---
title: "Use of hollow concrete block"
subject: "Concrete Technology and Masonry Structure"
chapter: 7
key: "semester_5/concrete_technology_and_masonry_structure:hollow-concrete-block-use"
source: https://www.bctengineer.com/q/semester_5/concrete_technology_and_masonry_structure/hollow-concrete-block-use
site: BCT Engineering
---

# Use of hollow concrete block

Concrete Technology and Masonry Structure · Chapter 7: Introduction to masonry structures

- Asked in: 2080 Bhadra, 2 marks
- Video: [Hollow Concrete Block Masonry #hollow concrete block #concrete blocks #gtuexam @CivilTutor](https://www.youtube.com/watch?v=bNGwjQrjZOw) — Engineering with Mindfulness
- 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/hollow-concrete-block-use
- Whole chapter: https://www.bctengineer.com/md/semester_5/concrete_technology_and_masonry_structure/chapter-7

## Question

Describe the use of hollow concrete block.

## Short answer

Hollow concrete blocks are used for load-bearing and non-load-bearing walls, partitions, parapets, and infill in RC frames. Their cores can be filled with grout and reinforcement for earthquake-resistant masonry.

## Answer

**Hollow concrete blocks** are precast concrete units with one or more large voids (cores), usually about 25 to 50 percent of the gross volume. They are made of cement, sand and small coarse aggregate (stone chips up to about 10 to 12 mm).

Uses:

- Load-bearing and non-load-bearing walls of residential and industrial buildings, and infill in RC frames.
- Partition walls, boundary walls and parapets.
- Reinforced masonry: the cores can be filled with grout and steel bars for earthquake resistance.

Because they are large, light and uniform, they are quick to lay, need less mortar, give good thermal and sound insulation and reduce the dead load.

## Check yourself

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

1. What fraction of gross volume do the cores of hollow concrete blocks usually form?
   A. 5 to 10 percent
   B. 80 to 90 percent
   C. 40 to 50 percent
   D. Zero
   Answer: C. Large voids give lightness and insulation. (Key point: Voids)

2. How can hollow blocks resist earthquakes?
   A. Cores filled with grout and steel bars
   B. By filling with water
   C. By removing mortar
   D. By stacking dry
   Answer: A. This forms reinforced masonry. (Key point: Reinforced use)

3. Which is a benefit of hollow blocks?
   A. More mortar needed
   B. Quick laying, less mortar and reduced dead load
   C. Higher dead load
   D. Poor insulation
   Answer: B. They are large, light and uniform. (Key point: Benefits)

## Related in Concrete Technology and Masonry Structure

- [Hollow blocks and compressed earth blocks](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Ahollow-block-compressed-earth-block) — Concrete Technology and Masonry Structure, chapter 7

## Related in other subjects

- [Spacing for 4×5 pile group, block failure](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Apile-group-20-piles-block-failure) — Foundation Engineering, chapter 8
- [Comparison of masonry units](https://www.bctengineer.com/question.md?key=semester_5%2Fdesign_of_timber_and_masonry_structures%3Amasonry-units-comparison) — Design of Timber and Masonry Structures, chapter 4