Concrete: the substance we rely on, but hardly notice

From highways and bridges to water infrastructure and buildings, concrete underpins modern life - but most of us only notice it when something goes wrong. We spoke with Dorian Borosnyoi-Crawley, a Senior Concrete Technologist in WSP’s Research team about WSP’s concrete expertise, how concrete gets tested, and what it takes to make structures last.

First, tell us about your role - and the concrete specialist capability at WSP Research.

WSP Research brings together a genuinely multidisciplinary group - engineers, chemists, physicists and materials scientists - combining laboratory services with specialist consultancy to improve how infrastructure is designed and performs over time.

WSP Research does more than 'standard' concrete testing. What does that look like in practice?

Dorian: The strength of a specialist team is being able to connect the lab results to what’s happening in the real world - whether that’s designing new concrete, verifying compliance, or diagnosing why an existing structure is deteriorating.

A big part of our work is concrete durability and performance assessment: sampling, core testing, and evaluating concrete in existing and new structures, alongside lab testing that helps predict future performance.

You’ve got a strong international research and standards background. How does that shape what you bring to New Zealand?

Dorian: Concrete is local - aggregates, exposure conditions, construction practices - but the fundamentals and the evidence base are global. I’ve been involved with international technical groups focused on reinforced concrete serviceability and reinforcement topics, as well as committees working on in-situ strength assessment approaches.

I’m also active in standards and professional communities. That connection to international thinking helps translate research into practical guidance and helps keep our local practice aligned with the best knowledge.

Why is concrete so fundamental to modern civilisation?

Dorian: Quite simply, there is no civilisation without concrete. It’s everywhere - water infrastructure, energy systems, roads, bridges, tunnels, buildings. You can’t find anything cheaper that delivers the same performance per cubic metre per dollar.

And when it’s designed and made properly, concrete can last a very long time. Concrete quietly underpins the economy, yet most people never think about it.

What exactly is concrete made of?

Dorian: The largest component is aggregate - gravel, sand and crushed rock - which makes up most of the volume. But not all rock is suitable; only certain types have the right properties.

The binding agent is cement. To make cement, limestone and clay are heated to around 1,400°C - energy-intensive, and it releases carbon dioxide. That’s why cement is often described as carbon‑intensive.

When cement mixes with water, it becomes highly alkaline. That alkalinity is what helps protect steel reinforcement inside concrete from corrosion.

Why do we need steel in concrete?

Dorian: Concrete is excellent in compression but shy in tension - it will crack where tension occurs. Steel reinforcement - rebar - takes those tensile forces.

But steel naturally wants to return to iron oxide - rust. Concrete’s alkalinity keeps reinforcing steel stable. If concrete becomes too permeable, carbon dioxide or chlorides can enter, reduce that alkalinity, and corrosion can begin.

What causes concrete to crack?

Dorian: People often assume cracks mean structural failure, but cracking can come from many things - loads, shrinkage as water evaporates, poor compaction, incorrect mix proportions.

Concrete will harden no matter how you mix it, which makes everyone think they’re an expert. Whether it’s 'good' concrete is another matter.

What does WSP test - and what are clients usually trying to answer?

Dorian: In broad terms, clients want confidence: Is this concrete fit for purpose today - and will it still be fit for purpose decades from now?

WSP’s materials testing and analysis capability covers a wide range of concrete testing - including fresh concrete sampling and testing, mix trials, core sampling and evaluation, and standard strength testing (compressive, tensile and flexural).

We also test key performance properties such as modulus of elasticity, creep and shrinkage, plus durability indicators including carbonation depth and resistance, chloride contamination/diffusion, chemical resistance, and water permeability and absorption - alongside corrosion risk assessments.

Importantly, that testing is carried out in accordance with New Zealand, Australian and other international standards, so results are comparable and decision‑ready.

How is the industry addressing sustainability concerns?

Dorian: Cement is inherently carbon‑heavy, but we can reduce how much we use. Supplementary cementitious materials - SCMs - have been used for a long time. Slag and fly ash are classic examples, and there are newer options too.

But the most practical sustainability lever is durability: high‑performance, low‑permeability concrete lasts longer. Build it once. Build it right.

Can concrete be recycled?

Dorian: Yes. Both the steel and the concrete can be recycled. The practical challenge is access and economics. Once it’s mixed through rubble, it can be cheaper to produce new material than recover and process the old.

Where high‑performance concrete isn’t required, recycled concrete can be a cost‑effective and sustainable option.

What sets WSP Research’s concrete capability apart?

Dorian: The combination of accredited testing and specialist interpretation is crucial. WSP Research provides laboratory services and specialist consultancy to improve the design and performance of infrastructure, supported by accredited management and lab practices (including ISO 9001, and many laboratory services with ISO 17025 accreditation).