Effect of Mechanical Properties of Aggregate on Concrete Properties

1

Presented by: Sagar Dhakal

PAS079BCE098

August 12, 2025

2

CONSTITUENTS OF CONCRETE

Source: worl.data.blog. (2019, April). Concrete mix design diagram

Introduction

• Aggregates are inert granular materials such as sand, gravel, or crushed stone that are mixed with cement and water to form concrete or mortar. They provide bulk, strength, and stability to the final product. Aggregates occupy 60–80% of concrete volume.

​

3

Mechanical properties of aggregates in concrete significantly influence:

- Strength

- Durability

- Workability

Key Mechanical Properties of Aggregate

• Bond Strength
• Strength
• Toughness
• Hardness

​

4

Bond Strength

• Bond strength refers to the adhesion between aggregate surface and hydrated cement paste.
• It is influenced by:�– Surface texture of aggregates (rough texture = better bond)�– Cleanliness and moisture condition of aggregates�– Shape and angularity (angular particles offer better mechanical interlock)
• Strong bond improves:�– Tensile and flexural strength of concrete�– Durability and crack resistance
• Weak bond leads to interfacial failure and reduced overall performance.

5

Strength

• Indicates aggregate strength under compressive loads.
• Lower ACV → Stronger Aggregate → Higher Concrete Strength
• Standard limit for concrete: <30%
• 📌 Impact: Affects the compressive strength of concrete.

6

(Measured by Aggregate Crushing Value – ACV)

7

According to IS 2386 (part IV)

Source: Civiconcepts.com. (October 2019). Aggregate Crushing Value Test Apparatus Diagram

8

Fig: The relationship between ACV of aggregate and compressive strength of concrete.

Source: Research gate; Sharifi, Javad & Nikudel, Mohammad. (2011). The Study of Relationships between Aggregates Properties and Concrete Strength.

• Measures resistance to sudden shocks.
• High impact value = Aggregate prone to break under load.
• Standard limit for pavement concrete: <20%
• 📌 Impact: Influences concrete's toughness and durability under dynamic loads.

9

Toughness

(Measured by Aggregate Impact Value – AIV)

10

According to IS 2386 (part IV)

Source: Civiconcepts, 2019. Aggregate Impact Value Test.

11

Fig: The relationship between AIV of aggregate and compressive strength of concrete.

Source: Research gate; Sharifi, Javad & Nikudel, Mohammad. (2011). The Study of Relationships between Aggregates Properties and Concrete Strength.

(Measured by Los Angeles Abrasion Value – LAAV)

• Measures wear resistance of aggregates.
• High abrasion value = More surface wear.
• Standard limit: <30–50%
• 📌 Impact: Important for pavements and industrial floors.

12

Hardness

13

According to IS 2386 (part IV)

Source: IndiaMART, 2019. Los Angeles Abrasion Testing Machine.

source: Gilson Company, Inc., 2025. Aggregate Abrasion Testing (Part 2): The L.A. Abrasion Test.

Overall Effects on Concrete Properties

14

Practical Applications

• Road Pavements: Need high abrasion resistance and toughness.
• High-Rise Buildings: Require aggregates with high crushing strength.
• Bridges & Dams: Require durable and tough aggregates.

15

Conclusion

• Mechanical properties of aggregates are critical for concrete performance.
• Proper selection leads to durable, strong, and economical structures.
• Always test should be performed and aggregates must be chosen as per design requirements.

16

References

• IS 2386 (Part 4): Methods of Test for Aggregates
• Neville, A.M. – Properties of Concrete
• M.S. Shetty – Concrete Technology
• Sharifi, Javad & Nikudel, Mohammad. (2011). The Study of Relationships between Aggregates Properties and Concrete Strength.

17

18

Thank

you!

dhakalsagar538@gmail.com

Sagar Dhakal