Storing of Aggregate on Site Store aggregate at site on a hard dry and level patch of ground If such a surface is not available then prepare a platform of planks or old corrugated iron sheets, or a floor of bricks, or a thin layer of lean concrete so as to prevent contamination with clay, … Read more
Generally we specify workability of concrete in terms of its slump test value. But sometimes it is also specified by another test called compaction factor. The relation between slump and compaction factor is roughly as follows. Relation Between Slump & Compaction factor Workability Slump in mm Compaction factor Very stiff – 0.70 Stiff 0 to … Read more
A concrete is said to be of good quality, if it is strongest, densest, most workable and most economical for the job for which it is prepared. Amount of cement used in concrete should be low and that of aggregate should be high. If the following general requirements are fulfilled, then we can produce the … Read more
Grading Limit of All in Aggregate Sieve Size Percentage of Passing For All-in-Aggregate 40 mm Nominal Size 20 mm Nominal Size 80 mm 100 – 40 mm 95 – 100 100 20 mm 45 – 75 95 – 100 4.75 mm 25 – 45 30 – 50 600 micron 8 – 30 10 – … Read more
What is Fineness Modulus of Aggregate? Fineness modulus is an empirical factor obtained by adding the cumulative percentages of aggregate retained on each of the standard sieves ranging from 80 mm to 150 micron and dividing this sum by 100. Why to Determine Fineness Modulus? Fineness modulus is generally used to get an idea of … Read more
Reference IS: 650 – Standard sand for testing cement – specification Standard Sand Standard sand is used to assess the quality of cement, lime, pozzolana and other mineral admixture used in construction industry. Previously it was imported from U.K. Now it is available at Ennore, Madras. Characteristics Standard sand shall be of quartz material Colour … Read more
Rules of Thumb on Concrete Mix Adding 4 liters of water to 1 cubic meter of freshly mixed concrete will: Increase slump about 25 mm Decrease compressive strength about 1.5 to 2.0 N/mm2 Increase shrinkage potential about 10% Waste as much as ¼ bag of cement If Freshly Mixed Concrete Temperature Increases 1 degree Celsius: … Read more
Specification For Mechanical Properties of High Strength Deformed Bars & Wires Reference IS-1786-2008-High strength deformed steel bars & wires for concrete reinforcement Type 0.2% proof stress/ yield stress, Min, N/mm2 0.2% proof stress/ yield stress, Max, N/mm2 TS/YS ratio Elongation, %, Min, on gauge length 5.65√A, where A is the cross-sectional area of the test … Read more
Our aim is to mix the fine aggregate & coarse aggregate in such a ratio so that the final combined aggregate gives the specified or desirable surface index. Follow the below mentioned steps to find the proportion of fine to coarse aggregate. Procedure Calculate the total surface index of fine aggregate (let it be x) … Read more
Total Surface Index of Aggregates In my previous post I discussed about surface index of aggregate for individual aggregate grading. But in actual practice we use combination of different aggregates having different sizes. So now the question that comes to our mind is whether we can represent surface index of mixed aggregates or not. The … Read more