Differences in the Temperature

Differences in the temperature range of chemical fixings

Temperature ranges and their significance. How temperature impacts design and loads

Definition temperature range

Effects of temperature on mortar performance (load level) In ETA assessments different temperature specifications are given. Relevant for the design and load comparisons are the in-service temperature ranges (= temperature in the substrate during the service life of the anchoring). The long-term temperature is calculated by 0.6 x short-term temperature (e.g. 120 °C short-term temperature ≥ +72 °C long-term temperature). The minimum temperature in the anchoring base for the installed and cured bonded anchor is fixed in the European guidelines at -40 °C. The upper value, the maximum temperature depends on the mortar and is determined by tests. A differentiation is made between the maximum long-term temperature and the short-term temperature. The long-term temperature describes the temperature in the anchoring base over the entire service life. The short-term temperature is the maximum temperature in the anchoring base that can be reached over a day / night cycle.

Lets have a look at the temperature ranges of our best in class epoxy mortar - FIS EM Plus:

Effects of temperature on mortar performance (load level)

Materials generally become more brittle on cooling and softer on heating. This also applies to our injection mortars. They become softer as the temperature rises and the load level therefore decreases. For this reason, we specify lower and upper temperature limits within which the injection mortar has its guaranteed performance.

Why are there different in-service temperature ranges?

There is no clear definition of how to determine the long-term temperatures or short-term temperatures in practice! Common temperature ranges that can be found in the EAD are 24/40 °C; 50/80 °C. However, each manufacturer can choose any temperature range and have the product tested. We are often confronted with a temperature range of -40 °C to +40 °C (max. short term temperature +40 °C and max. long term temperature +24 °C) competitors

have in their assessments. This temperature range is easily exceeded in many regions, as +24 °C more or less corresponds to room temperature. For this reason, we do not recommend designing for this temperature range.

What has to be taken into account for dimensioning and load comparisons?

According to the European Technical Assessments (ETAs), the characteristic bond strength of bonded anchors are classified to temperature ranges.
These temperature ranges describe the temperatures in the anchor base concrete and affect the load bearing capacity and the characteristic bond strength of the injection system or capsule used.
When using the C-Fix module of our Fixperience Suite, you can find the temperature range in the tab 'Substrate’.

The setting 'Long Term Temperature' and 'Short Term Temperature' can be chosen independently from each other.
The software is developed in such a way that the program always selects the appropriate temperature range of the injection system chosen.
This enables the user to select the actual temperature in its base material independently from the rigid temperature ranges shown in the ETAs.

Keep in mind

When evaluating the performance of an injection mortar, it is not sufficient to compare temperature range I of product X with temperature range I of product Y. Rather, care must be taken to select comparable temperature ranges: it may be necessary to compare temperature range I of product X with temperature range II of product Y in order to obtain a meaningful result.

For example: Be aware that temperature range I of FIS EM Plus has a higher long-term temperature than the competition (+35°C vs. +24°C). Temperature matters regarding load, especially for Epoxy mortars. A temperature of +24°C is quickly reached, so temperature range II will be applicable in most cases. Consequently, FIS EM Plus has a higher long-term temperature leading to a higher load.