ABSTRACT
This chapter describes the most common test methods used to assess concrete strength and then discusses the factors influencing the results obtained from them. It considers the cracking and fracture processes taking place within the concrete. It briefly discusses strength under multiaxial loading situations. The simplest compressive strength test uses a concrete cube, and this is the standard test in the United Kingdom and many other countries. An alternative test, which at least partly overcomes the restraint problem, uses cylinders; this is popular in North America, most of Europe and in many other parts of the world. Testing cylinders has one major disadvantage; the top surface is finished by a trowel and is not plane and smooth enough for testing, and it therefore requires further preparation. The chapter looks at the relationships between the strength of concrete and the many factors that influence it, and introduces an extremely important aspect of the concrete's structure.
