The ABCs of Precast

Precast concrete glossary

A quick dictionary of all things precast

Don’t know your king posts from your aggregate? Lost in acronyms like UHPC and GGBS? Don’t worry, we’re here to help.

Construction jargon is hard to understand at the best of times. If you’re new to it, the terminology can be downright intimidating. That’s why we’ve put together this A-Z of common precast-industry terms.

So, if you come across a word you’re unsure about, scroll down our quick ABC and see if it’s there. If it’s not – please don’t hesitate to ask! We’re always happy to help, and definitely won’t judge you for not knowing what something means (after all, knowing that stuff is our job!


The A-Z of precast terms


A – Aggregate

A coarse, rubble-like mix of various particulate materials. Common aggregate mixes can include anything from sand to recycled fragments of concrete. Aggregate is used to make strong, durable concrete and mortar.


B – Biomimicry

A technique which uses natural patterns and structures in human construction. For example, early jet planes used biomimicry to achieve their streamlined shape and unique wing design – copying from birds and fish. We use biomimicry to provide valuable habitat on, within, and around our precast units.


C – Cement

Cement is a binder – a material that helps stick other materials together. It’s used a lot in traditional concrete to bind aggregate. Cement has a high carbon footprint so, if you’d prefer a low-carbon, low-cement alternative, check out our eco-friendly Sensicrete range.


D – Digital Construction (BIM)

The use of digital technology to design, model, and manage construction projects. BIM (Building Information Modeling/Management) involves complex 3D digital design, and the use of digital data to manage construction projects.


E – Eco Engineering

Techniques which integrate human and natural needs in a way that benefits both. For example, we use bio-blocks to make structures that are useful and beautiful for humans, and which also provide a space for plant and insect life to grow and flourish. They are also fantastic at capturing carbon. Similarly, we use biomimicry techniques to create marine defences that mimic natural structures. These structures both protect human communities and provide vital habitat for endangered marine species.


F – Fire-resistance

The ability of a material to withstand fire (and for how long). Our concrete fire and blast walls can resist and hold-back fire for up to four hours, context and product  depending. The highest classification for building products in the Eurocodes is A1, meaning a material is non-combustible. Concrete and its components are included in this classification because its mineral contents – aggregate, cement and water are non-combustible. For concrete containing steel reinforcement there are other design criteria that need to be considered to meet the required standards.


G – Ground Granulated Blast-furnace Slag (GGBS)

A long name for a complicated process. To make GGBS, molten iron-slag (a by-product of iron from the steel-making process) is removed from blast-furnaces and plunged into water or steam. This turns it into a very brittle solid, which is then crushed up into a powder rich in calcium silicate hydrates. GGBS adds a lot of strength and durability to a concrete mix.


H – Health & Safety

Often mocked, but very important! Health & Safety is all about preserving the lives and health of everyone involved in a project. From wearing hard hats to creating safe structures, the health & safety of our employees, clients, and the ultimate end users of our projects is something we take very seriously.


I – Installation

The process of getting your precast off the factory floor and into your site. We can deliver and install most products . What’s more, because our precasts come…well…precast, the process of delivering and installing them is a lot faster, cheaper, and less labour-intensive than pouring them from scratch on-site.


J – Joint sealing

The process of sealing the gaps where two or more elements join. Modular construction often involves interlocking different elements (or ‘blocks’, if you prefer) together. To make sure that the resulting structure is totally solid, we seal joints with strong, impermeable mastic.


K – King Post

An upright post which supports a structure. We use them in retaining walls, where they hold up and support the prestressed wall panels.


L – Lifting Shackles

Lifting shackles connect slings, rigging, chain, or whatever else you’re using to lift with the either want to lift, or the thing lifting it. OK, that wasn’t a very clear explanation! Here’s an example: If you are lifting a precast with a crane, the lifting shackles are the metal bits which connect the crane chains to the precast units.


M – Moulds

If you ever made jelly with your gran, or played with papier mache at pre-school, you’ll know what a mould is! A hollow container which helps to shape setting-materials like plaster into certain shapes. We use industrial-scale steel moulds to manufacture our precast products. By making our units this way, we ensure consistent, factory-controlled quality of a kind that you just can’t get by pouring concrete on-site.


