Avoiding Concrete Segregation In Walls Leading To Cold Joint Problems At Wall To Slab/Footing Junctions
Published 12 October 2022
The Unresolved Problem.
Water leakage at the cold joint between a wall and slab/footing due to unavoidable segregation.
The Reasons Why
Over the past 12 months the Dincel Group has conducted extensive AS3735 waterproofness tests with excellent results. Learnings from this testing have revealed that irrespective of using self-compacting concrete (SCC) or conventional concrete in permanent formwork systems*, besser blocks or conventional steel/plywood formwork, segregation is largely unavoidable under any circumstance.
With conventional formwork use, segregation is usually associated with the free fall of aggregates from height. In the case of permanent polymer formwork systems, the internal webs have perforations that work like an elephant’s trunk which stops the free fall of aggregates and as such eliminates segregation.
Observations by Dincel have, however, revealed that there is another reason for concrete segregation - the concrete sitting within the pump hose before the commencement of concrete pouring.
The concrete waiting within the pump hose loses cement paste, leaving greater accumulation of coarse aggregate. The longer the wait time to start concrete placement the worse the segregation of aggregate from the cement paste.
Practically, it is not possible to disperse and mix the already segregated concrete at the bottom of the wall - even with good vibration practices. The reality is that even expert vibration practices will only begin at least after the placement of a few hundred millimetres of concrete depth.
The Solution.
The only way to avoid this problem is to discharge the already segregated concrete before beginning with the placement of concrete. It need only be a minimal amount that is discharged to waste, but this will ensure a cohesive wall to slab/footing junction.
 | The concrete waiting within the pump hose at the kink created by the hose clamp loses cement paste, leaving greater accumulation of coarse aggregate. |
 | Prior to starting concrete placement, discharge the segregated concrete. |
 | Concrete that was sitting within the pump hose discharged into a barrel prior to the commencement of the concrete pour. |
* polymer, fibre-cement, double-precast wall
Recent Articles
-
Does Your Insurance Cover Leaking Walls And/Or Mould/Mildew?
Published March 2024 -
Your Engineer can eliminate the need for horizontal bars with Dincel
Published March 2024 -
Does Your Building Comply With Mould/Mildew Requirements of NCC-2022 & NSW Water Management Act?
Published January 2024 -
Beyond British Standard BS8102:2022
Published December 2023 -
Celebrating a Dincel milestone
Published December 2023 -
A Q&A With Steve Darwell, Chief Operating Officer at Dincel Structural Walling.
Published August 2023 -
Fire Compliance - Report by Grove & Wynn-Jones
Published August 2023 -
Spotlight on the Dincel Waterproof Basement Solution
Published August 2023
Archive
Does Your Insurance Cover Leaking Walls And/Or Mould/Mildew?March 2024
As far as the insurance industry is concerned, a leaking wall and/or mould mildew are defects and are not covered by most of the building and PI insurance policies.
Your Engineer can eliminate the need for horizontal bars with DincelMarch 2024
When using Dincel, your engineer can eliminate the need for horizontal reo bars.
Does Your Building Comply With Mould/Mildew Requirements of NCC-2022 & NSW Water Management Act?January 2024
The health of building occupants can be affected if the internal surface of an external (façade and basement) wall demonstrates mould/mildew and fungus development. There are two conditions for these problems to emerge: (a) the presence of water vapour and (b) the availability of nutrients.
Beyond British Standard BS8102:2022December 2023
In the absence of an Australian Basement Code, building professionals defer to using the well-known British Basement Construction Code – BS8102:2022. Whilst a useful starting point, this code is inadequate in Australia as it does not take into account:
Celebrating a Dincel milestoneDecember 2023
Recently, we celebrated the official launch of our Dincel Structural Walling Waterproof System, following many years of research and development. A sincere thank you to all those who joined us for these celebrations. We look forward seeing many projects utilising this system in the coming months and well into the future, while celebrating more milestones for Dincel along the way.
A Q&A With Steve Darwell, Chief Operating Officer at Dincel Structural Walling.August 2023
A veteran within the industry, Steve recently sat down with us to discuss the Permanent Formwork Industry Council (PFIC), and how Dincel Structural Walling remains committed to solving the industry's permanent polymer formwork needs.
Fire Compliance - Report by Grove & Wynn-JonesAugust 2023
There is significant misunderstanding in the industry about the application of CodeMark Certificates, particularly as they relate to the assessment of a product’s suitability in relationship to fire.
Spotlight on the Dincel Waterproof Basement SolutionAugust 2023
GUIDELINES FOR AN AUSTRALIAN BASEMENT CONSTRUCTION CODE - BEYOND BRITISH STANDARD BS8102 - 2022
A CULTURE OF INNOVATIONJuly 2023
Innovation starts with identifying the need – the problems, difficulties and possible improvements. The Dincel company culture is based on wanting to bring the best out of each individual
THE ULTIMATE SOLUTION FOR BASEMENTS Ground Breaking InnovationJuly 2023
Following an extensive third-party peer-review process, Dincel is pleased to share the findings of an independent report into the efficacy of its new waterproofing solution for basement walls using Dincel’s patented panels and accessories.
Investing In Training To Improve Building OutcomesJuly 2023
With workmanship on construction sites coming under more and more scrutiny, putting an emphasis on training has become increasingly necessary.
The rise and rise of Dincel Structural WallingJuly 2023
In an Australian first, Dincel is offering a void free warranty when you choose to pour your Dincel Structural Walling with Self-Compacting Concrete and the installation is to Dincel’s specifications.
