Steps Involved in Mix Proportioning as per IS 10262:2009 (with solved example)

Mix Proportioning as per IS 10262:2009
Mix Proportioning as per IS 10262:2009

Steps Involved in Mix Proportioning as per IS 10262:2009 (with solved example)

Mix Proportioning as per IS 10262:2009
Mix Proportioning as per IS 10262:2009

 

General Steps Involved in Mix Proportioning

Step 1. Choice of Slump

  • Stiffest possible consistency that can be easily placed and compacted without segregation
  • Pumping are typically designed for 100 mm to 150 mm slump

Step 2. Choice of Max. Size of Aggregate

  • For given volume of coarse aggregate,

Step 3. Estimation of the mixing water content and air content

Depends on ,

  • The maximum particle size of the aggregate
  • Entrained air

Step 4. Selection of water-cement ratio

  • Develop the relationship between strength and water-cement ratio for the materials to be used actually
  • Checked for durability criteria

Step 5: Calculation of the cement content

  • Computed by dividing the mixing water content by the water-cement ratio
  • Adjustments to Min. cement content for aggregates other than 20 mm nominal max. size, as per IS 456: 2000

Step 6: Estimation of the coarse aggregate content

  • Estimated from Maximum aggregate size & fineness modulus of fine aggregate
  • Dry weight obtained by multiplying with Dry Rodded unit weight
  • Range in proportions of materials used in concrete, by absolute volume

Step 7: Estimation of the fine aggregate content

  • Weight Method
  • Absolute volume Method

Step 8: Adjustments for the aggregate moisture

  • Mixing water reduced depending on Free Moisture
  • Amounts of aggregates increased accordingly

Step 9: Trial batch adjustments

  • Mixture satisfying the desired criteria of workability and strength is obtained
  • Mixture proportions of the laboratory-size trial batch are scaled up for producing full-size field batches

Data required for Proportioning

Road Aggregates

  • Grade Designation
  • Type of Cement
  • Maximum Nominal size of Aggregate
  • Minimum Cement Content
  • Maximum w/c ratio
  • Workability in terms of Slump
  • Exposure conditions
  • Method of placing
  • Type of aggregate
  • Maximum cement content
  • Test data of Materials
  • Admixture type and condition of use if any

Mix Proportioning as per IS 10262:2009

  • Target strength for mix proportioning
  • Selection of w/ c ratio
  • Selection of water content
  • Corrections in water content
  • Calculation of cement content
  • Proportion of volume of coarse aggregate and fine aggregate content
  • Corrections
  • Mix calculations

Design stipulations for proportioning

  • Grade designation   : M20
  • Type of cement   : OPC 43 grade, IS 8112
  • Max. nominal size of agg.   : 20 mm
  • Minimum cement content  : 320 kg/m3
  • Maximum water cement ratio   : 0.55
  • Workability   : 75 mm (slump)
  • Exposure condition   : Mild
  • Degree of supervision  : Good
  • Type of agg.   : Crushed angular agg.
  •  Maximum cement content   : 450 kg/m3
  • Chemical admixture   : Not used

REFER last part of ppt for worked out example and better understanding

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About Anand Paul 253 Articles
...an Engineer and Tutor. Anand Paul is a bridge engineer at ch2m Global Design Center, Hyderabad. He is responsible for regional and local design projects. Committed to quality and timely delivery, he has been assigned multiple domain projects in Middle and India. Being a programmer, he is leading in-house spreadsheet development team. Apart from his routine, he runs CivilDigital.com, an exclusive Civil Engineering website.

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