---
title: "Importance of non-destructive testing"
subject: "Concrete Technology and Masonry Structure"
chapter: 5
key: "semester_5/concrete_technology_and_masonry_structure:ndt-importance"
source: https://www.bctengineer.com/q/semester_5/concrete_technology_and_masonry_structure/ndt-importance
site: BCT Engineering
---

# Importance of non-destructive testing

Concrete Technology and Masonry Structure · Chapter 5: Testing of concrete and quality control

- Asked in: 2081 Baisakh, 4 marks; 2073 Shrawan, 6 marks; 2071 Chaitra, 6 marks; 2071 Shrawan, 6 marks (asked 4 times)
- Video: [Introduction to Non Destructive Testing of Concrete - Advanced Concrete Technology](https://www.youtube.com/watch?v=T-853btlzCA) — Ekeeda
- Answer checked by Claude Sonnet 5.5 on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/concrete_technology_and_masonry_structure/ndt-importance
- Whole chapter: https://www.bctengineer.com/md/semester_5/concrete_technology_and_masonry_structure/chapter-5

## Question

Explain the importance of non-destructive testing of concrete in civil engineering structures.

## Short answer

NDT evaluates in-situ concrete quality without damage. It allows repeated testing to monitor changes, quickly surveys large areas for defects, assesses old or damaged structures, and checks uniformity, cover, and rebar positions when cube tests are doubtful, reflecting actual condition rather than just control specimens.

## Answer

Non-destructive testing (NDT) assesses the quality and strength of concrete in a structure without damaging it.

**Importance**
- Tests the **actual** in-situ concrete, not only the control cubes, which may not represent the structure's compaction and curing.
- No damage and repeated tests at the same place are possible, so the changes with time can be tracked.
- Quick and cheap; large areas can be surveyed to find weak, honeycombed or cracked zones.
- Assesses old structures for repair, change of use, fire or earthquake damage, and long-term deterioration (corrosion, carbonation).
- Investigates doubts when cube results fail the acceptance criteria (IS 456, Cl. 16), before costly coring or load tests (Cl. 17).
- Checks uniformity, thickness, cover and the position of rebars, and gives a basis for deciding on repair.

## Check yourself

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

1. A main advantage of NDT over control cubes is that it:
   A. Tests actual in-situ concrete of the structure
   B. Gives exact strength
   C. Destroys little concrete
   D. Replaces all design
   Answer: A. Cubes may not represent compaction and curing in the structure. (Key point: In-situ)

2. Which is an advantage of NDT?
   A. Needs coring each time
   B. Repeated tests at the same place can track changes with time
   C. Causes cracks
   D. Only works on new concrete
   Answer: B. No damage, so repeat testing is possible. (Key point: Repeatability)

3. When cubes fail acceptance criteria, NDT is used:
   A. After load tests
   B. Instead of cube tests always
   C. Before costly coring or load tests
   D. Only for steel
   Answer: C. NDT investigates doubts before coring and load tests (Cl. 17). (Key point: Failed cubes)

4. NDT can also be used to:
   A. Change mix design
   B. Increase strength
   C. Cure concrete
   D. Check uniformity, cover and rebar position, and old structure deterioration
   Answer: D. It surveys weak zones, cover, rebars and deterioration such as corrosion and carbonation. (Key point: Other uses)

## Related in Concrete Technology and Masonry Structure

- [Non-destructive testing methods for concrete](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Andt-methods-concrete) — Concrete Technology and Masonry Structure, chapter 5, asked 4×
- [Non-destructive tests for masonry](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Andt-masonry-tests) — Concrete Technology and Masonry Structure, chapter 10, asked 3×
- [Destructive and non-destructive tests in masonry](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Adestructive-ndt-masonry-list) — Concrete Technology and Masonry Structure, chapter 10
- [Destructive tests of concrete](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Adestructive-tests-concrete) — Concrete Technology and Masonry Structure, chapter 5

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- [Non-destructive tests on insulators](https://www.bctengineer.com/question.md?key=semester_8%2Fhigh_voltage_engineering%3Anon-destructive-insulator-tests) — High Voltage Engineering, chapter 7, asked 4×
- [Destructive and non-destructive tests](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Aretrofit-destructive-tests) — Building Technology, chapter 11
- [Non-destructive tests in buildings](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Andt-building) — Building Technology, chapter 11
- [Folds: recognition and civil engineering influence](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Afolds-recognition-and-civil-engineering) — Engineering Geology I, chapter 5