| Our Products |
|
| |
| Our services |
|
| |
| CONCRETE BLOCK |
|
20 full size units shall be measured for length, width and height. Cored units shall also be measured for minimum thickness of face, shells and webs. From these 3 blocks are to be tested for block density, 8 blocks for compressive strength, 3 blocks for water absorption and 3 blocks for drying shrinkage and moisture movement.
|
 |
|
| |
| Block Density |
| |
|
Three blocks shall be dried to constant mass in a suitable oven heated to approximately 1000C. After cooling the blocks to room temperature, the dimensions of each block shall be measured in centimeters to the nearest millimetre and the overall volume computed in cubic centimeters. The blocks shall then be weighted in kilograms to the nearest 10 gm. The density of each block calculated as follows:
Density in kg/m3 = Mass of block in kg/Mass of block in cm2 * 106 |
| |
|
|
 Water Absorption
| |
|
Three full size blocks shall be completely immersed in clean water at room temperature for 24 hours. The blocks shall then be removed from the water and allowed to drain for one minute by placing them on a 10 mm or coarser wire mesh, visible surface water being removed with a damp cloth, the saturated and surface dry blocks immediately weighed.
After weighing all blocks shall be dried in a ventilated oven at 100 to 1150C for not less than 24 hours and until two successive weighing at intervals of 2 hours show an increment of loss not greater than 0.2 percent of the last previously determined mass of the specimen.
The water absorption calculates as given below:
Absorption, percent =(A-B)/B * 100
Where,
A = wet mass of unit in kg.
B = dry mass of unit in kg.
|
| |
|
Compressive Strength
| |
|
The compression testing machine should be as per IS : 516-1959 and I.S : 14858-2000. 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 : 2185 (pert-I) – 1979 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.
TEST SPECIMENS
Eight full size units shall be tested within 72 hours after delivery to the laboratory, during which time they shall be stored continuously in normal room air.
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
|
| |
|
|
|
| |
 |
|
