Specification:Patching spalled concrete

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=GENERAL=

SUMMARY
 This procedure includes guidance on patching spalls and holes in concrete with a cementitious patching material. See Specification:General project guidelines for general project guidelines to be reviewed along with this procedure. These guidelines cover the following sections: Safety Precautions Historic Structures Precautions Submittals Quality Assurance Delivery, Storage and Handling Project/Site Conditions Sequencing and Scheduling</li> General Protection (Surface and Surrounding)</li> </ol> </li> </ol>

QUALITY ASSURANCE
<ol type="A"> Masonry and Concrete Repair: Prepare sample panels of size indicated for each type of masonry material indicated to be patched, rebuilt or replaced. </li> </ol> =PRODUCTS=

MANUFACTURERS
<ol type="A"> Sika Corporation 201 Polito Ave. Lyndhurst, NJ 07071 201/933-8800</li> General Polymers</li> Master Builders</li> </ol>

MATERIALS
<ol type="A"> Concrete Patching Material: One component, early strength, cementitious patching material &quot;SikeTop 222 or 223&quot; (Sika Corporation); &quot;TPM 723&quot; (General Polymers); &quot;Vertipatch&quot; (Master Builders), or approved equal.</li> Water: Clean, free of oils, acids, alkalis and organic matter.</li> </ol>

EQUIPMENT
<ol type="A"> Trowels</li> Chisels</li> Stiff bristle brushes (non-metallic) </li> </ol> =EXECUTION=

PREPARATION
<ol type="A"> Protection: Protect persons, motor vehicles, surrounding    surfaces of building whose masonry surfaces are     being restored, building site, and surrounding     buildings from injury resulting from masonry     restoration work.</li> Erect temporary protection covers over pedestrian    walkways and at points of entrance and exit for     persons and vehicles which must remain in operation     during course of masonry restoration work.</li> Contractor shall test those areaway drains, window    well drains, etc., which will be used to assure     that drains are functioning properly prior to     performing masonry restoration operations in those     areas. The Contractor shall report immediately to    the Construction Engineer the location of drains     which are found to be stopped up or blocked. </li> Prevent grout or mortar used in repointing and    repair work from staining face of surrounding     masonry and other surfaces. Remove immediately    grout and mortar in contact with exposed masonry     and other surfaces.</li> <li>Protect sills, ledges, windows, and projections    from patching material droppings.</li> </ol> </li> </ol>

ERECTION, INSTALLATION, APPLICATION
<ol type="A"> <li> Remove deteriorated concrete at spalls to sound material. Grind, chisel or saw cut =AB&quot; deep undercut around perimeter of patch. Clean with compressed air. Thoroughly remove any concrete showing traces of oils or grease.</li> <li>Thoroughly wet patched area prior to casting concrete patching material. If cement patching material manufacturer recommends a different procedure, such procedure is to be followed and executed in accordance with published instructions and in accordance with approved test patch.</li> <li>Install cement patching material in strict accordance with manufacturer's published instructions.</li> <li>Finish surface to match surface being patched, by grinding, troweling, sacking, or brushing.</li> </ol>

ADJUSTING/CLEANING
<ol type="A"> <li> After mortar has fully hardened, thoroughly clean exposed masonry surfaces of excess mortar and foreign matter using stiff nylon or bristle brushes and clean water, spray applied at low pressure.</li> <li> Use of metal scrapers or brushes will not be permitted.</li> <li> Use of acid or alkali cleaning agents will not be permitted.</li> </ol>