ASTM C39/C39M – Compressive Strength Test of Cylindrical Specimens – A Quick Guide

Types of fracture patterns of cylindrical specimen as per ASTM C39

The compressive strength test is one of the most important quality-control tests for concrete. ASTM C39/C39M covers the determination of compressive strength of molded concrete cylinders and drilled cores having a density greater than 800 kg/m³. The test involves applying a continuously increasing axial compressive load until failure and calculating the strength from the maximum … Read more

How to Correlate Rebound Number with Concrete Strength

How to establish relationship between rebound number and concrete strength

Establishing a reliable relationship between rebound hammer numbers and the compressive strength of concrete is a crucial aspect of quality control in construction projects. This correlation serves as a valuable tool for rapid, non-destructive assessment of concrete strength in both existing and under-construction structures. The rebound hammer test offers a quick and cost-effective method to … Read more

25+ Codal Provisions from IS 516 (Part 1 / Section 1): 2021 – Testing of Hardened Concrete

25 codal provisions to remember from IS 516 (Part1Sec1) 2021

Codal Provisions from IS 516 (Part 1 / Section 1) If you are involved in construction, quality control, or civil engineering, keeping up with standard codes is crucial for safety and compliance. The Bureau of Indian Standards updated its concrete testing protocols with IS 516 (Part 1 / Section 1): 2021. This comprehensive standard outlines … Read more

Compressive Strength Test of Concrete (ASTM C39 & IS 516)

Compressive strength test of concrete ASTM C39 vs IS 516

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

HOW TO DO FLEXURAL STRENGTH TEST OF CONCRETE?

Flexural Strength Test Arrangement

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

HOW TO MAKE TEST CUBES FROM FRESH CONCRETE?

Self compacting concrete

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

FLEXURAL STRENGTH TEST OF CONCRETE (IS:516-2021)

Flexural Strength Test Arrangement

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 TEST OF FRESH CONCRETE TO MEASURE WORKABILITY (IS-1199-1959)

Slump test of concrete to measure workability

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

HOW TO DETERMINE DRYING SHRINKAGE OF HARDENED CONCRETE?

Length Comparator for measuring initial drying shrinkage of concrete specimen

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

WHAT ARE THE FACTORS INFLUENCING COMPRESSIVE STRENGTH TEST RESULTS OF CONCRETE?

Correction factor for height-diameter ratio of a core

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