Which code follows for measurements as per cpwd specifications.?
IS 1200 for measurements.
How will trucks be checked on-site when receiving concrete?
A. Revolution Counter
B. Ticket Checked for Concrete Batching time and Slump Value at the plant.
C. Slump Test.
D. Temperature Test (32 C maximum @ Site).
E. Assure Lab Technician is present at the site and performs testing.
F. 6 Cubes or 4 Cylinders should be taken per 50cum or recommended in the project specification.
When will you apply the curing of the concrete?
After the concrete has initially set (35 to 40 minutes is the initial setting time of concrete)
Max and min slope of chutes used in pouring concrete?
Max slope is 1:2 (Vertical to Horizontal), Min slope is 1:3
–What is the mixing time of a stationary or central batching plant (concrete)?
50 to 90 seconds
What is the agitating speed of the mixer?
2 to 6 revolutions per minute (rpm)
What is the mixing speed of the mixer?
6 to 18 rpm
What is concrete fatigue?
It is the weakening of a material caused by repeated loads.
What is creep?
It is deformation due to the sustained load.
How would you know if the concrete has gained its initial set?
If there is no more water seen (brightness) on the surface of the concrete, or if there is no water on the surface of the concrete.
If agitated concrete is discharged after more than one hour, what will happen?
The concrete is over mixed, becomes hot, and the strength is reduced
What is the difference between recovery schedule and revised schedule?
Recovery schedule keeps the same finish date with some corrective actions to recover the delay such as add more resources and break down some activities and
so on… Revised schedule we have a new finish date because of claims or adding a new scope of work (amendment }
Who invented Portland cement and in which year?
Joseph Aspdin patented Portland cement in 1824. William Aspdin, his son is regarded as the inventor of modern Portland cement due to his developments in 1840s.
Which equipment is used to test the setting time of cement?
Core cutter is used to determine dry density of soil. Vibrator is used in sieve analysis. UTM can be used to test various parameters – tension, bending, shear of various materials. Vicat apparatus consists of a needle, used to penetrate the cement paste sample.
What is the depth the needle in Vicat apparatus should penetrate into the cement paste in consistency test?
The best procedure has been clearly mentioned in IS 4031 Part 4. According to the code, 33-35mm depth of penetration is ideal.
In an R.C.C structure, the tension zone lies ?
In the R.C.C. structure, there is a neutral axis in the middle, where no compression and tension is there. Layers above it are subjected to compression and the ones below it is subjected to tension.
Which of the below structure doesn’t require PSC?
Arches don’t require PSC. They are not under so much compression and loading. All other structures carry heavy loads and hence will be efficient if PSC is used.
In which beam tension capacity of steel is greater than combined compression capacity of steel and concrete?
Over-reinforced beams have higher tension capacity. So, these beams fail by crushing of compression zone concrete, without any warning.