Splitting Tensile Strength of Concrete Road Slabs – A Key Property for Load Capacity and Durability

Concrete pavements are continually subject to the effects of weather and traffic. These may cause tensile stresses at the top and bottom of the concrete road slabs. The resistance of the concrete slab to such effects depends on a large number of factors. In particular, the concrete tensile strength and the thickness of the concrete slab are key factors in dimensioning. In principle, it is possible to determine the concrete tensile strength directly or indirectly. For exper-imental reasons, the indirect determination of the tensile strength is the most frequently used method in practice. In this manner, the generally applicable splitting tensile strength testing method for simple and effective concrete tensile strength testing was further developed and modified for road construction 10 years ago. Here the upper and lower discs of a test cylinder or drill core are tested. The evaluation ensued statistically at the lower 5% quantile. This method and the testing device are precisely described in a national test specification. Initial applications of this testing method were undertaken in recent years as part of major projects (PPP models), in which the splitting tensile strength thus determined represents the standard input value for the computational dimensioning. Experience to date reveals that the test statistical spreading of the splitting tensile strength and compressive strength tests exhibits approximately the same order of magnitude. In order to determine the precision of the testing method in a sound manner, a round robin test with 13 testing laboratories and 8 test lots was performed in Germany and statistically evaluated. In addition, the development of the compressive strength and splitting tensile strength was ascer-tained over time in a further research project. Fatigue tests were also performed here to take ac-count of the fatigue behaviour, in order to establish a correlation to the statistical splitting tensile strengths. The aforementioned research project was first and foremost aimed at verifying the goal, precision and practical suitability of the testing method. This is particularly important because the statistical determination of the splitting tensile strength represents a simple testing method in practice. Basi-cally, it is also envisaged to make use of the mechanical splitting tensile strength parameter as a test quantity for conventional construction projects in the future.