Tech Talk

Why Concrete Must Be Cured at the Time of Pour

Overview

Concrete is the backbone of modern infrastructure. From house slabs and driveways to bridges, warehouses, tunnels, and airport aprons—every structure relies on concrete for its load-bearing strength and longevity. But while much attention is paid to the mix design and placement techniques, there’s one vital step that often gets neglected: curing.

Across Australia, we’ve seen that many concreters, builders, supervisors, and even engineers continue to underestimate the value of curing immediately at the time of pour. Yet curing is the single most important step in ensuring concrete achieves its full design strength, durability, and service life.

This document outlines why curing matters, what happens when it’s skipped or delayed, and how early curing prevents avoidable structural issues, saving time, cost, and long-term liability for builders and asset owners alike.


Why Is Curing Essential?

Curing is the process of maintaining the right moisture and temperature conditions in newly placed concrete so the cement can fully hydrate. Hydration is the chemical reaction between water and cement particles that forms the hardened cement paste—this paste binds the aggregates together and gives concrete its strength.

If curing is delayed or skipped:

  • Excess moisture evaporates too quickly—especially in hot or windy weather.

  • Cement particles don’t fully hydrate, resulting in incomplete strength gain.

  • Plastic shrinkage cracks, surface dusting, and long-term durability issues develop.

  • The final structure may suffer early failure, leaks, or surface degradation.

Concrete needs to retain enough internal moisture for at least 7 days—and ideally up to 28 days—for optimal hydration. Curing compounds that penetrate and seal the surface help lock in moisture from day one, providing a high-performance cure without disruption to the job site.


Performance Benefits of Proper Curing

Research and field studies consistently show significant improvements when concrete is properly cured:

🔹 Strength

  • Properly cured concrete achieves up to 60% higher compressive strength compared to concrete left to dry out prematurely.

  • Long-term strength continues to develop beyond the initial 28 days when hydration is protected.

🔹 Crack Reduction

  • Curing reduces shrinkage-related cracking by keeping the surface moist during early-age drying.

  • This prevents unsightly surface cracks that compromise aesthetics and lead to long-term structural issues.

🔹 Abrasion & Impact Resistance

  • Cured concrete forms a denser surface layer, better resisting foot traffic, vehicles, and equipment wear—critical in high-load environments like warehouses, driveways, and mine sites.

🔹 Watertightness

  • Proper curing dramatically improves surface densification and internal matrix structure, reducing permeability.

  • This is key for basement slabs, wet areas, water tanks, and anywhere moisture ingress can lead to mould, corrosion, or efflorescence.

🔹 Freeze-Thaw Resistance

  • In colder regions, curing improves concrete’s ability to withstand repeated freeze-thaw cycles without spalling or cracking.


Real-World Consequences of Skipping Curing

Across Australia, builders are under pressure to deliver quickly—especially in summer. But rushing the process or skipping curing can create long-term problems that cost far more to fix than the small investment in doing it right the first time.

Some common issues that arise when concrete is left uncured:

  • Weak surfaces that dust, delaminate, or flake

  • Uncontrolled cracking and slab curling

  • High porosity leading to water ingress and rusting of reinforcement

  • Reduced life expectancy and maintenance-heavy assets

For commercial projects, infrastructure, and residential slabs alike, curing is not an optional luxury—it’s a technical necessity.


Temperature Matters — The Hotter It Is, The Faster It Fails

In Australia, ambient temperatures on a summer slab can easily reach 35–45°C. These high temperatures accelerate surface moisture loss before the concrete has even set.

Independent tests show that:

  • Concrete cured at 23°C develops a typical compressive strength curve over 28 days.

  • Concrete cured at 38°C without protection may lose over 30% of potential strength due to rapid water loss.

That’s a big risk to take for a simple oversight.

Modern curing compounds, such as penetrating water-based sealers, allow crews to cure as they go—ensuring hydration begins immediately without the need to return to strip and rewet hessian or apply plastic sheeting.


Curing Compounds: The Smart Solution

Integra’s range of curing technologies includes solutions that go beyond surface-level benefits. Our DEEPCURE and HARDROX treatments don’t just meet AS3799 requirements for curing—they also deliver long-term waterproofing, surface hardness, and chemical resistance.

Applied immediately after finishing, these compounds:

  • Create a breathable yet sealed surface that locks in moisture

  • Improve finish durability for high-traffic zones

  • Comply with Australian Standards for curing performance

The result? A single-step application that saves labour, protects from day one, and delivers a denser, longer-lasting concrete surface.


Conclusion: Cure It or Compromise It

Concrete is not waterproof by default. It’s not immune to heat, drying winds, or site neglect. But it can be protected—if it’s cured correctly and immediately.

For the builder: curing avoids rework and call-backs.
For the engineer: curing means strength and compliance.
For the asset owner: curing delivers a durable structure that lasts.

In short: cure it or compromise it.


References


Author: Lance Reynolds
Date: April 2025
Contact: sales@integraindustries.com.au | 1800 500 803