Welcome
Querkraft Testing: Helping to develop CONCRETE knowledge.
Introducing the Nogueira Torsion Test (NTT): One device, three new ways to test concrete.
Querkraft Testing Mission
The mission of Querkraft Testing is to develop new devices to test concrete and other materials.
Concrete is one of the most important construction materials used in Civil Engineering. Concrete is used in the construction of dams, highways, buildings, bridges, tunnels and many other structures. Even when concrete is not the main structural material, e.g. in masonry and steel structures, concrete is frequently used in secondary structural members, such as foundation blocks and slabs. Every year, billions of tonnes of concrete are produced and used around the world. Although widely used in the construction industry, concrete is a very complex material whose properties are not easily evaluated. Concrete is granular, has voids and microcracks, the aggregate grain-size distribution varies depending on the mixture design, and concrete strength depends on loading conditions. Concrete properties are directly affected by factors such as: water-cement ratio, aggregate type and distribution, air entrainment, curing conditions, cement type, and admixtures. Concrete behavior under stresses is complex, while relatively strong under uniaxial compression, concrete can be considered weak under tensile stresses (approximately 10% of the compressive strength) and the assessment of the tensile strength can be a complicated task, with results depending on the methodology used. Evaluation of concrete shear strength is also challenging because it is difficult to apply shear to concrete specimens without spuriously introducing other stresses.
About querkraft testing
Querkraft Testing mission
Concrete helical tensile strength
Querkraft Testing mission
The mission of Querkraft Testing is to develop and disseminate the use of new devices and techniques to test concrete and other construction materials.
Concrete shear strength
Concrete helical tensile strength
Querkraft Testing mission
The Nogueira Torsion Test can be used to easily evaluate concrete shear strength using notched cylindrical specimens.
Shear strength of interfaces
Concrete helical tensile strength
Concrete helical tensile strength
The Nogueira Torsion Test device allows the evaluation of shear interface bond strength between concrete and a substrate using cores.
Concrete helical tensile strength
Concrete helical tensile strength
Concrete helical tensile strength
The Nogueira Torsion Test introduces a new way of measuring concrete tensile strength. With the device, helical tension can be used to evaluate concrete tensile strength using cylinders.
