Concrete is one of the most widely used building materials across the Kingdom of Saudi Arabia (KSA). From major infrastructure projects in Riyadh and NEOM’s ambitious developments to residential pavements in Jeddah and Dammam, concrete must perform reliably in harsh climates and heavy use environments. However, cracking is one of the most common performance issues in concrete — and preventing it requires intentional planning and execution.
In this blog, we’ll explore why cracks happen, the role of concrete curing and expansion joints, and best practices tailored for Saudi Arabia’s climate and construction context. This is a must‑read for engineers, contractors, architects, and project managers committed to long‑lasting concrete structures.
Understanding Concrete Cracking: Causes and Consequences
Concrete cracks for many reasons, but most cracks fall into these categories:
Plastic Shrinkage Cracks
These occur soon after placement, while concrete is still plastic. Rapid moisture loss — common in hot, dry climates like KSA — accelerates evaporation and leads to shrinkage cracking.
Drying Shrinkage Cracks
Once concrete hardens, it still loses moisture as it dries. If this shrinkage is restrained, tensile stresses build up, causing cracks.
Thermal Cracks
Concrete expands and contracts with temperature changes. The Kingdom’s extreme day‑to‑night temperature swings can create stress that results in cracking.
Load‑Related Cracks
Overloads, heavy traffic, or stresses from structural movements can contribute to cracking if the concrete design or reinforcement isn’t adequate.
The Role of Curing in Preventing Cracks
Proper curing is one of the most effective ways to minimize cracking. Curing maintains adequate moisture and temperature conditions that allow concrete to gain strength and reduce shrinkage.
Why Curing Matters
When concrete loses moisture too quickly:
- Hydration stops prematurely.
- Strength development is reduced.
- Shrinkage increases.
- The likelihood of cracking escalates.
In the harsh climate of Saudi Arabia — especially during summer — moisture loss can be rapid. This makes curing not just important, but critical.
Best Curing Practices for the Kingdom’s Climate
Here are proven practices that deliver optimal curing results:
Apply Curing Compound Immediately
- A widely used method in KSA projects due to speed and efficiency:
- Spray chemical curing compounds on the surface right after finishing.
- These form a membrane that reduces moisture evaporation.
- Avoid application in extremely hot conditions without shade, as solvent‑based compounds can evaporate quickly.
Water Curing (Wet Methods)
Especially effective for large slabs and structural components:
- Fogging/Misting: Keeps the surface cool and moist without washing cement off.
- Ponding: Water is held on the surface where possible — great for slabs and flatwork.
Water curing is ideal when temperature control is necessary — for example in peak summer months when daytime temperatures exceed 40°C.
Wet Coverings
Use moist burlap, cotton mats, or polypropylene fabrics:
- Keeps surface damp.
- Works well with wet curing methods.
- Helps regulate surface temperatures.
This method is especially useful when water supply is limited or difficult to manage on site.
Insulating Blankets or Thermal Covers
In cooler months or night times, cover concrete with insulating blankets to minimize temperature differentials that cause thermal cracking.
Expansion Joints: Relieving Stress to Control Cracking
Even with proper curing, concrete will expand and contract. Expansion joints (also called movement joints) are intentional gaps that allow this movement without creating random cracks.
Why Expansion Joints Are Essential
In large slabs, sidewalks, pavements, and building floors:
- Concrete undergoes thermal expansion during the hot Saudi summer and contracts at night — creating stress.
- Without expansion joints, these stresses are transferred into the slab, causing unwanted cracking.
Where to Place Expansion Joints
The placement of expansion joints depends on:
- Slab size and shape
- Exposure to sunlight
- Adjacent structures
- Reinforcement layout
As a rule of thumb:
- Short side spacing: Joints should be placed at intervals equivalent to 24–36 times the slab thickness (in mm) — adjusted for local practice and design codes.
- Near walls and columns: Always ensure joints are located where slabs meet fixed restraints.
- Change in slope or geometry: These spots are high‑stress zones and need joints.
Expansion Joint Materials and Installation
Success depends on using the right materials:
Compressible Fillers
Placed under the joint to absorb movement and prevent concrete from locking against subgrade or adjacent slabs.
Sealants
Flexible sealants like polyurethane or silicone prevent water and debris from entering joints, which can otherwise cause deterioration.
Backer Rods
Used beneath sealants to control depth and allow proper sealant movement.
Common Mistakes to Avoid
Even with the right intention, mistakes happen:
- Skipping curing because the surface looks hard.
Concrete can appear hard while still losing moisture internally. - Ignoring wind and sun exposure.
Open sites without shading accelerate evaporation. - Incorrect joint spacing.
Too wide and cracks appear between joints; too close and joints become maintenance burdens. - Poor joint detailing.
Improper depth or sealant selection compromises performance. - Monitoring and Maintenance
Concrete performance doesn’t stop at placement. Regular inspection helps catch issues before they worsen.
Recommended Checks
✔ Visual inspection of slab surfaces
✔ Monitoring cracks around joints
✔ Checking sealant condition
✔ Observing joint movement behavior
Case Example: Concrete Work in Riyadh vs Jeddah
Saudi Arabia’s diverse climate means strategies differ by region:
Riyadh
- Hot, dry, with large temperature swings.
- Focus on rapid curing and evaporation control.
- Use of shade structures and misting systems.
Jeddah
- Humid coastal climate.
- Moisture retention is easier — but corrosion and salt exposure are concerns.
- Waterproofing and sealants are critical alongside curing.
Key Takeaways
Concrete cracking is not inevitable — it’s preventable with the right approach.
✔ Proper curing improves strength, minimizes shrinkage, and reduces cracks.
✔ Expansion joints absorb movement and protect slabs from stress.
✔ Climate and project specifics matter — especially in Saudi Arabia’s diverse regions.
✔ Planning, execution, and follow‑up inspection are all part of best practice.
Final Thought
Avoiding cracks isn’t just about aesthetics — it’s about durability, safety, and long‑term performance. Whether you’re pouring a residential driveway in KSA or constructing a major infrastructure slab, curing and expansion joints are your strongest defense against the forces that cause concrete to fail.
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