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The patching mixture shall be made of the same materials and of approximately the same <br /> proportions as used for the concrete,except that the coarse aggregate shall be omitted and the <br /> mortar shall consist of not more than 1 part cement and 2-1/2 parts sand by dam loose volume. <br /> White Portland Cement shall be substituted for a part of the gray Portland Cement on exposed <br /> concrete in order to produce a color matching the color of the surrounding concrete,as determined <br /> by a trial patch. The quantity of mixing water shall be no more than necessary for handling and <br /> placing. The patching mortar shall be mixed in advance and allowed to stand with frequent <br /> manipulation with a trowel,without addition of water,until it has reached the stiffest consistency <br /> that will permit placing. <br /> After surface water has evaporated from the area to be patched,the bond coat shall be well <br /> brushed into the surface. When the bond coat begins to lose the water sheen,the premixed <br /> patching mortar shall be applied. The mortar shall be thoroughly consolidated into place and <br /> struck off so as to leave the patch slightly higher than the surrounding surface. To permit initial <br /> shrinkage,it shall be left undisturbed for at least 1 hour before being finally finished. The patched <br /> area shall be kept damp for 7 days. Metal tools shall not be used in finishing a patch in a formed <br /> wall which will be exposed. <br /> B. Tie Holes <br /> After being cleaned and thoroughly dampened,the tie holes shall be filled solid with patching <br /> mortar. <br /> C. Proprietary Materials <br /> If permitted or required,proprietary compounds for adhesion or as patching ingredients may be <br /> used in lieu of or in addition to the foregoing patching procedures. Such compounds shall be used <br /> in accordance with the manufacturer's recommendations. <br /> 3.06 FINISHING OF FORMED SURFACES <br /> Immediately after removing the forms,the form ties shall be cut back 3/4"from the surface and patched <br /> with 1:2 cement-sand mortar. All honeycombs,voids,and other defects shall be so patched. The surfaces <br /> shall then be thoroughly wetted and rubbed with a No. 16 Carborundum stone or equal abrasive brining the <br /> surface to a paste. The rubbing shall be continued sufficiently to remove all form marks and projections, <br /> producing a smooth,dense surface without pits or irregularities. After setting sufficiently,the surface shall <br /> then be rubbed with a No.30 Carborundum stone until the entire surface is of a smooth texture and uniform <br /> in color. Only exposed surfaces in habitable areas need be rubbed. Surfaces to be waterproofed or hidden <br /> from view shall be patched,but not rubbed. <br /> 3.07 PATCHING <br /> The total patched area shall not exceed two square feet in each 1,000 square feet of surface. This is in <br /> addition to form tie patches. <br /> Any patches shall closely match the color and texture of surrounding surfaces. The mix formula for <br /> patching mortar shall be determined by trial to obtain a good color match with the concrete when both <br /> patch and concrete are cured and dry. After initial set,surfaces and patches shall be dressed manually to <br /> obtain the same texture as surrounding surfaces. <br /> END OF SECTION <br /> Section 03310-Page 8 of 8 9/17 <br />