---
title: "Define permeability in brief"
subject: "Civil Engineering Materials"
chapter: 1
key: "semester_3/civil_engineering_materials:property-permeability"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/property-permeability
site: BCT Engineering
---

# Define permeability in brief

Civil Engineering Materials · Chapter 1: Introduction to Civil Engineering Material

- Asked in: 2080 Baisakh, 1 marks; 2078 Kartik, 0.5 marks (asked 2 times)
- Video: [Concrete Permeability](https://www.youtube.com/watch?v=EwlzCt6ipWY) — Spray-Lock Concrete Protection
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/property-permeability
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-1

## Question

Define permeability as a property of materials.

## Short answer

Permeability is the property that allows water, air or other fluid to pass through under pressure, depending on pore size and interconnection. Sand and gravel are highly permeable, while dense concrete and clay are nearly impermeable, needed low for dams and water tanks.

## Answer

**Permeability** is the property of a material that permits water, air or other fluid to pass through it under pressure. It depends on the size and interconnection of the pores. Sand and gravel are highly permeable, while dense concrete and clay are nearly impermeable. Low permeability is needed in dams, water tanks and basements.

## Check yourself

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

1. Permeability is the property that permits
   A. fluid such as water to pass through under pressure
   B. heat to flow
   C. moisture to be absorbed from air only
   D. cracks to heal
   Answer: A. Permeability concerns passage of fluid through pores. (Key point: Definition)

2. Permeability depends on
   A. colour of the material
   B. size and interconnection of the pores
   C. its hardness
   D. its melting point
   Answer: B. The pore size and interconnection control it. (Key point: Dependence)

3. Low permeability is needed in
   A. gravel drains
   B. filter beds
   C. dams, water tanks and basements
   D. sand filters
   Answer: C. Water-retaining structures need low permeability. (Key point: Need)

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