On almost every construction project, thousands of concrete cubes or cylinders are cast and tested. Yet obtaining an accurate result involves much more than simply placing a specimen in a compression testing machine. Factors such as specimen preparation, curing conditions, machine calibration, loading rate, and even the exact age of the specimen can significantly influence … Read more
FLEXURAL STRENGTH TEST OF CONCRETE Objective To determine the Flexural Strength of Concrete, which comes into play when a road slab with inadequate sub-grade support is subjected to wheel loads and / or there are volume changes due to temperature / shrinking. Reference Standards IS: 516-1959 – Methods of tests for strength of concrete Equipment & … Read more
Making of Test Cubes From Fresh Concrete IS-456 has laid down the acceptance criteria of quality concrete. In all the cases, the 28-days compressive strength shall alone be the criterion for acceptance or rejection of the concrete. 7 days compressive strength of concrete can be carried out in order to get a relatively quicker idea … Read more
Objective To determine the Flexural Strength of Concrete, which comes into play when a road slab with inadequate sub-grade support is subjected to wheel loads and / or there are volume changes due to temperature / shrinking. Reference Standards IS: 516 (Part 1/Sec 1) : 2021 – Hardened Concrete – Methods of Test Part 1: Testing … Read more
Slump Cone Test of Fresh Concrete Object This test is performed to measure consistency or workability of fresh concrete, where the nominal maximum size of aggregate does not exceed 38 mm using slump test apparatus. Reference Standards IS : 1199 – 1959 – Method of sampling and analysis of concrete. Equipment & Apparatus Slump cone (Height … Read more
Aim This test method describes the procedure for determining the drying shrinkage or change in length of concrete specimen due to changes in moisture content. Apparatus A length measuring apparatus incorporating a dial gauge capable of measuring the length accurately to 0.005 mm. (see fig shown below) Drying oven capable of maintaining a temperature of … Read more
Factors Affecting Strength Test Results of Concrete Compressive strength is the most important property of concrete. The compressive strength of concrete is determined in the laboratory in controlled conditions. On the basis of this test result we judge the quality of concrete. But sometimes the strength test results vary so widely that it becomes difficult … Read more
Aim To determine volume of concrete per batch, where nominal maximum size of aggregate does not exceed 38 mm. Apparatus Balance – Sensitive to 0.01 kg Tamping bar – Length 38 cm, Weight 1.8 kg Cylindrical mould – Dia = 250 mm, Height = 280 mm, Capacity = 0.01m3 Step by Step Procedure to Calculate … Read more
Sampling of Fresh Concrete To ensure it is representative of the whole truck load, a standard sample consists of scoopfuls taken from different parts of the batch and collected in bucket. Scoopfuls must be taken through the moving stream, as the load is discharged, sampling the whole width and depth (not just the top part). … 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