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.
Please send me mix design procedure for aggregate size 80 mm.
sir, i need the compressive strength of various concrete mixes at 3 days
Is water weight calculate in 2406 kg (1cube meter) ?
Give me
Aggreegate : ___kg
Sand : ___kg
Cement : ___kg
Sir
My name is ankith I have a doubt what are the differences between M20 and M25 grade tell me about that
Please tell me how much cement,10mm ,20 mm , send & water be used in m20 mix please reply as soon as possible
i have doubt in estimated water content and how to find the percentage of sand is to be used.
how to calculate below result kindly explain me
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
Plz explain how 320 kgs of cement is used instead of 400kgs of cement for m20 concrete in kpwd sr …
I need a brief description about mix design details.please send me
which type of concrete mix design sir…?like M35,M40 etc…
I need a brief description about mix design details.please send me
which type of concrete mix design sir…?like M35,M40 etc…
A mix of M-80 Grade suitable for pumped concrete is to be designed with the following materials and detail.
1. OPC 53 Grade, 7-day strength 52.5 N/mm2, Spgr 3.15
2. Silica Fume Specific Gravity 2.20
3. Standard deviation for the mix 5.0 N/mm2
4. Grading and properties of river sand and 12.5 mm crushed aggregate are given in Table-1
5. Superplasticizer based on modified Polycarboxylate, specific gravity 1.06, liquid pH 6.0. With the given set of materials, it was found that at a dosages of 2.5 % bwc it gives a reduction of 30% of water for the required slump of 100 mm after one hour at the average day site temperature of 37 degree C.
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Filed under Concrete Engineering, Mix Design, Research Papers | 1 Comment
Mix Design For Concrete Roads As Per IRC:15-2011
By
Kaushal Kishore, Materials Engineer, Roorkee
ABSTRACT:
The stresses induced in concrete pavements are mainly flexural. Therefore flexural strength is more often specified than compressive strength in the design of concrete mixes for pavement construction. A simple method of concrete mix design based on flexural strength for normal weight concrete mixes is described in the paper.
INTRODUCTION:
Usual criterion for the strength of concrete in the building industry is the compressive strength, which is considered as a measure of quality concrete. However, in pavement constructions, such as highway and airport runway, the flexural strength of concrete is considered more important, as the stresses induced in concrete pavements are mainly flexural. Therefore, flexural strength is more often specified than compressive strength in the design of concrete mixes for pavement construction. It is not perfectly reliable to predict flexural strength from compressive strength. Further, various codes of the world specified that the paving concrete mixes should preferably be designed in the laboratory and controlled in the field on the basis of its flexural strength. Therefore, there is a need to design concrete mixes based on flexural strength.
sir, in 1.REQUIREMENTS…..b)durability requirements……ii)minimum cement content=300kgs/cum
please let me know how/on what basis you have taken minimum cement content=300kgs/cum
Sunil kumar kindly check is 456 table no 5 page no 20 u will get ur answer
Sir pl clarify the limits for crushed sand passing below 150 micron is revised as 0 to 20 but in all in aggregate it is kept same i. e. 0 to 6 why not limits revised
need test sieve analysis formula range size 0.425 – 0.85 mm Effective size and Uniformity coefficient
Sand me design of concrete m30 to m80
i wanted to know the suitable proportion of contents of basalt crushed stone which can be used for construction purpose.
sir, send me a mix design of C30 & C35 of concrete.
I would like to know all the classes of concrete and their corresponding proportions. Secondly, how is the volume of entrapped air estimated during a concrete mix design? Thnx
Hi sir,
This hemant i am new in this field plz help me out and i just want to know, the required material for M20 Grade, 300x300x450 high rcc block,
like : Cement grade, & Qty, M20 Aggregate, Qty, Sand Qty. and required water..
Thanks
Hemant
Please do L×b×h.
how much mm sand using for 2 coat plastering?
what is the reason behind using 53 grade cement in m20 concrete?