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<br />Version 10/31/2017 Page - 14 Public Works Quote <br />B. Preparation: Perform the following in addition to requirements of PREPARATION of this Section: <br />1. Remove by handchipping all loose, damaged concrete to sound material. <br />2. Where existing reinforcing is exposed, remove concrete to minimum of one-inch around exposed <br />bars. If existing bars are cut through, cracked, or cross-sectional area is reduced by more than 10 <br />percent from original, immediately notify Engineer. <br />3. Score-cut perimeter of area to be repaired to minimum depth of 1/2-inch and maximum depth that <br />will not cut existing reinforcing steel. Chip out existing concrete to the score line so that minimum <br />thickness of repair mortar will be 1/2-inch. <br /> <br />C. Repair Material: <br />1. Completely fill the surface defect with specified repair material, in accordance with material <br />manufacturer’s instructions and the Contract Documents. <br />2. Perform, with repair mortar, repairs of surface defects in concrete normally in contact with water or <br />soil, and interior surfaces of structures that contain water. <br />3. Repair of other surface defects may be by applying repair mortar, repair concrete, shotcrete, or <br />cement grout, as appropriate. <br />Repair of Deteriorated Concrete: <br />A. This Article pertains to deteriorated concrete which has been damaged due to corrosion of reinforcing <br />steel, physical damage due to abrasion, or damage due to chemical attack. Use repair mortar, as <br />specified in this Article, for repairing deteriorated concrete. <br /> <br />B. Surface Preparation: In addition to requirements of the PREPARATION section, perform the following <br />surface preparation: <br />1. Remove loose, broken, softened, and acid-contaminated concrete by abrasive blasting and <br />handchipping to sound, uncontaminated concrete. <br />2. Upon completion of removal of deteriorated concrete, notify ENGINEER in writing. Allow one week <br />for ENGINEER to evaluate the surface, perform testing for acid contamination if required, determine <br />if additional concrete shall be removed, and to develop special repair details (if any) required. <br />Should ENGINEER determine that additional concrete be removed to reach sound, <br />uncontaminated concrete, allow another one-week period for further evaluation and testing <br />following the additional removal. <br />3. Surface preparation shall conform to recommendations of repair mortar manufacturer. <br />4. Repair and rehabilitate isolated areas of exposed reinforcing bars in accordance the REPAIR OF <br />SURFACE DEFECTS section. If extensive areas of reinforcing steel are uncovered after removal <br />of deteriorated concrete, ENGINEER will determine the repair methods required. <br /> <br />C. Repair Mortar Placing: <br />1. Conform to manufacturer’s recommended procedures for mixing and placing repair mortar. <br />2. After initial mixing of repair mortar, addition of water is not allowed. <br />3. Minimum Thickness: <br />a. Install repair mortar to not less than minimum thickness recommended by manufacturer, and <br />not less than 1/2-inch. <br />b. Where removal of deteriorated concrete results in repair thickness of less than minimum <br />required thickness to return to original concrete surface in isolated areas totaling less than 10 <br />(ten) percent of total repair surface area, remove additional concrete to obtain at least the <br />required minimum thickness. <br />c. Where surface area with repair thickness less than minimum required thickness exceeds 10 <br />(ten) percent of total repair area, notify ENGINEER. <br />d. Provide repair mortar so that minimum cover over existing reinforcing steel is two inches. Do <br />not place repair mortar creating locally raised areas. <br />e. Where transitioning to or from wall surfaces not requiring repair, do not feather-out repair mortar <br />at transition. Instead, form the transition by saw cutting a score line to not less than minimum <br />required repair mortar depth and chip out concrete to the saw cut line. Do not cut or otherwise <br />damage reinforcing steel. <br />4. Place repair mortar to an even, uniform plane to restore concrete member to its original surface. <br />Out-of-plane tolerance shall be such that the gap between 12-inch long straight edge and repair <br />mortar surface does not exceed 1/8-inch, and gap between a four-foot long straight edge and repair