What does concrete strength mean and what is cement?

Concrete strength is the maximum level of resistance to deformation and breakage that may be caused by the loads on the concrete . As a result of applying loads in different directions on the concrete, different effects may occur. The ability of concrete to resist deformation and fracture under loads that will create pressure, tensile, bending and shear effects are defined as compressive strength, tensile strength, bending strength and shear strength, respectively. Fatigue strength is the resistance of concrete to deformation and fracture under repetitive loads. When strength is mentioned in concrete, compressive strength should be understood if other strengths are not specified. This is because concrete behaves better under compressive loads. When designing a building, the compressive strength of the concrete to be used in that building is an important criterion. The bearing capacity and cross-sectional areas of the building elements are determined according to this criterion. The main factor affecting the bearing capacity in reinforced concrete structures is the compressive strength of concrete. In addition, compressive strength is used as a universal measure in the quality control of concrete. The fact that the compressive strength is directly proportional to most of the properties of the concrete, the compressive strength test of the concrete can be done more easily than the other strength tests, the compressive strength is taken as the basis when creating concrete classes, etc. For these reasons, the most important one among the concrete strengths is the compressive strength. So, what is the cement that has a significant effect on concrete strength? If it is desired to make a general definition, the material that binds aggregates together by forming a binding paste when combined with water in the mixture is called cement . Within this general definition, there are different types of cements. Portland cements are the most widely used among them. The hydraulic binder obtained as a result of grinding Portland cement clinker together with gypsum and, if desired, any natural or artificial pozzolanic material up to 10% is called portland cement . Portland cement clinker is formed by grinding the limestone, siliceous sand and clay in certain proportions and cooking them at least until sintering . Natural and artificial substances that do not have any binding on their own, but that gain binding properties by reacting with calcium hydroxide in a humid environment and at normal temperature when finely ground are called pozzolanic substances . Blast furnace slag, fly ash, trass, acid rhyolite, trachyte and tuffs, acid basalts, fine silica sands, pumice and perlites can be given as examples of pozzolanic materials. The effect of other factors that change the quality of the cement, such as age (fresh or stale), humidity and pollution, on the compressive strength of concrete is widely known. When cement and water come together during concrete formation, each main component reacts with water separately. The reaction rate of each of these main components, the heat released during the reaction, and the contribution of the product formed as a result of the reaction to the binding of the cement paste can be different. Chemical reactions initiated by the combination of the main components of cement with water release heat. As long as these reactions continue, heat will continue to be released. Although the hydration rate of concrete is high in the first years, the hydration rate slows down as time progresses. Cement, It is a material that provides the formation of cement paste, which comes together with water at the specified mixing ratios and binds the aggregates together. Concrete mass emerges as a result of the binding dough consisting of cement, water and air combined with aggregate.