 placed by one of the following methods: 



(1) Dumping or pouring into large voids or onto flat or sloping 

 surfaces; 



(2) free discharge from a hose or tremie trunk, above or under 

 water, into a form or into voids or cavities in rock, masonry, or 

 concrete; 



(3) pressure discharge from a hose or pipe; 



(a) into soil to correct settlement of a slab or light 

 foundation by displacement or "mud jacking," or behind a 

 bulkhead for sealing or patching; or 



(b) into cracks or joints in concrete, masonry, or 

 rock; and 



(4) hand placement by pouring or "dry packing." 



Where grout is used to fill joints, cracks or cavities in structural 

 members it will be important to avoid or minimize shrinkage. This will 

 require the best practicable combination of compaction, low water-cement 

 ratio, and possibly the use of an expanding or plasticizing admixture in the 

 grout. If a significant surface area of freshly placed grout is exposed to 

 the air, especially when the grout has a high cement factor, the surface 

 will need to be kept continuously moist for several days if shrinkage cracks 

 are to be avoided. 



If the grout is injected into a confined space, such as immediately 

 behind a bulkhead or into cracks or cavities, caution must be used to avoid 

 building up excessive pressure which could displace or rupture the confining 

 structure. This can be avoided by carefully limiting the injection pressure, 



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