How-to: Construction, Concrete & C02 in 2023, Explained
TL/DR? At the bottom…
The Current State of Stats
Since the turn of the last century, the consensus that environmental damage was a necessary evil of industrialisation has given way to people seeking solutions to the construction pollution problem.
As established economies look towards construction as a recession hedge and emerging ones as a means of rapid urbanisation, the demand for all construction materials continues to rise exponentially. Concrete and its main ingredient, cement, are at the forefront.
With 68% of the world population projected to live in urban areas by 2050, concrete is a prime example (if not unique) of runaway costs changing how an industry needs to think, even if environmental concerns do not.
In April 2023, Laing O’Rourke publicly announced their proposed roadmap transitioning from Ordinary Portland Cement (OPC) towards several lower-carbon alternatives, including the industrial by-products granulated blast-furnace slag and pulverised fuel ash.
But what are some of the other alternatives your business could consider?
Could some of them even save everyone money?
What is this all about, then?
Concrete is the world’s most popular material, second only to water (another vital concrete ingredient). Why? Because of its widespread applications and materials being easy and cost-efficient to source, mix & use.
To keep up with humanity’s rampant concrete consumption, global cement production is projected to increase to over five billion tonnes a year over the next thirty years, intensifying cement manufacturing. Current production processes, fuel requirements and product end-use are already responsible for 8% of global CO2 emissions.
So why might using an alternative be beneficial to your current project?
Do you know how much you could reduce your project’s carbon footprint?
Introducing the “Crete” Family — Alternatives to Concrete
Hempcrete
Also known as hemp-lime or hemp-aggregate composite (HAC) is a mixture of hemp hurds, lime and water and is most commonly used for medium-scale building projects.
Hemp, like all crops, captures CO2 as it grows. But, unlike most building supplies, it is a carbon-storing material, absorbing carbon dioxide throughout its lifecycle. Hempcrete also reduces CO2 consumption during manufacturing — requiring three times less heat than concrete — and doesn’t utilise petrochemicals.
In terms of installation, hempcrete doesn’t require specialist tools, equipment or skills. It has no associated health risks at any stage of its lifecycle, especially when compared to insulation foam, fibreglass, cellulose or chemical treatment. Once in place, it is low maintenance, water repellent, fire & pest resistant and earthquake-tested.
“If someone comes to us and says they want to build a really energy-efficient eco house which is going to last 100 years, then we would say use hempcrete.” — Tom Woolley, Queens University, Belfast
Hempcrete is also an environmentally friendly alternative due to its lower thermal conductivity than almost all current materials. It is a highly effective insulator with a typically longer lifecycle than industry-standard insulation. Where heating or cooling systems aren’t necessary, hempcrete can dramatically reduce build and maintenance costs.
With a comparable compressive strength and lifespan, hempcrete could replace concrete in many applications.
Grasscrete
Also known as Void Structured Concrete, Grasscrete is an eco-friendly alternative mainly because it uses fewer resources and instead relies on nature (i.e. grass) to provide additional structural support.
Although incapable of replacing many concrete applications, Grasscrete can hide in plain sight if desirable (e.g. supporting banks or gardens), simultaneously providing excellent stability, drainage and support. For drainage applications, it can be installed at a slope of 1:2, thereby providing enhanced management for waterways and spillway systems.
Grasscrete is highly hydraulically efficient from installation and improves over time as long-stemmed grass growing through the Grasscrete flattens into a protective thatch under heavy flow. Traditional concrete systems require bespoke-engineered panels (that degrade over time) to compensate for hydrodynamic erosion.
By simulating a water system, Grasscrete decreases the hydraulic roughness and drastically increases product lifespan. Grasscrete would offer an enhanced Return-on-Investment (RoI) for publicly-funded or government agencies where low initial cost and maintenance matter.
But it is also applicable to urban scenarios. Using less concrete and no rebar means a less intensive process and a reduction in any associated carbon emissions of up to eighty per cent (compared to traditional concrete). Despite using less concrete, Grasscrete remains load-bearing up to forty tonnes, making it suitable for heavy maintenance, emergency service and plant vehicles.
From an environmental perspective, Grasscrete can use any concrete-type material (e.g. ashcrete, concrete, hempcrete). The grass component captures CO2 for the entire project lifecycle (and beyond) and makes it carbon-negative.
