Setting Time Test of Concrete The setting of concrete is a gradual process, and therefore its initial and final setting times must be defined by specified measurable criteria. The penetration resistance method determines these times from the resistance offered by the mortar fraction sieved from fresh concrete. Reference ASTM C403/C403M – Time of Setting of … Read more
Concrete durability is often governed not only by its compressive strength but also by the quality of its surface zone. The outer layer of concrete is the first line of defence against rainwater, moisture and other environmental actions. A concrete surface that absorbs water rapidly may indicate poor finishing, inadequate curing, a porous surface layer … Read more
Concrete Pavement Construction Process The construction of concrete pavement involves sequential construction of subgrade, sub-base/ base and the concrete slab. These are discussed in the following. Subgrade preparation Subgrade preparation involves cleaning, earthwork (excavation or filling of soil, replacement of weak soil, soil stabilization etc.) and compaction. Where the concrete layer is laid directly over the subgrade, the subgrade … Read more
Concrete is normally selected for its strength, durability and versatility. However, some applications require another important property: high mass within a limited volume. This is where high density concrete, also known as heavyweight concrete, becomes useful. By replacing conventional aggregates with heavier natural or manufactured materials, concrete with a significantly higher density can be produced. … Read more
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
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
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 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
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
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
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