GAIL (India) Limited

446.3 RUBBLE MASONRY:-6.3.1. MATERIAL:-The stones to be used for the masonry shall be hard, sound, free from cracks, flaws etc., and shall be fromapproved quarries. They shall generally be freshly quarried with sharp edges and worn clean face. Theyshall be free from rounded, or weathered surfaces or skin or costing which prevents the adherence ofmortar. Size & shape of stone shall be as per the requirement.The stones to be used as headers, quoins, copings etc., shall comply with the requirements of facing andhearted as may be relevant and shall further comply with the facing stones shall be selected from the massof quarry stones for their greater size, goods beds, close grain and uniform colour. The beds and jointsshall have an average bearing of not less than 2 cm. The quoins shall be of selected stone and shallnormally be 10 cm. x 24 cm. x 39 cm. or as directed by Engineer-m-charge The faces of quoins shall berough tooled with 40 mm. chisel drafts at the corner edges. The beds and tops shall be dressed square tothe face and rough tooled to 10 cm from the face and vertical joints similarly dressed to 4 cm. from theface In the embedded portion the length of side shall not be less than that of exposed side apposite bymore than 8 cm for the longer side and 60 m for the shorter side.One through stone shall be provided per half sq m. of facing evenly distributed in a staggered pattern.They shall be about 0 03 sq m in face area and shall have a tailing of the full width of the masonry whenthe width of the masonry is 60 cm or less If the wall or masonry be over 60 cm. thick a line of headersoverlapping each other be atleast 15 cm. shall be laid right through wall a face to back The length of theinterior headers shall not be less than 45 cm & their average cross section area shall not be less than 0.025sqm. Face header shall be distinctly marked on its face.6.3.2 MORTAR:-Unless otherwise mentioned the mortar for masonry work shall be composed of 1 part of cement and 5parts of coarse approved sand The sand for mortar shall be as per I S, 2116-19656.3.3 SCAFFOLDING:-It shall be single or double as is warranted for the particular work Put log holes shall be made good bybricks to match the face work when put logs are removed after ensuring that the holes behind are solidlyfilled with 1:4:8 cement concretes.6.3.4 CONSTRUCTION:-The masonry shall be laid to lines, levels, curve and shape as shown on the drawings, fixtures, plugs,brames, pipes conducts etc., if any shall be built in at places when on the plans which laying the masonryand not later by removing the stones already laid.I. Stones in the hearting shall be laid on their broadest face which gives better opportunity to fill the spacebetween tones.II.Stratified stones must be laid on their natural beds. All bed joints shall be normal to the pressure uponthem.III.In battered walls, the beds of stone & the plane of course should be at right angles to the better.IV.If masonry is to be laid directly on excavated bed or concrete footing, the bed shall be cleared or all loosematerials, cleaned and wetted just before laying masonry. Bushings shall not project more than 40mm., infaces where joints are to be pointed or struck and 12 mm. in faces proposed to be plastered. Quoins in theunexposed portions shall have the same facing as the rubble stones and shall have uniform chisel drafts of40 mm. in the exposed portions and up to 15 cm. below the finished ground level, quoins shall be roughtolled with 40 mm. chisel drafts at the corner edges.V. The face stones shall be laid without any pinning on the exposed faces. In each course the headers or linesof headers as the case may be, shall kept in position as specified intervals and with specified laps wheresuch laps are required before the masonry of the layer is commenced to ensure that they are being laidproperly and in required numbers and intervals. They shall be embedded in mortar as masonry in that