Equipment for tensile testing of fresh concrete

摘要

The development of equipment suitable for measuring tensile stress-strain curves on fresh concrete is described. With such weak materials, it is essential to eliminate friction effects and this is achieved by the use of air-bearing Plates. The objective of the new equipment is to enable data to be obtained to defined the rapidly changing tensile Stress-strain performance in the first 6 h after water is added at the mixer. This information is important for Understanding plastic shrinkage cracking. The equipment is also being used to investigated early-age internal Cracking problems which have been observed with high-strength concrete and which are related to the internal Tensile failure stain of the cement paste. Some typical tensile stress-strain curves obtained using the equipment are Shown for two types of concrete.