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Waterproof Concrete
Ideal for Basement work, underground structures, tunnels, car parks, water tanks, reservoirs, dams, swimming pools, retaining walls and anywhere that is flood prone.
Any project that involves keeping water in or out, waterproof concrete is the
“essential” product to use!
Mixamate offer waterproof concrete deliveries in and around
the South East and Yorkshire.
Our waterproof concrete is sourced from leading industry brands like Chryso and Sika.
Contact our team today for a free quotation
Understanding Waterproof Concrete
Waterproof concrete consists of a specially formulated mix combining standard aggregates, cement, water and additives.
This blend includes additional sand to fill all voids between the stones and extra cement to fill the gaps between the sand particles. Importantly, waterproof concrete contains significantly less water, ensuring that the cement grains remain closely packed together.
Typically, standard concrete has more water, which separates the cement grains, reducing friction and enhancing workability. While labourers often prefer the ease of working with wetter mixes, this excess water weakens the concrete, leads to drying shrinkage cracking, and increases porosity—issues that clients generally want to avoid.
As the surface of each cement grain interacts with water, a gel forms that expands slightly.
This gel eventually crystallizes into long, thin structures.
The closer the cement grains are to one another; the more interlocking occurs among the crystals from adjacent grains. This interconnected network of crystals throughout the concrete is what ultimately provides strength.
With less water, this network becomes denser, resulting in stronger, more water-resistant concrete.
The key distinction between waterproof concrete and standard mixes lies in the formation of a continuous sheet of interlocked crystals that envelop every cement grain shortly after the concrete begins to set.
In contrast, a wetter mix leads to cement grains surrounded by interlocking crystals that may remain disconnected from those of neighbouring grains for a prolonged period, depending on the
excess water.
Until the crystals interlock completely throughout the concrete, it cannot be considered fully set. Excess water can lead to a thinner mat of crystals and can create pathways for water to penetrate under pressure.
In waterproof concrete, the mat of interlocked crystals thickens, trapping remnants of cement grains on one side and sealing water in tiny pockets on the other. Once water can no longer reach the cement grains, the curing process halts, rendering the concrete waterproof.
However, this waterproofing is susceptible to cracking.
As concrete cures, it expands with heat and contracts as it cools, typically within a day or two. Cracking is inevitable in concrete structures that are restrained at their ends. For instance, a 20-meter-long basement retaining wall made of waterproof concrete may shrink by approximately 4mm.
The solution is to incorporate sufficient horizontal steel reinforcing bars that grip the concrete on either side of a crack, limiting its expansion to no more than 0.2mm. This approach may lead to multiple cracks that cumulatively equal the total thermal shrinkage—20 cracks at 0.2mm each for a 4mm shrinkage over 20 meters.
When waterproof concrete cracks, it is the continuous mat of interlocked crystals that fails. Unused water may find remnants of cement grains, triggering the curing process anew. Cracks up to 0.2mm wide can completely heal through a process known as autogenous healing.
In contrast, some concrete elements such as basement floor slabs can expand and contract as a whole without cracking.
Non-waterproof concrete will always be weaker and more porous than waterproof concrete due to its less optimal blend of solids and the greater separation caused by excess water. While additional water increases the total amount of cement converted into crystals, it simultaneously diminishes the interlocking of those crystals around each cement grain with those surrounding neighbouring grains.
Mixamate work very closely with many companies
that offer waterproof concrete.
We are particularly proudly to work with – Basement expert – www.basementexpert.co.uk
This company are specialists in their field and top of their league when it comes to waterproof basements. It is a real pleasure working with these professional guys.
Philip, the company director, was kind enough to write a testimonial for us on this opinion and overall experience with Mixamate. See below!
First, because they weigh batch exactly the quality and consistency I require. At site. I have a full 2 hours of working time. Nowadays, drum trucks get caught in traffic. That delay is my working time. Too often, their concrete sets soon after it arrives, affecting my finish.
Second because they produce concrete relatively slowly. Up to 9 cubic metres an hour. This allows me to use a very small team most of the day, instead of a team twice the size who finish at midday and expect a full day’s pay.
I always use a pump truck. The 3” delivery hose is easy for one person to lift and pull around, even full of concrete.
Mixamate saves me a lot of grief and money as well.
Special thanks to Philip Sacre for his great comments and continued business!
