Page 4 Advertisements Column 2

Evening Post, Volume CIV, Issue 7, 8 July 1922, Page 4

ARCHITECTS, BUILDERS, AND OTHERS. HUTT RIVER SHINGLE COMPANY. IS it good business to purchase and use inferior materials when, by a slight increase in cost, materials can be obtained that will give an increase in strength of at least 25 per cent. 1 You gain either by an increase in strength for the Bame weight, or obtain the requirod strength of structure by the uso of less material. ' In the latter case the cost would be approximately the same as when the inferior materials are used, owing to four causes — a. Less material to purchase. b. Less material to cart. c. Loss material to work into place; and d. The size of the foundation and other parts will be reduced owing to there .being less weight to carry. But a structure of more certain strength is obtained. The above-mentioned points must all be considered in building construction, and the increase in strength for the same weight is by no means of small importance when the life of the.building is taken into account, especially in an earthquake country. ; Havo you ever' considered the effect of silt in your concrete materials ? Experience and experiments have shown that silt, mud, or similar substances havo a deleterious effect upon the setting, as well as upon the strength, of the concrete, with a resulting decrease in its strength. It is not known exactly why this is so, but when you consider the enormous proportion of surface area to volume of the fine particles of the silt, and that the whole of this surface has to be covered '. with the cement, the fact impresses itself on one of how impossible it is for a limited quantity of cement to do this, eSDecially as particles of cement before setting are approximately the same size as the particles of 'silt. To _ obtain the best results, first-class practice in concrete construction calls for sand composed of sharp, hard, and gritty grains, and not more than 10 per cent, should pass" a sieve having 2500 mashe'a per square inch—that is, particles l-64th of an inch and smaller in size. . Just recently tests havo been made at the Canterbury University, and also by a well-known corporate body in Wellington, and the average results of these tests give a. breaking strength for unwashed Hutt River Shincrle of 22401b per square inch. For Hutt River Shingle Company's Stone, crushed, 'washed, and, graded, and washed sand, a breaking strength of 29001b por square inch. This shows an increase in strength of over 25 per cont. in favour of 'crushed' stone and clean material. ' This increase in, strength is due to two causes—the use of clean material and the use of crushed stone. -On water-worn stone the surfaco has been worn smooth', and the bond between the cement and the stone is by adhesion - only. ..'■'..■ The surface of a fracture varies with each class of. rock, but generally it is rough, with little indentations. The cement in this case has a greater surface to adhere to, owing to the roughness, and 14 ™, obti"ns a bond in the indentations. Therefore, concrete made , with broken stone must be stronger than when smooth stones are used. '-.:.-,! No one can afford to risk endangering tho safety of' any building by tho use of inferior materials, as the strength of ._, column or beam depends upon the strength of tho woakest batch of concrete used. : ■ Nobody can foretell the strength' of concrete made with dirty materials, nor when the materials are not mixed in their proper proportions—that is to say. the dimensions of the particles of sand and stone must bear a proper relative proportion to the mass. It is impossible to obtain this result by the.haphazard methods generally in use at the present, time. The best results can only be obtained by separating the stones and sand by screening, and then measuring them in their proper proportions in small batches at the time of mixing the concrete. . / All high-class specifications the world over now call, for absolutely':.clean and properly graded concrete materials, so as to j ensure, as near as is humanly possible, that'the resulting concrete shall bo even iiv quality and; strength- throughout' the structure ■■ Can. you afford to depart. from what practice has shown to.be absolutely necessary through, repeated failures? By the foregoing we" have endeavoured to point out the advantages of the use of the best and cleanest materials in concrete construction; and we will have much pleasure in referring interested parties to the results of further tests that are available. COAL! WE have ]mt received a shipment of Scrcenod BURKES CREEK COAL, Classed .as tho BEST , HOUSEHOLD COAL in the Dominion. Burns with a. long flame, gives a olear, clean fire, with practically NO ASH. Orders taken City or Suburbs, in any, quantity. J. BAINBRIDGE AND SON, Tel. 22-951. . ' . ,- 27, Chuziiee.-st. MILNER'S STORE, KILBIRNIE. Tol. 24-429. WAIPA COAL WILL give you a cheerful fire, with plenty of heal, ft is most satisfactory in tho kitchen range. Burns clean, and the fire does not go out. The Price has boen Reduced. SAMUEL BROWN, LTD,, Tory-street, ■ " ' Office ' Willis-street, Tol. 21-240. Tel. 88. Tel. 124. pOAL! COAL! COAL! V REDUCED PRICES! Westport Household Coal—Town price, 3s od por cwt. Suburbs, 3s 9d per cwt. J. MURRAY AND CO. (Established over 30 years) Coal, Wood, and Produco Merchants, 137-189, Adolaido-road, Wellington. ' Telephone 24-156. J" 0 N E S AND CO., Clyde-quay, Wellington, Manufacturers of Clyde Brand Antifriotion Metals, Solders, etc, Specialists in Printers' Metals—Mono., , . Lino., and Stereo. . Full Stocks of Copper Sheets and Tubes. Brass Sheets and Tubes, Tin, Antimony, Lead, Engineer Sundries. SACKS! , .". SACKS! '. WANTED to Buy, Second-hand Sacks of every description; high^t prices given; also, Old Rope, Sacking, and Rags. A, V. STEWARD, LTD., Knigge-aveuue, Tel. 20-119. Off 'Vivian-street. XXT ANTED T O B U V, Scrap Copper, Brass, Lead, Zinc, Rope, Sacks, and Sacking. STEVENS AND CO., 132b, Abel. Smith-street.-. Telephone 20-355. T^T A N -FED KNOW N. All kinds of Cemetery Work executed. . Granite and Marble Curbs, Reinforced Concrete Walls. Direct Importer Granite and Marble Memorials. 11. GLOVER, i Monumental Sculptor. 59, Kent-terrace. Telephone' 21-783. ALMONDS, Is . lb; New Season's Packet Dates, lid packet; FourCrown Dessert Figs, Is lb: Mixed Chocolates, Is lid lb; Pearl's British Chocolates 3s lb are superb. A reduction of Id por lb to anybody mentioning, this advl. „ URH, : I,lSMflUKilli, ■90, Williß-BtTcH': & Uqoro above Eyauing. Post),