1. REQUIREMENTS
a) Specified minimum strength = 20 N/Sq mm
b) Durability requirements
i) Exposure Moderate
ii) Minimum Cement Content = 300 Kgs/cum
c) Cement
(Refer Table No. 5 of IS:456-2000)
i) Make Chetak (Birla)
ii) Type OPC
iii) Grade 43
d) Workability
i) compacting factor = 0.7
e) Degree of quality control Good
2. TEST DATA FOR MATERIALS SUPPLIED
a) CEMENT
i) Specific gravity = 3.05
ii) Avg. comp. strength 7 days = 46.5 more than 33.0 OK
28 days = 55.0 more than 43.0 OK
b) COARSE AGGREGATE
i) 20mm Graded
Type Crushed stone aggregate
Specific gravity = 2.68
Water absorption = 1.46
Free (surface) moisture = 0
c) FINE AGGREGATE (Coarse sand)
i) Type Natural (Ghaggar)
Specific gravity = 2.6
Water absorption = 0.5
Free (surface) moisture = 1.4
3. TARGET MEAN STRENGTH (TMS)
a) Statistical constant K = 1.65
b) Standard deviation S = 4.6
Thus, TMS = 27.59 N/Sqmm
4. SELECTION OF W/C RATIO
a) As required for TMS = 0.5
b) As required for ‘Moderate’ Exposure = 0.55
Assume W/c ratio of 0.5
5. DETERMINATION OF WATER & SAND CONTENT
For W/C = 0.6
C.F. = 0.8
Max. Agg. Size of 20 mm
a) Water content = 186 Kg/cum
b) Sand as percentage of total aggregate by absolute volume = 35 %
Thus,
Net water content = 180.42 Kg/cum
Net sand percentage = 33 %
6. DETERMINATION OF CEMENT CONTENT
W/c ratio = 0.5
Water content = 180.42 Kg/cum
Thus, Cement content = 360.84 Kg/cum Adequate for moderate exposure Say 360 Kg/cum
7. DETERMINATION OF COARSE AND FINE AGGREGATE CONTENT
Assume entrapped air as 2 %
Thus,
0.98 cum = [180.42+360/3.05 + {1/0.33}*{fa/2.6}]/1000
& 0.98 cum = [180.42+360/3.05 + {1/0.67}*{Ca/2.68}]/1000
Hence,
fa = 584 Kg/cum
Ca = 1223.8 Kg/cum
The final mix proportions of M-20 grade of concrete become:-
Note: 1 The above recommended mix design must be verified, by actual cube tests.
2 The mix design is based on the quality and grading of the materials actually supplied, by the client.
Any variation in quality and gradation will result in changes in the mix design.
This mix design was submitted by a regular contributor to this site. We are thankful to him for his excellent service.
If you have a query, you can ask a question here.
hello,
will u plz tell me what is the ratio of M30, M35 AND M40 grade concreat
thanku for this information
would u plz tell me that how much water should be mixed in -15
approx 146 litres , but can vary according to site conditions and temp. variation
27 liter
Hi, I am very keen to know and understand the ratio proportion of sand cement in unit of one [tagara] or [ghamela] of five kg capacity and the quantity of water required in making M-20 mortar
Dear M20 is not mortar it is a grade of concrete.
ratio of M20 nominal mix is 1:1.5:3
if one tagara is 5kg than your proportion is
cement 1 tagara = 1×5=5kg
sand 1.5 tagara= 1.5×5=7.5 kg
c.aggregate 3 tagara= 3×5=15 kg
What is the harm, if the M20 grade cube test result comes 46N/sqmm?
nothing technically but it effects economically . You can deduct the cement content u r using to reduce your cost
Sir,
I want to know how to take requirement for m15,20,25,30,35 concrete.
And i am eagerly waiting for your replay
Thanks and regards
Sowkath ali
Your question is not very clear to me however to know the quantity you of concrete require to work done calculate the quantity from drawings (may be you studied in Estimation and costing book , how to calculate the quantity )
kindly show me the different requirement on the classes of cement
Dear Sir,
I am a Civil Engineer.could you send me the detailed calculation report for how to calculate the quantities of cement sand & metal for each mix proportion(1:4:8,M10,15,20,25,30
Dear sir,
If the cement weight of cement is 1440 Kg/cum than how the Sp.Gravity is 3.15 kindly suggest
thank u sir i got that wat i needed….
Bt plz send me more details of m20.
M 20 – is a grade of concrete.
Nominal mix of M20 grade is 1:1.5:3 (1 cement: 1.5 C.Sand :3 C.aggregate)
Compressive strength of M20 grade is 20 N/sq mm in 28 days
I am a Civil Engineer.could you send me the detailed calculation report for how to calculate the quantities of cement sand & metal for each mix proportion(1:4:8,M10,15,20,25,30
To calculate the quantities of material of concrete you can follow this procedure.
Quantity of cement in one cum
= 1.54/sum of ratio of concrete to be used
1.54 is the density of wet concrete of one cum
For example you have to calculate material of 1:2:4 for one cum
cement = 1.54/1+2+4 = 0.22 cum
qty of cement per bag = 0.034cum
no. of bags in one cum = 0.22/0.034 =6.47
0ne bag have 50 kg of cement so 6.47X50= 323.5 kg/cum
Sand =0.22 X 2 = 0.44 cum X 35.28 = 15.52 cuft
c. aggregat = 0.22 x 4 = 0.88 x 35.28 = 30 cu ft
1.52 is actual density of materials…
dear these are mix designs of concrete used where high compressive strength is required . There is no such fixed ratio for concrete above M25 grade. you have to design the ratio according to the quality of material you are using
kindly tell me the IS codes used in mobile tower foundation
kindly tell me the proper mixture of design mix of coarse and fine aggregate concrete
How do calculate the water/cement ratio in Design mix concrete and give the procedure?
if cement — 10 cft,sand – 15 cft ,aggregates – 30 cft, there cum total = 55 cft . so 1 cft – 55 /35.28 =1.56 , why the answer is 1.56 instead of 1 .
I am an Civil Engineer, I want to know M-10 means 1:2:4 ratio ,how to find cement quantity can you tell me the procedure. Is it volumetric or weight ratio.
sir,how much percentage variation in design mix aggregate grading is allowed without changing design mix.
DOES M-20 READY MIX IS GOOD INOUGH FOR SLAB FOR BUNGLOW
Dear sir,
I just want to know how to calculate the requirement of concrete exactly with area of roof slab including beams……….. pls
simple, REQUIRE QTY=LXBXD