Important Points SOP (Standard Operating Procedure) During the Inspection of RCC NP4 Pipes
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In this article,I am presenting few important most important questions with their answers, taken from various IS codes and books of civil engineering.These questions could be of your great help for your interview and general awareness about civil engineering. Please go through it.I hope it will expand your knowledge.
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(1.) Sand does not give strength to mortar but it helps in adjustment of strength of mortar due it helps in adjustment of strength of mortar due to change in its quantity. For example-1:1 mortar has more strength compared to 1:2, 1:3, 1:4 mortar.
(2.) 1 cum of wet mortar=1.25 cum of dry mortar.
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Presence of round aggregate decrease strength as for the given volume of aggregate.Because, development of friction in concrete is less due to its smoothness and lesser availability of surface area.
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(i) Better interlocking is provided
(ii) Surface area is more
(iii) More rough than round aggregate
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(6.) Elongation Index-Elongation index represent the % of particle, present in given sample having their longest dimension 9/5 or 1.8 times of its mean dimension.
(7.) Fineness Modulus-Fineness modulus is defined as sum of qumilitive percentage weight retained on the sieves of standard size/100.
(8.) Fineness modulus varies 2 to 3.5 for fine aggregate and 5.5 to 8 for coarse aggregate.
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(i) 150 micron
(ii) 300 micron
(iii) 600 micron
(iv) 1.18 mm
(v) 2.36 mm
(vi) 4.75 mm
(vii) 10 mm
(viii) 20 mm
(ix) 40 mm
(x) 80 mm
(10.) Fineness modulus of 'Z' represent third sieve 600 micron is average size of sample.Similarly, fineness modulus '5' represents average size of 2.36 mm.
(11.)
Sl.
No. |
Fineness
Modulus |
Range |
1 |
Fine Sand |
2.2 to 2.6 |
2 |
Medium Sand |
2.6 to 2.9 |
3 |
Coarse Sand |
2.9 to 3.2 |
(12.) In ordinary sand, bulking varies from 20 to 40% for increase in moisture content 5 to 8 %.
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(13.) Stages for concrete production are-
(i) Batching
(iii) Transportation
(iv) Placing
(v) Compaction
(vi) Finishing
(vii) Curing
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Also Read:Important terms/Points of civil engineering
(14.) For most important works, weight batching is used.
(15.) 1 Bag cement=Wt. 50 Kg.=Volume 35 Litres=Vol. 0.035 cum
(16.) Workability-Workability is defined as the property of concrete which determines the amount of useful internal works necessary to produce full compaction.
Or, in simple words, workability is how ease you can mix, transport, placed, 100% compact, finish the concrete.
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Slump Test (Image Source:Indiamart.com) |
(i) Slump Test
(ii) Compacting Factor Test
(iii) Vee-Bee Consistometer Test
(iv) Flow Table Test
(18.)
Sl.
No. |
Name
of Test |
Value |
1 |
Combined flakiness and elongation test |
Shall not exceed 40% for uncrushed or crushed aggregate |
2 |
Aggregate crushing value |
30 % maximum |
3 |
Aggregare Impact value |
|
|
(i) For wearing surfaces (such as runways, roads, pavements
etc.) |
30 % maximum |
|
(ii) For other than wearing surfaces |
45 % maximum |
4 |
Aggregate Abrasion Value |
|
|
(i) For wearing surfaces |
30 % maximum |
|
(ii)For non-wearing surfaces |
50 % maximum |
f'ck=fck+1.65s |
Sl. No. |
Nominal maximum size of aggregate |
Maximum water content |
1 |
10 mm |
208 kg |
2 |
20 mm |
186 kg |
3 |
40 mm |
165 kg |
Sl. No. |
Name of material |
Specific gravity |
1 |
Cement |
3.15 |
2 |
Water |
1 |
3 |
Coarse aggregate |
2.74 |
4 |
Fine aggregate |
2.74 |
5 |
Admixture |
1.145 |
6 |
Fly ash |
1 |
Sl. No. |
Age |
Strength Percentage |
1 |
1 days |
16% |
2 |
3 days |
40% |
3 |
7 days |
65% |
4 |
14 days |
90% |
5 |
28 days |
99% |
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Thermometer (Image Source:Globalhw.com) |
(33.) The store temperature of cement shall not exceed 400C.
(34.) The platform of cement bags will be more than 150 to 200 mm.
(35.) Concrete cover/Starter's grade will be always 1 grade higher than specified concrete. Sometimes also used Forsec conbertra GP2.
(36.) For hand mix concrete 10 % extra cement is used.(As per CPWD guidelines)
Also Read:Thermal power plant description
(37.) JMR-Joint Measurement Record
(38.) Variation of cube results=+-15 %
(39.) Plastisizer (5 to 10 %) and super plastisizer (upto 20 % reduce the water) is a water reducing admixture.
(40.) Both flaky and elongated particles may have adress effects on concrete and bituminous mix. They tend to lower the workability of concret and for bituminous mix, they particle may liable to breakup and disintegrate during traffic load.
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1+2+4=7
7 is the mixing proportion.
Volume of wet cement concrete=1.54 to 1.57
Unit weight of cement=1440 kg/cum
1 bag of cement=50 kg/bag
=50/1440 cum
=0.034722 cum
Cement=1.54/7
=0.22
=0.22/0.03472
=6.33 bags
1 bag cement=50 kgs.
=6.33 X 50
=316.82 Kgs.
Sand=0.22 X 2
=0.44 cum
Metal=0.22 X 4
=0.88 cum
(42.) Mortar is a mixture of matrix (Binding materials eg. cement, lime etc.) + Adultrants (Sand, Surkhi etc.)
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(a.) OPC (33, 43 and 53 grade)
(b.) Rapid hardening cement
(c.) Extra rapid hardening cement
(d.) Quick setting cement
(e.) Sulphate resisting cement
(f.) Super sulphate cement
(g.) Portland slag cement
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(i.) Low heat cement
(j.) Hydophobic cement
(k.) IRS T-40 cement
(l.) High alumina cement
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(a.) Loss of ignition test
(b.) Chemical composition test
(45.) Clinker is obtained as a result of fusion at a temperature of about 4000C to 15000C, generally 13000C temperature is kept in kiln.
As I read your Blog related with civil engineering it's really very informative ,with this I also explore some new information which I never know.
ReplyDeletehope in coming days You will share/serve more unknown information by your Blog.
Warm regards
Samir Kumar Das.