Other uses include gardens, walkways, paths, vehicle parking, rooftops, hard standings, medians, verges, banks and spillways.
Greencrete
Silica-based (i.e. recycled glass) solution, greencrete, is lighter than regular concrete but with equivalent relative strength. Less heavy products are easier to manufacture (and transport) more locally.
Using only recycled elements makes it an eco-friendly alternative with a better CO2 rating than concrete. Using recycled materials also promotes the concept of Closed Loop Material Construction (CLMC).
Glass is easy to collect and recycle for construction purposes. Greencrete could be applied successfully to develop remote areas like South East Asia or developing countries where urbanisation demand outstrips material supply.
In locations lacking adequate sanitation or recycling infrastructure — for example, Sub-Saharan Africa — it also encourages positive industrial growth and self-reliance.
Greencrete has the same lifespan as regular concrete and is widely applicable to current concrete uses. Weighing less makes it especially good for jobs where weight or structural integrity are factors (like roofing or cladding applications). It functions equally well as a base for roads and parking lots.
Timbercrete
Timbercrete is a mixture of wood waste — typically chips, sawdust and OPC. Although less eco-friendly than other options, virtually every construction project creates wood waste. Near-infinite supply aside, Timbercrete has several strong points.
Recycling building waste reduces energy-intensive processes but also increases awareness of concepts like CLMC, 3D printing, modular building, and offsite construction to help change perceptions and behaviours.
From an environmental perspective, the material sequesters carbon (like hemp), safely absorbs vehicle emissions and has excellent thermal mass properties.
Using virtually any wood-related waste material means constituent elements can be locally sourced, reducing associated costs and decreasing reliance on imported materials.
In usage terms, Timbercrete is a viable alternative to traditional concrete, increasingly used for formwork and to produce bricks, blocks, panels & pavers. Timbercrete is engaged in residential, industrial and commercial building projects, highways, landscaping, acoustic dampening, fire-proofing and external cladding.
It is 2.5 times lighter than concrete or clay, meaning units of Timbercrete can be made larger. Smaller units are easier to work with, and forming big bricks improve efficiency and build time by reducing the number of necessary processes. Furthermore, Timbercrete is flexible and fabricated into various sizes, colours, shapes and textures.
It’s even bulletproof (no, really).
HONOURABLE MENTIONS
Ferrock
A happy accident, Ferrock is made using steel dust and ground glass to create a carbon-neutral product similar to concrete. Made from 95% recycled materials, it is chemically inactive, stronger, and more flexible than concrete.
Shellcrete
Currently in late-stage development but already licensed for use in Europe by Belgium inventor, Localworkstudio. Shellcrete uses waste seashells as aggregate, with initial concrete and clay use case comparisons extremely promising.
StarCrete
Developed by researchers at Manchester University for extraterrestrial construction, Starcrete combines astronaut tears, potato starch and lunar dust to create a material almost three times harder than concrete.
Wrapping Up
Technology is making it increasingly difficult to ignore the effects of industry on the environment and shining an auditing light on unprincipled solutions employed by the most prolific abusers.
This combination of factors and timings has spurred industry leaders to begrudgingly jump before being pushed into researching more environmentally friendly options, including the ConcreteZero initiative (members include: Laing O’Rourke, Landsec, Moda Living, Buro Happold, Grosvenor, Willmott Dixon and WSP).
But in an industry where ALL the big fish get hooked regularly for collusion, corruption, bid rigging and price fixing — any meaningful change will have to be driven by constitutional and legal force.
From theoretical planning like Digital Twins and closed-loop systems to alternative materials & fuels — the race to hold construction responsible is on.
Concrete seems like a great place to start.
Tom@TG
TL/DR
- Concrete is great for civilisation but terrible for the planet.
- Recent law and policy changes, including zero-emission pledges like tightened fuel emissions, finally brought the climate crisis to the construction coalface.
- Global instability and domestic demand heavily (or entirely) reliant on imported materials continue to strain supply, with national demand driving global price inflation.
- There are viable alternatives, but they aren’t being used for a range of reasons.
- The Construction industry, obstructed by top-down resistance to technological, environmental and labour-related reforms, is falling behind on all Key Performance Indicators (KPIs) and virtually all other sectors.
- Hampering research into alternative methods, fuels & materials also stifles any potential local industry and any associated devolution of power.
What do you call a platform that promotes a construction industry working for the good of everyone? TradeGraft.
