لخّصلي

Preparation of Cubes ?Operate the compression testing machine using the supplied operational manual.Immediately after mixing, fill the molds heaping full without compacting while resting on an un oiled metal base plate.Use a graduated cylinder to measure out the mixing water so that the water-cement ratio is 0.40, 0.45, and 0.50.Apply this pressure 12 times to each cube over the entire surface, then heap the mortar above the mold and smooth it off with a trowel.Weigh out the cement and the sand separately so that the total weight is 2250 gm ?Then press the mortar in firmly, using both 11

thumbs simultaneously.Curing of the Specimens All specimens will be moist cured for one day and after moist curing the specimens will be water cured in water curing tub.Add the remainder of the sand and mix vigorously for 2 min.Repeat the operation of heaping, thumbing and smoothing off.Measure the critical cross-sectional dimensions to the nearest 0.01 in. ?(600 gm cement, 1650 gm sand).Following steps are to be followed for mixing the ingredients: ????????????

Preparation of Cubes
 Weigh out the cement and the sand separately so that the total weight is 2250 gm
 (600 gm cement, 1650 gm sand). Use a graduated cylinder to measure out the
mixing water so that the water-cement ratio is 0.40, 0.45, and 0.50.
 Following steps are to be followed for mixing the ingredients:
 Place the water in a dry bowl
 Add cement to the water and mix for 30 sec.
 Add approximately one-half of the sand and mix for 30 sec.
 Add the remainder of the sand and mix vigorously for 2 min.
 Immediately after mixing, fill the molds heaping full without compacting while resting on an un oiled metal base plate. Then press the mortar in firmly, using both
11

thumbs simultaneously. Apply this pressure 12 times to each cube over the entire surface, then heap the mortar above the mold and smooth it off with a trowel. Cover the mold with an oiled base plate, turn the mold upside down and remove the un oiled base plate. Repeat the operation of heaping, thumbing and smoothing off.
Curing of the Specimens
All specimens will be moist cured for one day and after moist curing the specimens will be water cured in water curing tub. Testing will be done after 3, 7 and 28 days.
Testing Cubes
 Remove the specimens from the water bath and test as soon as possible, keeping all specimens covered with a damp cloth until tested.
 Measure the critical cross-sectional dimensions to the nearest 0.01 in.
 The cubes should be placed in the testing machine after the removal of loose
particles from the surface.
 Operate the compression testing machine using the supplied operational manual.
 Apply the load so that the maximum load will be read within 20 to 30 seconds.
Record the maximum load indicated by the testing machine.
 Remove the broken cube from the testing machine and observe the apparent angle
between the failure surface and the base of the cube.
 Test all the cubes to be tested on specified day.
 Remaining cubes will be tested in similar manner after 7 and 14 days.
 Record the readings in the given table below.