Removed from surfaces for which finishes f2 and f3

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Unformatted text preview: the prescribed lines, shall be removed and replaced with dry-1)atching mortar. Where bulges and abrupt irregularities protrude outside the reqnirecl limits and where it is required to finish the surfaces with iinishes F2 and F3, the protrusions shall be reduced by bush-hammering and grinding so that the surfaces are brought within the required limits. Drypack filling shalt he used for holes having at le,ast one surface dimension not greater than the hole depth, for holes left by removal of fasteners from the ends of ,form tie rods, for grout pipe recesses, and for narrow slots cut for repair of cracks. Filling of holes left by the removal of fasteners from the ends of the tie rods in surfaces for which Fl finish is specified, shall not be required. Dry-patching mortar shall consist of one part of cement to two parts of sand by volume, and just enough water to hold the ingredients together. The mortar shall be placed in layers of 2.5 cm (or 1 in ) each layer thoroughly tamped, an? the finishing layer shall bc smoothened to form the surface continuous with 26 IS : 457 - 1957 .the surface of the holes and shall be sound and free from shrinkage and surrounding concrete. All tilling shall be bonded rightly hollow areas after the fillings have been cured and have dried. 4.16 cracks to the Finiehea and [email protected] 4.16.1 Concrete surfaces shall be tested where necessary to deter mine whether surface irregularities are within the specified limits. Surface irregularities are classified as ‘ abrupt ’ oi *gradual ‘. Offsets caused by displaced or misplaced form sheathing or lining or form sections, .or by loose knots in forms or otherwise defective timber forms shall be considered as abrupt irregularities, and shall be tested by direct measurement. All other irregularities shall be considered as gradual irregularities, and tested by use of a template, con&sting of a straight edge or the equivalent thereof for curved surfaces. The length of the template shall be 150 cm ( or 5 ft ) for testing of formed surfaces and 300 cm ( or 10 ft ) for testing of unformed surfaces. 4.16.2 Formed Surfaces - The finish shall be of the following four classes: 4 ‘4 cl for formed concrete surfaces Finish Fl - Finish Fl shall apply to formed surfaces upon which or against which backfill or concrete is to be placed. The surfaces require no treatment after removal of forms except removal and repair of defective concrete and the specified curing. Correction of surface irregularities shall be done only for depressions which when measured as described under 4.16.1 exceed 2.5 cm ( or 1 in ). Finish F2 - Finish F2 shall apply to all permanently exposed formed surfaces for which finishes F3 and F4 arc not specified. Surfaces for which finish F2 is specified will need no filling of pits or sack rubbing and no grinding other than that needed for repair of surface imperfections. Surface irregularities, measured as described under 4.16.1 shall not exceed 0.5 cm ( or t in ) for abrupt irr...
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