For times when cast-in rebars aren’t planned and placed to connect concrete members, there aren’t many alternatives other than using injection mortar or grout. At first sight, they might look like similar technologies – still talking about chemical products surrounding a rebar, installed in a drilled hole, isn’t it? However, these two technologies are far from being similar for several reasons.

We touched on this in a previous article comparing the most popular rebar technologies. You may benchmark and compare the two technologies from different points of view, such as code suitability, productivity and reliability. Spoiler alert: Injection mortar outperforms grouts in every aspect.

Let’s deep dive into the comparison based on the regulatory framework for now.

Before we start, it would make sense to clarify a few points. Talking about grouts, we are referring to pre-dosed bi-components products that need to be mixed (manually or using a machine) by an operator. The grout will be installed by pouring method therefore it limited in vertical downward installation direction.

An example of grouting application

Talking about mortar injection systems, we refer again to bi-component products in pre-dosed cartridges (such as HIT-RE 500 V3 and HIT-HY 200-R). The mixing is carried out by a dispenser (by discarding a required number of pumps as per the product manual) The dispenser is also used for injecting the adhesive blend into the bore hole.

An example of dispenser-mixing and injection of a chemical mortar

The importance of a technically sound qualification process in place for injection mortars: ETA Approvals

When dealing with the design of critical and safety-relevant applications, there are two important tasks to be accomplished: first of all you need to define the acting loads. Secondly, you need to run a proper design to check if the capability is higher than, or at least equal to, the demand.

To be safe and compliant with the international standards used for the design of the rest of the structure, post-installed rebar applications should be carried out by a technology fully covered under these standards. Injection mortar technology from reputed brands and with third-party approvals are suitable for designing your concrete-to-concrete connections according to Eurocode. Also, we need to ensure that the application conditions such as fire is covered, if necessary.

Imagine designing a concrete-to-concrete connection, for instance, a slab-to-wall. You calculated the overall structure and reinforcement according to Eurocode 2 or Local Concrete Code. You select a grouting material has not been approved by international standards (such as TR023) for post-installed rebar application, how could you guarantee the performance of the material and ensure the force will be transferred through over time?

The answer is easy: you cannot know, we cannot simply run a design with such a grout system if the performance has not been determined specifically for post-installed rebar applications. We might be comparing apples with oranges here.

The importance of having a full qualification such as ETA in place for post-installed rebar solutions

In case you need more support to understand which qualification is most suited to your application requirement, please leave a comment on this article or post your question in our Ask section.