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.. -retentivity, freed~m from cracks and go~d resistape agahstram penetrqtion. Commonly adopted mixes are' 1 : 1 : 6,1:2 :9add 1 : 3 : 12BDetails of mortars for rnasonr are contained in IS 2250 of 1965 'Codeof Practice for preparation and use a masonry Mortars' and< IS 1625 of 1971'Code of Practice for preparation and use of lime mortars'. Strength of variousmortars are given .,.* T+ble 1 bclow :, ~ a ~ c I I .i&o~~a~ss~ve;(Cement, , . . , :-, I Lime Sur2 ,-r - .it.I.'~ -,1-STREN&~,(D$ . , -I MASONRY MORTARSMix4.g;' :i , , ,2u ana above0 3'nR 50 and above .-- i4"'2. 1 (. .I,, a ' - a .d!f+!3.3 Mortar strength shall i general be not &ter than that of masonry and. , I I . , f , I4.1 As a general rule, apart from strength of masonry units#d grade ofmmar, strength of masonry depends on the uniformity of sip .qnd shape ofunits. Units which are true in shape and size can be laid with 'ctsmparativelythinner joints, thereby resulting in hi&r stren h. For this reason, use of'A'grade.bricks givw masouy of higher stmn !?as compred to that with Bgrade, .bricks wen. though crushing strength of grade bricks may be same asthose af A g~ade. For simjlar reasons. ashlar st oqe masonry which uses muratelydressed and shaped stme blocks is much stpager (nearly double) 'th&coursed stone msnory. Znm-m in thickness of bed joints from 1 Ornm to 16mmd masguy b s pr@xirnat$y 25%. For kick masomy ywrkprovisionsmnpo IS 2212 of 1962 ' 8 o f e of Pxactlce for brick work' are to be folIow-ed. . Details of bond, bedding and jointing are laid down in thjs code. Poorworkmanshi may seriously impair .the strength of brick work and 'introdw,weakness w g ish rnw permi$ ,moisture pnetratjoa and other defects. Themain defects in w6rkmanship which impair the gtrenah of mlyqng arc asunder :- ' ,A?,- , /. , -toi4 -, . - .- + h -. -.:$a1 ~';,.>,*iifd;'(a) Use of dry bricu~ot properly s o w in wate.. ..JT~ .,Q c , ~ .
(c) Failure.tobed joints(d) Deviation from verticaI Plane or alignment i.2. out of plumb masonry.(e) Unfavourable curing conditions.Tolerances permissible in the masonry are given in table 2 below :TABLE 2 MAXIMUM PERMISSIBLE TOLERANCES IN MASONRYSI No. Item Tolerance(1) Deviation from the position shown onplan of any brickwork more than onestorey in height(2) Deviation from vertical within a storey 6mm per 3m height(3) Deviarion from vertical in the total height of .12.5mmbuilding.(4) Relative di spIacement between load bearing 6mmwalls in adjacent storeys intended tobe in vertical alignm,nt(3 Deviation from line in Plan6mm12.5.mm total12.5 mm total
Page 1 and 2: RESTRICTEDTECHNICAL INSTRUCTIONSNEW
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Page 9 and 10: F III 'I9.3 h&mYllall.9.3.1 The thi
Page 11 and 12: Note-1wnear interpolation betwcen v
Page 13: Note92 Pot uunaidod mawpry, the .la

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