Science meets history
Concrete, as you know, is one of the most prolifically used construction materials on the planet.
We could say a few words about its longevity (and how that counters its alleged carbon footprint). Or we could talk about its strength and versatility. Then again, there’s its sheer cost-effectiveness. Overall, concrete offers many benefits as a building material, hence its significance.
Not that there’s much about concrete which hasn’t already been said, of course. What other construction material has had so much study and research, or been the topic of so many white papers?
So it’s possible we can’t tell you anything new about concrete … maybe.
Ever heard of concrete hydrogels?
Of course, you have, you’re a dedicated Markham newsletter reader. But you’ll admit we’re one of the few teams talking about the topic. There are not many others on the planet focusing on this intriguing technology. More about that later.
Let’s step back a little. One of the key components of concrete, which develops as it cures, is C-S-H (Calcium Silicate Hydrate). This combination occurs in various molecular forms and acts as a binder within the matrix of the mix.
The atomic structure of C-S-H is similar to that of Tobermorite, a rare mineral that occurs in nature and is also found in ancient Roman concrete. And here we touch on history.
A brief look at Roman concrete
The Romans developed an early concrete and used it extensively – many examples of which still survive 2000 years later. They favoured the use of pozzolanic volcano dust in their mix, which had a high content of alumina and silica. This produced a tough concrete which was highly resistant to seawater. (Some forms would even set underwater.)
Concrete technology was largely lost after the fall of the Roman Empire until its re-discovery about 1000 years later.
Development was slow even then, but with the Industrial Age, concrete technology once again became the subject of investigation, and modern ‘Portland’ cement was established as a prime ingredient around 1840. Not that it had all the benefits of the ancient Roman mix design…
 |
And Hydrogels?
The Industrial Age was an era of heightened study and curiosity across all fields, including the composition of materials to understand how things worked, whether for scientific and/or commercial purposes. The first mention of ‘hydrogels’ appears in a German paper on the metal copper in 1896. Over time, they have become commonly used in a range of medical and body care applications, such as wound dressings, contact lenses, baby nappies, and even drug delivery. Hydrogels also appear in agriculture for water retention and agrochemical release.
Around the 1940’s, it was discovered that hydrogel formation in concrete could be induced by the introduction of nanosilica particles. This forms a C-S-H-type molecule, utilising uncured lime and free moisture already within the slab, and at the same time immobilising them in a gel. A hydrogel.
The technology was successfully trialled for waterproofing a London subway tunnel in the 1950s.
The two technologies – concrete and hydrogels – had met.
 |
Commercial development
Identifying the concept of the induced hydrogel was significant. The next challenge was to make the technology commercially reliable, predictable, and viable. This was achieved in the early 1980’s, in USA. A number of notable examples of the early use of concrete hydrogels included
- Protecting concrete seating in a major stadium from soft drink attack.
- Protecting concrete driveways and parking garages in snow zones from freeze-thaw cracking.
- Waterproofing free-formed concrete swimming pools.
It became evident that the benefits of high-quality concrete hydrogel treatments are permanent, enhancing the life of the concrete and never needing re-application.
New direction
In 1996, the team at MARKHAM were approached by the supplier in the USA, and a new direction was developed. MARKHAM achieved early success in waterproofing a university basement in Christchurch, which is in (dry) use to this day. They then worked with the supplier to develop the product in various directions for multiple applications…
- A sealer and anti-dusting hardener for warehouse and car park floor slabs.
- As a moisture-control system, preventing adhesion and bubbling beneath commercial floor coverings.
- A chloride-protection variant for marine and civil infrastructure remediation.
- A hygiene sealer for floor slabs in aged care and healthcare institutions.
An amazing array of benefits
Extensive testing in MARKHAM’s own laboratories and by various independent entities has shown that the simple technology of immobilising moisture offers an amazing array of benefits.
- Enhanced curing – because the moisture differential through the slab is minimised.
- Moisture control under floor coverings – because the moisture cannot freely rise as vapour out of the slab.
- Waterproofing – the concrete’s porosity is sealed to prevent water entry or movement.
- Hardening and dust control. MARKHAM hydrogel treatment penetrates to 150mm, avoiding the risk of delamination, which is so common with shallow concrete hardeners.
- Protection from contamination. Moisture-borne contaminants, the key cause of concrete deterioration, cannot enter the slab, move about, or react freely. Importantly, this protects against chloride and sulphide attack and against the internal development of ASR and DEF.
Up to date
If you’re involved with concrete in the construction industry or the maintenance of concrete infrastructure, there’s a fair chance we can help make your job easier in some way.
Improve concrete quality? Save money? Speed up processes? Enhance service life? Reduce repair bills?
Talk to us. Collectively, our team has seen more than its fair share of real sites and projects, and we know what works where. Get in touch today!
STOP PRESS!
Ask us about sustainably-sourced waterproofing admixtures!
More learnings with our on-demand webinar “Strength vs Durability“.
