QAQC

Practical quality assurance and quality control notes for civil engineering materials, tests and mix designs.

Dry Lean Concrete (DLC) Mix Design – A Step-by-Step Guide

This walkthrough explains how a dry lean concrete mix is prepared for pavement base layers in line with recognised Indian and MORTH specifications. It starts by testing every material on its own, then blends them so the combined grading lands close to the middle of the permitted envelope.

Codes Referenced

  • MORTH 5th Revision
  • IRC-15
  • IRC SP-49
  • IS-2386

Step 1: Test Each Material on Its Own

Before blending begins, each constituent sample is graded on the specified IS sieves. That covers the 20 mm and 10 mm coarse aggregates as well as the fine aggregates, such as stone dust and river sand. These individual grading results become the basis for the combined mix.

Grading chart for 20 mm coarse aggregate used in DLC mix design
Individual grading of 20 mm coarse aggregate
Grading chart for 10 mm coarse aggregate and stone dust in DLC mix design
Individual grading of 10 mm aggregate and stone dust

Step 2: Blend Aggregates to the Target Envelope

After each fraction is graded, the materials are combined in a chosen proportion. The goal is to pull the resulting combined curve as close as possible to the mid value between the upper and lower limits set out in the code.

Sample Blending Proportion for DLC

  • 20 mm aggregate: 30%
  • 10 mm aggregate: 35%
  • River sand: 0%
  • Stone dust: 35%
  • Total: 100%

The blended sample is then checked sieve by sieve against the acceptable limits, comparing the average percentage passing with the specified range.

Frequently Asked Questions

What does QAQC mean in civil engineering?
QAQC stands for Quality Assurance and Quality Control. On this blog it refers to the practical checks, tests, and documentation used to confirm that construction materials and workmanship meet the specified standards before work is accepted.
Which specification codes are referenced for DLC and GSB mix design?
The DLC mix design post references MORTH 5th Revision, IRC-15, IRC SP-49 and IS-2386, and walks through individual aggregate grading followed by blending to land near the mid value of the specified limits. The GSB post covers scope of work, materials, construction operations, spreading and compacting, and mix design data.
How is a Rapid Moisture Meter (RMM) calibrated?
The RMM calibration post references IS:2720 Part-2. It explains the calcium carbide reaction principle and the step-by-step procedure of preparing divided dry sand samples so that RMM readings can be compared against actual moisture content.
What topics does this blog cover?
Posts and labels on the site cover Engineering (QAQC), Bituminous work, DLC, GSB, and Raingauge, with a dedicated TEST FORMAT page for test-related reference material.
How can I find a specific test format or post?
Use the Search This Blog box at the top of the page, browse the Labels list, or open the TEST FORMAT page from the menu to reach the reference formats.

Explore the Site

Look through the reference formats, follow the blog feed, or reach out to the author.

HomeTest FormatVisit ProfileRead CommentsSubscribe to Posts via NetvibesSubscribe to Posts via YahooSubscribe to Comments via NetvibesSubscribe to Comments via YahooReport AbusePowered by Blogger

Contact us

Whether you are checking aggregate gradation, blending fractions for a DLC base layer, or calibrating field equipment, the aim stays the same: confirm that materials and workmanship match the specified standards before work is accepted. Use the reference codes and test formats on this site as a starting point for your own quality checks.