Bending Drain

The Bending Drain, also known as the “Curling Profile Apparatus,” adheres to the EN 13892-9:2018 standards for testing screed materials’ dimensional stability. With this apparatus, you can measure the shrinkage and curling of building materials. Additionally, it allows for the simulation of real-world floor heating using built-in electrical heating.

High-precision measurements are ensured by two static abutments and a robust U-shaped steel baseplate. A neoprene foil between the formwork and the material prevents friction and blockage, even when using expanding materials. The formwork remains static, independent of the mortar beam, which is supported by two well-defined points.

The Bending Drain features both Intra- and Internet connectivity, along with an integrated data logger. No special PC is needed during measurements, as the instrument is fully controlled via your network browser software, such as Internet Explorer or similar programs. Data is stored on non-volatile memory for weeks or months, and with a single click, you can load the data directly into your Excel worksheet over a network. Data transfer is also possible using a removable Compact Flash card.

Multiple Bending Drains can be integrated into your network, each operating independently. Two high-resolution LVDTs with a 5mm stroke and 0.3µm resolution provide highly reliable results.

An RTD measures the temperature at the bottom of the formwork, while a thermocouple embedded in the specimen measures its temperature. Additionally, a moisture/temperature sensor monitors the humidity and temperature on the specimen surface.

For floor heating, you can program a temperature profile over time. For example, you can increase the temperature from 20°C to 60°C after 6 days, maintain it for 3 days, and then reduce it back to 20°C.

Measurement Example

Below is a typical data plot. The x-axis represents time in days, while the y-axis shows temperature in °C and length change in microns. After 4.5 days, the floor heating was activated. The green line indicates the temperature at the bottom of the specimen, and the blue line represents the temperature in the core of the specimen. The red line shows the bending, and the black line indicates the length change. This measurement was conducted at the Hasit Laboratory.