Dincel meets self compacting concrete

The test walls Dincel created using their formwork and self compacting concrete, courtesy of Dincel

The team at Dincel recently undertook testing to evaluate the performance of self compacting concrete in Dincel formwork shells, with a focus on further improving the Dincel construction process.

Roads & Infrastructure speaks to Dincel director, Berkay Dincel about the results.

Self compacting concrete (SCC) is designed to flow into a mould or area and compact before it sets, filling the area completely with concrete.

Opposed to traditional concrete, SCC can spread out and fill any gaps, holes or voids by itself without the need for vibration VicRoads Technical Note 73 states that the concept of self-compacting concrete was first developed in Japan in the mid to late 1980s.

“A well designed and produced SCC has the capability to flow under its own weight through and around congested steel reinforcement fully encapsulating it, completely filling the space within the formwork, without any loss of strength, stability or homogeneity, while still achieving the same outcomes of good compaction,” the note outlines.

The technical note outlines three key performance requirements for SCC being; a good filling ability so the concrete can easily flow through the formwork, quality passing ability with aggregates small enough to flow around reinforcement, and segregation resistance

“SCC offers improved quality and durability compared to conventional vibrated concrete, provided it is considered as part of the whole construction process including the detailed design stage of a project,” the note states.

As part of its research and development practices the team at Dincel have been investigating how self-compacting concrete performs inside Dincel permanent formwork
Roads & Infrastructure spoke to the Dincel team about their findings.

A DINCEL FORMWORK RECAP
Dincel walling profiles are connected with a simple snap lock joint and filled with concrete. Once filled, the formwork stays in place and acts as a waterproof protective membrane to create a concrete wall.

Designed specifically for heavy civil solutions the Dincel 275 formwork shell consists of an internal cylindrical ring which is unique. It gives the wall additional strength and in some cases steel reinforcement bars may not even be required.

Berkay Dincel, Director of Dincel Construction System, says when the team created the Dincel 275 formwork they wanted to explore if they could create a wall solution for civil applications without any reinforcement at all.

To ensure that the system is structurally adequate for use without steel reinforcement, Dincel partnered with the University of Technology Sydney (UTS) for extensive testing. Tests were completed in line with Australian Standard 3600:2018 (Appendix B) for concrete structures.

“We tested the walls with mass concrete inside and then with synthetic fibre reinforced concrete, without the use of steel bars,” Dincel says.

The test results and applications were certified by UTS as compliant with the National Construction Code.

Traditionally, Dincel formwork shells have been filled with standard concrete. One of the main benefits of the solution is the speed at which Dincel walls can be constructed. Though, with the use of SCC the team found installation of Dincel walls could be sped up even further as the need to use a vibrator is removed.

SCC is also a proven and recognised method of eliminating air voids within walls, so there can be significant benefits from a quality assurance point of view.

TESTING SCC WITH DINCEL FORMWORK
The Dincel team wanted to go further and explore whether they could create void-free concrete walls by using self- compacting concrete inside the unique Dincel 275 formwork, as well as the Dincel 155 and 200 formwork.

For this Dincel set up three different tests using walls made from Dincel formwork, with varying amounts of reinforcement. The tests were set up to see how the concrete could travel and compact within each wall.

The three walls differed in thickness, height, and length, the first had no steel reinforcement and the last wall was a 5.2 metre tall Dincel 275 wall with a significant amount of vertical and horizontal steel reinforcement bars.

Dincel engaged a NATA registered independent expert to observe these tests and verify the method and results achieved. Each test was set up so the SCC was poured in one location on the wall. This was to determine if the concrete would travel from one end of a wall to another or even around corners and still achieve adequate compaction.

“If you have a concrete wall with voids in it you can get structural, fire, acoustic and waterproofing non-compliances. So, it was important for us to find out that self- compacting concrete did not leave voids in our formwork, even under worst-case conditions” Dincel says.

When the team later removed the set concrete from the Dincel walls, as you can see in the lefthand picture, there were no voids or segregation to be found.

“With self compacting concrete not only are you getting the benefits of the Dincel formwork system which include speed, cost savings, enhanced durability. That is coupled with the assurance you aren’t getting any air voids in the wall,” Dincel says.

The Dincel team were also impressed with the performance of the Dincel formwork profiles in the trial, as self- compacting concrete can put a lot of pressure on formwork.
“Dincel snap-lock joints were really effective in the test. Self compacting concrete is always looking for somewhere to move so it was great to see how the formwork contained the concrete,” he says.

“Self compacting concrete is available from many concrete suppliers in the industry and we really wanted to demonstrate how the product is something that can provide a real benefit when paired with Dincel formwork on civil projects.”

This story originally appeared in the May edition of our magazine. To read the magazine, click here.