C10 vs C35: Understanding Concrete Mix Ratios for UK Construction

When planning a construction project in the UK, choosing the right concrete mix ratio is essential. The two mixes that often come into question are C10 and C35. While both have their place in construction, they serve very different purposes.

In this guide, we’ll break down the differences between C10 and C35, compare their strength, durability, applications, and explain why choosing the right grade can save builders both time and money.

The Basics: C10 vs C35

• C10 Concrete: Low-strength mix (10 N/mm² at 28 days). Used for non-structural applications like pathways, kerbs, and blinding.
  
  

• C35 Concrete: High-strength mix (35 N/mm² at 28 days). Designed for structural applications such as reinforced foundations, walls, and heavy-duty floors.
  

Mix Ratios Compared

C10 Mix Ratio:

• 1 part cement
  
  

• 3 parts sand
  
  

• 6 parts coarse aggregate
  
  

• More workable, less dense
  

C35 Mix Ratio:

• 1 part cement
  
  

• 2 parts sand
  
  

• 4 parts coarse aggregate
  
  

• Denser, more durable, stronger
  

Key Differences Between C10 and C35

1. Strength

C10 provides 10 N/mm², making it suitable for light-duty projects.
C35 offers 35 N/mm², suitable for heavy-duty, load-bearing applications.

2. Cost

C10 is cheaper due to its lower cement content.
C35 is more expensive but long-lasting.

3. Applications

• C10: Pathways, kerbs, blinding layers, light foundations.
  
  

• C35: Structural beams, commercial foundations, driveways, industrial yards.
  

4. Durability

C35 has low permeability and performs well in harsh UK weather.
C10 requires more maintenance and protection in external conditions.

When to Use C10 vs C35 in the UK

• Use C10 when:
  
  

• You need a blinding layer beneath foundations.
  
  

• Building pathways or non-load-bearing surfaces.
  
  

• Budget is a key factor.
  
  

• Use C35 when:
  
  

• Constructing structural foundations.
  
  

• Pouring driveways that bear heavy loads.
  
  

• Building in harsh weather conditions where strength and durability are critical.
  

Conclusion

When comparing C10 vs C35 concrete, it’s clear that each serves a unique role in UK construction. C10 provides affordability and ease of use for non-structural tasks, while C35 delivers strength and durability for heavy-duty work. Builders who choose wisely ensure their projects are both cost-efficient and long-lasting.

Frequently Asked Questions

Q1. Which is better for driveways: C10 or C35?
C35 is the clear winner. C10 is too weak for vehicle loads.

Q2. Is C10 always cheaper than C35?
Yes. C10 requires less cement, making it a budget-friendly choice.

Q3. Can both be used in the same project?
Yes. C10 often serves as a blinding layer, while C35 is used for structural elements.

Q4. How do UK builders decide between C10 and C35?
The decision is based on the intended load, durability requirements, and cost considerations.

Q5. Does C35 last longer than C10?
Yes. C35’s density and strength ensure better long-term performance in UK climates.