Remove unevenness observed the bed faces of bricks to provide two smooth parallel faces by grinding. Immerse the bricks in water at room temperature for 24 hours, then remove the specimen and drain out any surplus moisture at room temperature.
Fill the frog and all voids in the bed faces flush with cement mortar 1 cement, 1 clean coarse sand of grade 3mm and down. Store it under the damp jute bags for 24 hours filled by immersion in clean water for 3 days.
Remove and wipe out any traces of moisture. The common burnt clay shall be classified on the basis of average compressive strength as given in table. Join Join TheConstructor to ask questions, answer questions, write articles, and connect with other people. Tuesday , 23rd November Centage Tariff Funding Sources. At Madurai Lab only The materials received from local bodies and private agencies are also tested for quality in these laboratories.
Phone No : Emaiil : aeeqcltwadcbe gmail. Phone No - Emaiil : aeeqtlmdu gmail. The average of three specimens gives the crushing strength of concrete. The strength requirements of concrete. The strength of concrete increases with age. The table shows the strength of concrete at different ages in comparison with the strength at 28 days after casting.
A concrete cube test or concrete cylinder test is generally carried out to assess the strength of concrete after 7 days, 14 days or 28 days of casting. The compression testing machine is used for testing the compressive strength of concrete. Join Join TheConstructor to ask questions, answer questions, write articles, and connect with other people. Have an account? Log in Now. Join for free or log in to continue reading Remember Me!
S : The load capacity, platens sizes, vertical space between platens and horizontal space between machine columns shall be as per the requirements of the specimens to be tested. However, IS : pert-I — specified that when the bearing area of the steel blocks is not sufficient to cover the bearings area of the blocks, steel bearing plates shall be placed between the bearing blocks and the capped specimen after the centroid of the masonry bearing surface has been aligned with the centre of thrust of the bearing blocks.
It is desirable that the bearing faces of blocks and plates used for compression testing of concrete masonry have hardness of not less than 60 HRC. When steel plates are employed between the steel bearing blocks and the masonry specimen, the plates shall have thickness equal to at least one-third of the distance from the edge of the bearing block to the most distant corner of the specimen. In no case shall the plate thickness be less than 12 mm. Advertisements ASTM : C specified that when the bearing area of the upper platen or lower platen is not sufficient to cover the area of the specimen, a single steel bearing plate with a thickness equal to at least the distance from the edge of the platen to the most distant corner of the specimen shall be placed between the platen and the capped specimen.
The length and width of the steel plate shall be at least 6. Thickness of bearing plates has a significant effect on the tested compressive strength of masonry units when the bearing area of the platen is not sufficient to cover the area of the specimen. Tested compressive strength will typically increase with increased plate thickness and with reduce distance to the further corner of the specimen.
Accordingly the CTM platens shall have the required dimensions with respect to the specimens to be tested on it. For the purpose of acceptance, age of testing the specimens shall be 28 days. The age shall be reckoned from the time of the addition of water to the dry ingredients.
The gypsem and water paste shall be spread evenly on a non-absorbent surface that has been lightly coated with oil. These shall be within the specified limits for different classes of bricks. In this article, we give only an outline of most important points of these tests.
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