Don’t worry, there’s plenty of sand for infrastructure projects in perpetuity. Every time we have an ice age, we get a lot more sand to work with.
According to the world’s geologists and climate scientists, a new ice age is not likely any time soon, making sand from nature a limited resource. Are there any alternatives?
Pioneers in machine sand
One of the players that has taken the time to crack the code behind sustainable alternatives is NCC. Together with their customer Unicon, they have developed recipes for concrete where natural sand is completely replaced by machine sand.
By using a washing plant and wind screening plant, they set a goal to create a machine sand with optimal properties in concrete, as well as to utilize all the pulp extracted from their quarry.
– The learning curve has been steep. “We first tried to copy the basket for natural sand, but it gradually became clear that it would not work, as the machine sand has different properties than natural sand,” writes Frode Jørgensen, Director of NCC Stone Materials in Norway, in a blog post on the company’s website.
After a few years of trial and error, they eventually reached the goal of creating a 100% curve with machine sand that meets all quality requirements for structural concrete, fluid concrete and shotcrete.
The path to more profitable mass balance
As machine sand comes from crushed stone, it is not a large enough volume to meet the world’s need for concrete aggregates, but it appears to be a very good supplement, both for the environment and to achieve a profitable mass balance in the plant.
One example of improved mass balance is at NCC’s plant in Skien, where the company produces cubed machine sand that they believe has such a smooth curve that it performs better than natural sand when it comes to concrete aggregates. That’s because you no longer need to account for the variations of natural sand.
In Bergen and Larvik, the company uses washing plants to utilize the fines in the crushed stone plants. The difference is that washed machine sand has a fixed, but adjustable, amount of fines. After the washing process, they assemble a basket in a mixing plant and deliver a pre-calibrated machine sand.
Read more:
How much potential is there in eco-stations for the construction industry?
– In the future, we will invest further in classification facilities at our sites, so that we can utilize 100% of the masses we extract. After several years of work, we can confirm that machine sand is now part of our product range,” says Jørgensen.
How to get more tenders in the future
In April, the Norwegian Public Roads Administration announced that for the second year in a row they had successfully implemented CO2 weighting in asphalt contracts, and they state that it was decisive for which contractors were awarded the contracts.
It is not unlikely that similar requirements will also apply to concrete supplied for large Norwegian construction projects, as this has been going on for a long time elsewhere in Europe.
On the public procurement page, they cite an example where London’s bid to host the 2012 Olympics included a plan to identify, source and use environmentally friendly materials.
In the technical specifications, the requirement was that the bidders should at least meet the following objectives:
1. Ensure that the construction products (in value) consisted of at least 20% recycled content
2. Ensure that 25% of the aggregate used was recycled
3. 50% of the materials (by weight) should be transported to the site in a sustainable way, i.e. by rail or water
4. Use of energy-efficient and low-emission vehicles in the area
Great results
The project owner at the London Olympic Stadium worked with the concrete supplier and supply chain to develop sustainable concrete mixes. This resulted in approximately 170,000 tons (almost 22%) of recycled and secondary aggregates.
In the future, we will invest further in classification facilities at our sites, so that we can utilize 100% of the masses we extract.
Frode Jørgensen, Director of NCC Stone Materials in Norway
Focusing on the reuse of materials is something that will undoubtedly take up more space in the assessment of tenders, and can in some cases be decisive in determining who wins.
If we go back to the question this blog post started with:
Is machine sand really something you should care about?
The answer is yes.
Starting with environmentally friendly masses?
It seems machine sand and other environmentally friendly materials are here to stay. If you have questions on how to get started, we have an agency for washing systems from CDE Global, which are used by
- Gunnar Holth Grusforretning
- Feiring Bruk
- Field crushed stone
Read more about the facilities that lead the industry here:
Anleggsmaskinen.no/washing-system-provides-success