N – Nature-based solutions

Natural solutions to human problems. We like to work with nature rather than against it. And nature has some of the most radical and effective solutions around. For example, our revolutionary Sensicrete uses natural limestone-producing microbes to reseal cracks in concrete as they appear. This nature-based solution is helping us to provide structures that heal themselves – making them safer, more durable, and a lot less expensive to maintain!


O – Offsite manufacturing

Manufacturing that takes place away from the construction site. We create our precast offsite, in our own factory. The advantage of this is that we can produce consistently high quality products in factory-controlled conditions. This kind of quality control is rarely (if ever) possible on even the best-managed site.


P – Productivity

The rate at which something is achieved. In a project context, ‘productivity’ is the rate and effectiveness with which tasks are completed. A very productive worker will get a lot done – and do it to a high standard! By choosing our precasts, you can get more done with less time and effort. This will boost the productivity of your project by a long margin.


Q – Quality

A thing’s ‘quality’ refers to how high its standard is compared to other, similar things. For example, our precasts are high quality because they out-perform other precasts in terms of durability, effectiveness, appearance, and more.


R – Reinforcement

In a concrete context, ‘reinforcement’ refers to material used to strengthen structures and/or to hold them in place. For example, steel rebar and mesh is commonly used to reinforce concrete. Concrete works great when it’s compressed, but rubbish when it’s put under tension. Steel is the exact opposite, so makes the perfect addition to strengthen concrete structures.


S – Sensicrete

A new range of eco-products including a revolutionary self-healing variety of concrete. We’re currently the only company in the UK to offer bio-concrete! As well as having less embedded carbon, Sensicrete can self-seal cracks the moment they appear, thanks to limestone-producing microbes within the mix. When exposed to oxygen and water (as happens when a crack forms), these dormant microbes ‘wake up’, and begin to busily seal themselves back into the mix by producing strong limestone. This self-healing process massively extends the lifespan of the structure with very little human effort!


T – Testing (cube/compression)

To test the strength of our concrete, we use something called a Cube Test. This involves taking a sample  of concrete and measuring how much pressure it takes to crush it. The higher the number, the stronger the concrete.


U – Ultra-High-Performance Concrete

UHPC is an exceptional type of concrete developed for high-stress environments. It’s extremely durable, and capable of withstanding a lot of pressure. It’s often used in structures that need to hold strong against challenging conditions – like busy bridges, and dams.


V – Value engineering

Value engineering involves looking at every aspect of a project, and seeing if the objectives can be achieved at a lower cost. For example, with some value engineering you may discover that using precast will give you the same (or better) results as in-situ concrete, but without the added labour and time costs.


W – Water

Water is a precious resource. Traditional concrete construction uses (and wastes) a lot of water. We aim to reverse that trend. We have reduced the overall amount of water we use, and recycle the water we do. We also source our water ethically when we can through initiatives like rainwater harvesting. 


X – Exposure Classes

Yes, this technically starts with an E – we know! As we get to the end of the alphabet we admit we’re reaching a bit…but all the words we’ve included are very important, so bear with us! Exposure classes refer to the conditions concrete may be subjected to. For example, class XF refers to the potential for corrosion caused by freezing and thawing. Concrete that will be placed in XF conditions must be able to withstand freezing and thawing.

There are five broad exposure classes:

  • XC: Corrosion by carbonation
  • XD: Corrosion by chlorides
  • XS: Corrosion by marine chlorides
  • XF: Corrosion by freeze/thaw
  • AC: Corrosion by chemical attack


Y – 100 Year Design Life

The ‘design life’ of any structure is the amount of time the designer intends for it to be used. We always aim for durability and longevity, so many of our precast products have a 100 year design life. With the high quality of our products, that lifespan is also guaranteed to have low maintenance costs (even lower if you choose our Sensicrete self-healing mix!)


Z – Net Zero Carbon

Net Zero Carbon refers to the UK government’s ambition to achieve a balance between the amount of carbon put into and taken out of the atmosphere by 2050. We are working hard on our part in this. For example,  our modular precast system lowers the carbon footprint of any construction site by speeding up the whole building process, reducing the amount of traffic coming in and out on a regular basis, and using a lot less concrete and steel than in-situ pours. On top of this, we have a tree planting programme to neutralize our carbon footprint. Already, trees planted by us are consuming CO2 all over the world. And we’re constantly setting and tightening green goals for our factories.