Ironworks: Repairing roads the right way

Ironworks: Repairing roads the right way

When you think about repairing roads the right way, this can mean many things. The focus points we will be covering in this article is on the importance of the Iron Works reinstatement system. So currently, there is an issue or ongoing challenge around the country regarding this. Many, many local authorities are reporting challenges with failing ironworks.

So it's crucial we take a step back and understand the reason for those failures. There are  various products and great systems being used in the industry today. So why are all these ironworks still failing?

There are five key reasons that we've identified in conjunction with local authorities and experts in the industry as to why ironworks are failing. Here in this article, we will be going over these points.

  1. The bedding mortar depth
  2. Using Alternative products to prop the corners of the ironworks
  3. The ironworks need to be set at the right level
  4. The backfill system
  5. The ironwork system is open to traffic too soon

Ironwork structure from meon

Firstly let's look at the bedding mortar depth within the ironwork system. There are some discussions on how much bedding mortar should be placed underneath the number, which should be a maximum of 25mm. This is highlighted in the CD534 Chamber tops and Go talks road drainage systems.

Bedding mortar systems are designed to reach a certain compressive strength with an optimum bedding thickness. When you have too much bedding mortar, you will then find that the product will start to slump during the application process, which can lead to sections of the frame not being fully supported. In addition to this, the system becomes weaker when it passes the optimum application depth, which can lead to failures over time.

The second point is when you use alternative products to prop the corners of the ironworks to help set the finished height. Whilst this may be a common practice across the industry, it is not the right thing to do. You might prop up the corner of the ironworks using part of brick or even a piece of wood. This element has been placed in dry, and then the bedding mortar placed around it, leaving a weak point in the corners where they're not fully supported by mortar.

In this situation, if you were to lift that frame after you've applied the bedding mortar, you would find that it would have voids underneath the ironworks. Therefore, it's critical that no alternative materials are used within the ironwork bedding mortar system. Using the correct bedding depth within the reinstatement removes the requirement to prop up the corners of the ironworks.

The third point is where the ironworks need to be set at the right level. You have the carriageway level, and then you have the ironworks level. It is important that they are in the same plan, certainly within a few mm. Additionally, if you have to lift the ironworks due to situations underground, then you create a ramp into the carriageway, rather than having a sudden step as you come into the ironwork.

If  the ironworks is too high or too low, this has an impact on the longevity of the ironwork system. If it's too high, you're going to get the impact of the tyres hitting on the corner of the rim. If it's too low, you also get the impact of tyres as they drop down onto the work cover, which causes shock waves to penetrate down throughout the system.

The fourth point is the backfill system, which is used for surrounding the ironworks after you've completed the bedding system. Often common practice in the industry is to find a very simple, maybe cost-saving, backfill concrete to go around the ironwork. Whilst that backfill concrete might well be a very good backfill concrete is not necessarily the correct type of concrete to use for backfill around ironworks.

Backfill concrete around an ironwork system needs to achieve a minimum of 20 newtons per millimetre squared compressive strength before it's open to traffic. That needs to continue then to gain strength as you move forward. Using conventional rapid set concrete is not going to achieve those kinds of strengths within the given time frame.

The fifth point is an industry-wide problem. The systems are open to traffic too soon. One of the key reasons why this is a challenge within the industry is that the installers are under pressure to deliver, sometimes up to four different ironworks within a single shift. This gives them the maximum window of maybe two to two and a half hours to do an application or an installation of an ironwork. This is not sufficient time, with standard systems, to achieve the required compressive strength of the bedding system and the backfill concrete before it's open to traffic.

Parts 2 and 3 coming soon, but if you want to know more about how Meon's products can help the future of better ironwork reinstatements then get in touch today on 02392 200 606 or email us at