---
title: "Properties of mortar"
subject: "Civil Engineering Materials"
chapter: 6
key: "semester_3/civil_engineering_materials:properties-of-mortar"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/properties-of-mortar
site: BCT Engineering
---

# Properties of mortar

Civil Engineering Materials · Chapter 6: Mortar

- Asked in: 2081 Baisakh, 2 marks; 2074 Chaitra, 1 marks; 2074 Asoj, 2 marks (asked 3 times)
- Video: [Properties and Proportion of Cement Mortar](https://www.youtube.com/watch?v=wfI19Jq0y1o) — construct SKILLS
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/properties-of-mortar
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-6

## Question

Write down the properties (characteristics) of good (cement) mortar.

## Short answer

Good cement mortar should be workable, bond firmly to masonry units, and possess adequate compressive strength (e.g., 5-10 MPa for 1:4). It must retain water, set without excessive shrinkage, be durable and impermeable, and provide an economical finish free of efflorescence.

## Answer

A good cement mortar should have the following properties:

1. **Workability:** it should be easy to mix, spread and use, and plastic enough to fill the joints completely.
2. **Adhesion (bond strength):** it should stick firmly to bricks and stones.
3. **Strength:** it must have enough compressive strength (for example 5-10 MPa for 1:4 mix, as required) to carry loads from the masonry.
4. **Durability:** it should resist weathering, frost and chemical attack.
5. **Water retentivity:** it should retain water long enough to prevent the masonry units from sucking it out.
6. **Setting:** it should set neither too fast nor too slow; it should not shrink or crack.
7. **Impermeability:** it should resist moisture penetration.
8. **Economy and appearance:** it should be cheap and give a good finish; it should be free from efflorescence-causing salts.
9. **Mobility:** it should flow under the trowel and fill all spaces.

## Check yourself

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

1. Workability of mortar means:
   A. Easy to mix, spread and fill joints
   B. High price
   C. Dark colour
   D. Slow setting
   Answer: A. Plastic enough to use. (Key point: Workability)

2. Water retentivity ensures:
   A. Mortar leaks
   B. Mortar does not lose water to masonry units
   C. Faster drying
   D. More shrinkage
   Answer: B. Retains water long enough. (Key point: Water retentivity)

3. Good mortar should:
   A. Set instantly
   B. Never set
   C. Neither set too fast nor too slow, and not shrink or crack
   D. Crack
   Answer: C. Also durable and economical. (Key point: Setting)

## Related in Civil Engineering Materials

- [Cement and mud mortar properties, uses](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Acement-mud-mortar-properties-uses) — Civil Engineering Materials, chapter 6
- [Cement mortar versus lime mortar](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Acement-vs-lime-mortar) — Civil Engineering Materials, chapter 6
- [Steps of applying cement mortar](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Asteps-applying-cement-mortar) — Civil Engineering Materials, chapter 6
- [Stepwise preparation of cement mortar](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Astepwise-preparing-cement-mortar) — Civil Engineering Materials, chapter 6, asked 4×
- [Precautions while applying cement mortar](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Aprecautions-applying-cement-mortar) — Civil Engineering Materials, chapter 6, asked 3×
- [Mud mortar versus cement mortar](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Amud-vs-cement-mortar) — Civil Engineering Materials, chapter 6

## Related in other subjects

- [Mortar properties; cement and sand for 10 cum](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Amortar-quantity-10cum) — Building Technology, chapter 3
- [Detailed specification of cement sand mortar 1:4](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Adetailed-spec-cs-mortar-1-4) — Construction Management, chapter 12, asked 2×
- [Detailed specification of cement sand mortar 1:6](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Adetailed-spec-cs-mortar-1-6) — Construction Management, chapter 12, asked 2×
- [Preparing cement mortar by manual process](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Amortar-prep-manual) — Building Technology, chapter 3, asked 2×