---
title: "Gypsum products and applications"
subject: "Civil Engineering Materials"
chapter: 10
key: "semester_3/civil_engineering_materials:gypsum-products"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/gypsum-products
site: BCT Engineering
---

# Gypsum products and applications

Civil Engineering Materials · Chapter 10: Asphalt, Bitumen, Tar and Miscellaneous Materials

- Asked in: 2081 Chaitra (new course), 2 marks; 2081 Bhadra, 2 marks; 2075 Asoj, 2 marks (asked 3 times)
- Video: [Gypsum products : Source, Uses, Manufacturing](https://www.youtube.com/watch?v=EltkIFnstkQ) — Dr Teeth
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/gypsum-products
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-10

## Question

Write short notes on gypsum products available in the market and their applications.

## Short answer

Plaster of Paris is used for moulds, false ceilings and decorative work. Gypsum plaster provides smooth wall finishes; gypsum board is used for partitions and false ceilings. Gypsum blocks, wall putty and cement additive (2–5% to control setting) are also common.

## Answer

**Gypsum** is hydrated calcium sulphate ($CaSO_4 \cdot 2H_2O$). On heating at about 130–160 °C it loses water to form plaster of Paris ($CaSO_4 \cdot \tfrac{1}{2}H_2O$), which sets quickly when mixed with water.

#### Products available and their applications

| Product | Application |
|---|---|
| **Plaster of Paris (POP)** | Moulds, false ceilings, decorative cornices, ornamental work, finishing coat for walls, joint filling |
| **Gypsum plaster (wall plaster)** | Single-coat internal plaster on brick or concrete; smooth finish without cement |
| **Gypsum board (plasterboard, drywall)** | Partitions and false ceilings; light, fire-resistant, easy to fix |
| **Gypsum blocks and tiles** | Non-load-bearing partition walls and ceiling tiles |
| **Wall putty** | Smooth base for painting |
| **Gypsum as cement additive** | About 2–5% gypsum is added to cement clinker to control the setting time |
| **Gypsum floor screed** | Self-levelling floors |

**Advantages:** fire resistance, good thermal and sound insulation, smooth surface, quick setting. It is not suited to damp areas (unless water-resistant board is used).

## Check yourself

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

1. What happens when gypsum is heated at about 130-160 degrees C?
   A. It becomes cement
   B. It melts into glass
   C. It loses water to form plaster of Paris
   D. It gains water
   Answer: C. CaSO4.2H2O loses water to give CaSO4.1/2H2O. (Key point: Gypsum to POP)

2. Why is 2-5% gypsum added to cement clinker?
   A. To control setting time
   B. To add colour
   C. To increase heat
   D. To reduce strength
   Answer: A. Gypsum controls the setting time of cement. (Key point: Cement additive)

3. Gypsum board is used mainly for what?
   A. Foundations
   B. Load-bearing walls
   C. Partitions and false ceilings
   D. Roads
   Answer: C. It is light, fire-resistant and easy to fix, used for partitions and false ceilings. (Key point: Gypsum board)

4. Gypsum products are not suited to what?
   A. Dry interiors
   B. Damp areas (unless water-resistant board)
   C. Ceilings
   D. Fire protection
   Answer: B. They are unsuited to damp areas unless water-resistant. (Key point: Limitation)

## Related in Civil Engineering Materials

- [Commercial products of timber](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Acommercial-products-of-timber) — Civil Engineering Materials, chapter 7, asked 3×

## Related in other subjects

- [Powder metallurgy process and applications](https://www.bctengineer.com/question.md?key=semester_4%2Fmanufacturing_and_production_processes%3Apowder-metallurgy-process-steps) — Manufacturing and Production Processes, chapter 4