The standard lays down a method for ？ determining breaking force. By breaking force is meant the force required to pull a concrete cylinder, with dimensions as given in figure 1, to breaking. The cylinder can be drilled after the concrete has hardened. On horizontal surfaces, cylinders can be formed using a sleeve in the fresh concrete. The sleeve is put down after the surface has been cast. The method can be used to assess the concrete strength in finis ed structures when the values are calibrated against concrete with known compressive strength and with the same composition as the concrete on which the compressive strength is to be assessed. The relationship between the force and the concrete's tensile strength can then usually be expressed as a linear function. The method can also be used to determine adhesion in concrete joints. The test report must then state the height of the specimen and whether the break has occurred in the joint or not. The fracture test can be used to determine whether the construction has achieved sufficient strength in connection with e.g.:
——prestressed concrete (pre-stressed or post-stressed) - form demolition - protection against harmful frost - the end of the curing process The method cannot be used now ？r the concrete temperature is below 0 ℃. The number of test locations and the age of the concrete at the time of testing are not specified in the standard.