---
title: "Aggregate crushing value determination"
subject: "Concrete Technology and Masonry Structure"
chapter: 1
key: "semester_5/concrete_technology_and_masonry_structure:aggregate-crushing-value"
source: https://www.bctengineer.com/q/semester_5/concrete_technology_and_masonry_structure/aggregate-crushing-value
site: BCT Engineering
---

# Aggregate crushing value determination

Concrete Technology and Masonry Structure · Chapter 1: Introduction to concrete and concrete materials

- Asked in: 2080 Baisakh, 3 marks
- Video: [AGGREGATE CRUSHING VALUE TEST || Crushing test ! Crushing test of aggregate ! Test of aggregate](https://www.youtube.com/watch?v=SyOFfoi8Br8) — Crazy Civil Engineering
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/concrete_technology_and_masonry_structure/aggregate-crushing-value
- Whole chapter: https://www.bctengineer.com/md/semester_5/concrete_technology_and_masonry_structure/chapter-1

## Question

Describe the process of determining aggregate crushing value in the laboratory.

## Short answer

Dry 10–12.5 mm aggregate in cylinder, tamp in three layers, apply 400 kN in 10 min, then sieve on 2.36 mm. ACV = (mass passing / total mass) × 100%. Limits: ≤45% for general concrete, ≤30% for wearing surfaces.

## Answer

**Aggregate crushing value (ACV)** measures the resistance of an aggregate to crushing under a gradually applied compressive load (IS 2386 Part 4). It indicates the strength of the aggregate.

#### Apparatus
A steel cylinder of 150 mm diameter with a plunger and base plate, compression testing machine, tamping rod (16 mm dia, 45-60 cm long), balance, IS sieves 12.5 mm, 10 mm and 2.36 mm.

#### Procedure
1. Take aggregate passing the 12.5 mm and retained on the 10 mm sieve, oven-dried at 100-110 °C for 4 hours and cooled.
2. Fill the cylinder in three layers of equal depth, tamping each layer with 25 strokes; level the surface; weigh the sample ($W_1$, about 3 kg).
3. Place the plunger on the sample and position the assembly in the compression machine.
4. Apply the load at a uniform rate so that **400 kN** is reached in 10 minutes; then release.
5. Take the crushed aggregate out and sieve over the 2.36 mm IS sieve; weigh the portion that passes ($W_2$).
6. Repeat with a second sample and take the average.

$$
\text{ACV} = \frac{W_2}{W_1} \times 100\ \%
$$

#### Limits (IS 383)
ACV not more than **45%** for aggregates used in concrete other than wearing surfaces and **30%** for wearing surfaces such as roads and pavements. A smaller value means stronger aggregate.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. The aggregate tested for crushing value passes and is retained on:
   A. Passes 20 mm, retained 12.5 mm
   B. Passes 12.5 mm, retained 10 mm
   C. Passes 10 mm, retained 4.75 mm
   D. Passes 40 mm, retained 20 mm
   Answer: B. Sample passes the 12.5 mm and is retained on the 10 mm sieve. (Key point: Test sample)

2. The load is applied so that:
   A. 400 kN is reached in 10 minutes
   B. 40 kN in 1 min
   C. 100 kN in 1 hour
   D. Constant 400 kN for 10 min
   Answer: A. Uniform rate to 400 kN in 10 min, then release. (Key point: Loading)

3. ACV equals:
   A. W1/W2 x 100
   B. Weight passing 2.36 mm (W2) / original weight (W1) x 100
   C. Weight retained on 2.36 mm / W2
   D. W2 - W1
   Answer: B. Crushed fines passing 2.36 mm over original weight, as a percentage. (Key point: ACV calculation)

4. ACV limit for wearing surfaces is:
   A. 45%
   B. 60%
   C. 30%
   D. 10%
   Answer: C. 45% for general concrete and 30% for wearing surfaces; smaller value means stronger aggregate. (Key point: Limits)

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