1927 (#803-839) - Laserfiche WebLink

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9xcess of the maximum dimension specified aa follows: Not more than five (8) per cent by weight, of flat, think, or elongated pieces or particles of stone, will be permitted in any class or size of broken stone or gravel. Pieces or particles of stone wh~e greatest thickness does not equal or exceed twenty (20) per cent of its greatest length will be considered as flat, thin or elongated. The gravel, broken stc~e or both shall conslst of sizes ranging from a minimum of not more than five (8) per cent by weight, passing a scr~en having one- fourth (~) inch round epenings to a maxim~mm size that shall pass a screen having two (2) inch round openings, and shall contain sizes of which not more than ninety-five (95) per cent by weight, will pass a screen having one and one-half (1b) inch round openings and not less than twenty-five (25) per cent or more than sixty ($) per cent, Dy weight, will pass a screen having three-fourths (3-4) inch round openings.' The water used in mixing all concrete and mortar shall be reasonably free from alkali, silt or other impurities, and in no case shall the amount of solids exceed three .(3) grams per lltre. V~ere alkali predominates in the solid matter, the solids shall not exceed one and one-half (lb) grams per litre. Section 5. Joints and Fillers. Expansion Joints shall be constructed at locations hereinafter specified or when shown or other~ise indicated on the plans. bitumen, shall be ness and The filler for the expansion joints shall consist of prepared strips of or fibre matrix and bitumen, or similar material of a~proved quality, and one-half (~) inch in thickness and the width shall be equal to the thick- the width shall De equal to the thickness of the pavement. The Joint filler shall be placed in a vertical position and at right angles to the center line of the walk. On cm~pletion of the ~idewalk the lower edge of the filler shall be in contact with the subgrade for its entire length. The joint filler shall be supported by a well staked steel or wooden bulkhead or header of sufficient strength to hold the same in a vertical position as well as in a straight line until the contract has been placed and tamped, after which the bulkhead or header shall be removed and the space carefully filled with additional concrete and thoroughly tamped. The contracto~ shall use extreme care in the placing of expansion joint fillers to prevent damaging them during the placing, tamping, and finishing of the concrete. Before the walk is opened to traffic, all expansion Joint fillers shall be trimmed flush with the surface of the walk. Part III Concrete and Mortar Section 1. Concrete Proportions. All concrete shall be mixed in the proportions of one (1) bag of Portlan. cement to not more than two (2) cubic feet of concrete sand, to not mor'e than fottr (4) cubic feet of either crushed stone or gravel or both, and in no case shall~the volume of~ the fine aggregate be less than one-half (~) the volume of the coats aggregate. .- The voids in the concrete shall be completely f~lled with ~mortar. If voids appear this condition shall ~e remedied bM reducing the. prop~x'tion el, coarse aggregate and not by increasing the amount of fine aggregate. The amount ~f mixing water used sha.ll be the least quantity that will produce a workable mixA · A cubic yard of concrete in p~ace shall contain, not less than six (6) bags of Portland Cement. Sectio~ 2, Mixing Concrete. The concrete shall be mixed either by machine or oy hand as herein- after Specified: (a) MACHISE ~IX~G. If a machine mixer is used, the Contractor shall mix without spilling,, such quantity of aggregates as will b e within the capacity of the mixer, and in no case shall the quantity be such as to require the splitti~ of a sack of cement. The mixer drum shall have a speed of not less than thirteen (13) revolutions, nor more than twenty (20) revolutions per minute and every batch of concrete shall be mixed in the drum of the mixer not less £ha~ sixty (60) seconds before any portion of the batch is discharged. The drum shall not be charge~ while the mixer is discharging. (b) HAND MIXING. ~ere concrete is mixed by hand, one (!) box of rock shall be placed on a tight platfonn, not less than ten (10) feet wide and twelve (12) feet long. Upon the rock shsll be placed one (1) box of sand and upon this shall be placed the requisite number of sacks of cement. The inspector shall be given the opportunity to check the nxuuber of sacks of cement on each batch before the sacks are opened.