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

Expansion Joint in Concrete – What, Why & How

Expansion Joint in Concrete What Why and How

Concrete may look rigid and immovable, but a concrete structure is continuously subjected to dimensional changes throughout its service life. Changes in temperature, drying shrinkage, creep, moisture and other environmental effects can cause concrete to expand, contract or deform. If these movements are restrained, stresses can develop within the concrete. When the induced tensile stress … 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

Sustainability of Concrete: How Can We Make Concrete More Sustainable?

Sustainability of Concrete How to make concrete more sustainable

Sustainability of Concrete Concrete is everywhere. From foundations and retaining walls to bridges, dams, high-rise buildings, industrial plants and roads, modern infrastructure would be almost impossible to imagine without it. But concrete has a sustainability problem. The issue is not really concrete itself. The biggest environmental impact comes from the cement used to make concrete—particularly … Read more

How to Determine the Optimum Dosage of Superplasticizer

How to determine optimum dosage of superplasticizer using marsh cone test

Determining the optimum dosage of a superplasticizer is essential for achieving the desired workability, strength, and durability of concrete while avoiding unnecessary admixture consumption. Two of the most widely used laboratory methods for this purpose are the Marsh Cone Test and the Mini Slump Cone Test. In this article, you will learn both methods step … Read more

Dry Material (Solid) Content Test of Chemical Admixtures

Solid content test of chemical admixture

Solid Content Test of Admixture Chemical admixtures have become an essential component of modern concrete, particularly when high workability is required without increasing the water content. Depending on the product, admixtures are supplied either as liquids or as powders. Solid content of admixture impacts its properties. Measuirng solid content helps in following ways. Test Summary … Read more

Strength Activity Index Test for Pozzolanic Material

Strength Activity Index Test for Pozzolanic Materials

Strength Activity Index (SAI) Test (ASTM C311/C311M) Ordinary Portland Cement (OPC) production is highly energy-intensive and contributes significantly to carbon emissions. To reduce cement consumption and improve sustainability, supplementary cementitious materials (SCMs) are incorporated into concrete. Many of these materials exhibit pozzolanic properties, meaning they react with calcium hydroxide [Ca(OH)₂], a by-product of cement hydration, … Read more

Silica Fume (Microsilica) in Concrete: Benefits, Working Mechanism, Dosage, Challenges

Silica fume of Microsilica in concrete

Concrete is no longer just a mixture of cement, sand, aggregates, and water. Modern structures such as high-rise buildings, long-span bridges, marine structures, metro projects, and industrial plants demand concrete that is stronger, denser, and far more durable than conventional concrete. One material that has completely changed the way high-performance concrete is produced is silica … 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