Concrete is a widely used construction material known for its strength and durability. It is composed of a mixture of cement, aggregates (such as sand and gravel), water, and often various chemical admixtures. To ensure the quality and performance of concrete, several tests are conducted at different stages, from the selection of materials to the assessment of the hardened concrete. Here are some of the most common tests performed on concrete:

1. Slump Test: This test measures the consistency or workability of fresh concrete. A cone-shaped mold is filled with concrete, and the mold is then lifted, allowing the concrete to slump. The amount of slump is measured to determine the water content and the degree of workability.
2. Compressive Strength Test: Compressive strength is a crucial property of concrete that determines its ability to withstand loads and resist deformation. Cylindrical or cubical specimens are cast and cured under specified conditions, and then subjected to a compressive load until failure. The maximum load-bearing capacity is divided by the cross-sectional area to obtain the compressive strength of the concrete.
3. Flexural Strength Test: This test evaluates the ability of concrete to resist bending or flexural stresses. A beam specimen is subjected to a load at its midpoint until failure occurs. The load at failure and the dimensions of the beam are used to calculate the flexural strength.
4. Water Absorption Test: Water absorption test determines the porosity of concrete, which is important for assessing its durability. Specimens are dried, weighed, and then immersed in water for a specified period. After removal from water, they are weighed again to measure the amount of water absorbed.
5. Permeability Test: This test assesses the ability of concrete to resist the passage of fluids, such as water or aggressive chemicals. Different methods, such as the water permeability test and the chloride permeability test, are used to measure the permeability of concrete.
6. Density Test: The density of concrete affects its strength and durability. The density test determines the mass per unit volume of the hardened concrete. It is usually performed by weighing a known volume of concrete and calculating its density.
7. Setting Time Test: Setting time is the time taken by concrete to harden and gain strength. The initial setting time and final setting time are measured using various techniques. These values are important for determining the workability and handling of concrete during construction.
8. Chloride Ion Penetration Test: This test evaluates the resistance of concrete to chloride ion penetration, which can cause corrosion of reinforcing steel. The test involves applying an electrical potential across the concrete specimen and measuring the charge passed through it, providing an indication of the chloride ion penetration.
9. Alkali-Silica Reactivity (ASR) Test: This test determines the potential of reactive silica in aggregates to react with alkalis present in the concrete, leading to expansion and cracking. Different methods, such as the mortar bar test and the accelerated mortar bar test, are used to assess the susceptibility of aggregates to ASR.

These are just a few examples of the tests performed on concrete. Other tests may include durability assessments, thermal properties evaluation, modulus of elasticity, and more. The specific tests conducted depend on the project requirements, standards, and quality control procedures in place.