---
title: "Hot climate concreting and curing"
subject: "Concrete Technology and Masonry Structure"
chapter: 3
key: "semester_5/concrete_technology_and_masonry_structure:hot-weather-methods-curing"
source: https://www.bctengineer.com/q/semester_5/concrete_technology_and_masonry_structure/hot-weather-methods-curing
site: BCT Engineering
---

# Hot climate concreting and curing

Concrete Technology and Masonry Structure · Chapter 3: Mix design of concrete and property of green concrete

- Asked in: 2067 Magh (old course), 5 marks
- Video: [Why Curing of Concrete is Important? Concrete Curing Process](https://www.youtube.com/watch?v=APpTjxgVhx8) — Civil Mentors
- 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/hot-weather-methods-curing
- Whole chapter: https://www.bctengineer.com/md/semester_5/concrete_technology_and_masonry_structure/chapter-3

## Question

Explain what appropriate methods are to be adopted and what specific measures are to be taken while concreting and curing in hot climate condition.

## Short answer

For hot-weather concreting, cool ingredients (chilled water, shaded aggregates), use retardering admixtures, place in early morning/evening, and keep concrete temperature below 40°C. During curing, prevent plastic shrinkage with fog spray or film, start moist curing immediately, and cure continuously by ponding or wet coverings for at least10 days (14 days with blended cement), while protecting from heat.

## Answer

Hot-weather concreting (ambient above about 30 to 35 °C, with low humidity or wind) is carried out so that the concrete temperature at placing stays below 40 °C (IS 7861 Part 1, referred to by IS 456 Cl. 14.1) and moisture loss is prevented.

#### Appropriate methods before and during concreting
- Select low-heat cement or Portland pozzolana cement; use a retarding water-reducing admixture so that the W/C does not need to be raised.
- Cool the ingredients: shade and sprinkle aggregate stockpiles, keep water tanks and pipes shaded or white-painted, and use chilled water or crushed ice in the mix.
- Keep the haul short, use covered transit mixers, mix just before placing and avoid delays.
- Cast in the early morning, evening or night.
- Wet the subgrade, forms and reinforcement before casting (with no standing water); use shades and windbreaks.
- Place in thin layers, vibrate properly, and plan joints to avoid cold joints.

#### Specific measures during finishing and curing
1. Prevent plastic shrinkage: use a fog spray or an evaporation-retardant film, or cover with polythene between finishing operations.
2. Begin curing as soon as the surface can take it without being marred.
3. Cure continuously by ponding, wet hessian or sand, or sprinkling; do not let the surface dry even for a short time (wet-dry cycles cause cracking).
4. Alternatively, apply a curing compound or cover with white polythene sheet to reflect heat.
5. Cure for at least 10 days in hot and dry weather (IS 456, Cl. 13.5.1), and preferably 14 days with blended cement.
6. Delay the stripping of forms, protect the concrete from heat and wind, and keep the forms wet.
7. Control joint spacing and keep the temperature difference between the concrete and the air small, to avoid thermal cracking.

## Check yourself

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

1. In hot-weather concreting the temperature of concrete at placing should be kept below:
   A. 25 C
   B. 40 C
   C. 50 C
   D. 60 C
   Answer: B. IS 456 limits placing temperature to 40 C to avoid rapid setting and moisture loss. (Key point: Concrete temperature limit)

2. Which step cools the concrete mix itself in hot weather?
   A. Shading and sprinkling aggregate stockpiles and using chilled water or crushed ice
   B. Heating the mixing water to 60 C
   C. Adding extra water to keep it workable
   D. Using rapid-hardening cement with an accelerator
   Answer: A. Cooling aggregate and water (or ice) lowers the mix temperature; extra water would raise W/C. (Key point: Cooling ingredients)

3. To prevent plastic shrinkage cracks between finishing operations, one should:
   A. leave the surface bare to dry quickly
   B. sprinkle dry cement on the surface
   C. use fog spray, evaporation retardant film or polythene cover
   D. remove forms early to let heat escape
   Answer: C. Stopping surface evaporation prevents plastic shrinkage. (Key point: Preventing plastic shrinkage)

4. IS 456 minimum curing period in hot and dry weather is:
   A. 3 days
   B. 7 days for all cements
   C. 28 days
   D. at least 10 days (14 days with blended cement)
   Answer: D. Hot, dry weather needs at least 10 days; blended cement is extended to 14 days. (Key point: Curing period in hot weather)

## Related in Concrete Technology and Masonry Structure

- [Hot weather concreting: effects, precautions](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Ahot-weather-effects-precautions) — Concrete Technology and Masonry Structure, chapter 3
- [Casting and curing temperature; concreting in Kathmandu](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Acasting-curing-temperature-kathmandu) — Concrete Technology and Masonry Structure, chapter 4
- [Hot weather concreting precautions](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Ahot-weather-precautions) — Concrete Technology and Masonry Structure, chapter 3, asked 2×
- [Cold weather concreting](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Acold-weather-concreting) — Concrete Technology and Masonry Structure, chapter 3

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- [Climate change threat, impact and mitigation](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Acc-threat-impact-mitigation) — Technology, Environment and Society, chapter 3
- [Short note: Climate change mitigation and adaptation](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Acc-mitigation-adaptation-note) — Technology, Environment and Society, chapter 6
- [Climate change gases, impact and mitigation](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Acc-gases-impact-mitigation) — Technology, Environment and Society, chapter 6