日本大学生産工学部研究報告 A
2024 年 ６ 月 第 57 巻 第 １ 号

Document

State of the Art of Non-Destructive Testing Methods for Concrete
Structures in Japan
Noboru YUASA＊（Received February 6, 2024）

Keywords: Concrete Structure, Non-Destructive Testing Method, Strength, Deterioration, Moisture Content

those standardized by the Japan Non-Destructive

1. Introduction

Inspection Association, and ﬁnally the future prospectsof non-destructive testing.

Interest in "diagnosis" of actual reinforced concrete

2. Heterogeneity of structural concrete

structures has increased recently in Japan, with the shift
from "scrap and build" to "construction of a long-life,
resource-recycling society", and many non-destructive

Many of the non-destructive tests are carried out by

tests have been developed, maintained and used. The use

approaching from the concrete surface. If a test specimenof φ 100mm concrete core sampling is evaluated as ais prepared in a laboratory and fully cured in water ordestructive test although it is on a small scale andsealed, a little difference in quality between the surface

reliable. Destructive test involves large-scale work andlayer and the inside of concrete can be assumed.

repairs, leading to high cost burden without obtaining a

However, concrete in the actual construction is often

large amount of data, and its information tends to be ademolded in early stages where the water evaporates

single point

significance. Although non-destructivefrom the concrete surface and the hydration of the surface

testing allows evaluation using multiple data, it is not alayer stagnates compared to the inside leading topanacea, and the reality is that, in many cases, we haveheterogeneity in the depth direction. Fig. 1 shows theno choice but to rely on destructive testing in the end,

moisture content distribution inside concrete, and Fig. 2

considering accuracy first. If universal physicalshows the distribution of total pore volume1). The surface

properties can be directly tested, there is no problem but

layer of concrete has a lower moisture content than thethe important point of non-destructive testing is theinside and a coarse pore structure. The range is within 5

estimation of a property by testing the other properties

cm in depth in general concrete with a water-cement ratiothat closely related to the target property. The user'sof 0.6 or less, but it extends over a deeper layer in theunderstanding of existing test methods is more important

low quality concrete. Even a block of concrete isthan further or new development of test methods.

heterogeneous, and the strength of concrete varies

For a better understanding of non-destructive testing,throughout the depth as shown in Fig. 3 1)2). Furthermore,this article first introduces the actual conditions of

because the ingress of deterioration factors such asconcrete structures, and then explains the current state ofcarbon dioxide gas, chloride ions, and sulfuric acid gas

existing non-destructive testing methods, focusing on

from the surface and frost damage with large temperature＊

Professor, Department of Architecture and Architectural Engineering, College of Industrial Technology, Nihon
University
─ 11 ─

Fig. 1 Changes in water content distribution in concrete during drying of concrete1)changes are more pronounced in the surface layer, theproperties of concrete change chemically and physically

3. Standards of the Japanese Society for
Non-Destructive Inspection (JSNDI)
The Japanese Society for Non-Destructive Inspection

from the surface layer. It is not hard to imagine that a

conducts academic surveys and research activities incomplex heterogeneous state is formed.
It should be noted that the measured value of non-Japan and overseas across all areas of non-destructive

destructive testing approaching from the surface more
reﬂects the difference in quality between the surface
layer and the interior. As mentioned above, in nondestructive testing, it is often the case that the index or
physical property value to be measured is inferred bymeasuring other physical properties of concrete that areclosely related to it. Table 1 and Table 2 respectively
summarize the effects of water content and pore structure(porosity) on various physical properties of concrete,
which are often handled in nondestructive and microdestructive tests3). These effects should be considered in
the evaluation and interpretation of non-destructive test
results.

Fig. 2 Distribution of effective total pore volume1)

Fig. 3 Distribution of compressive strength from the surface of concrete structure1)
─ 12 ─

Table 1 Effect of moisture content on physicalproperty values of concrete3)

Table 2 Effect of porosity on physical property
values of concrete3)

Table 3 NDIS :Standards of the Japan Non-Destructive Inspection Association

testing, inspection and evaluation.
Table 3 shows a result that have been or being
standardized by the "Department of Non-Destructive
Testing of Reinforced Concrete Structures" working
group. Table 4 shows the characteristics of the nondestructive testing methods for strength that have been
proposed so far.
3.1 Use of small diameter coreFig. 4 Small sized cores4)

Taking a φ 100mm core sampling from a structure as
destructive, the use of a small diameter core (Fig. 4) has

Various tests such as JIS for strength stipulate the use

been regarded as non-destructive testing in terms ofof cores with a diameter three times greater than the

reduction of the degree of rupture.

maximum diameter of the aggregate. Because the 1981
Seismic Design Code currently enforced in Japan─ 13 ─

Table 4 Characteristics of test methods applicable to strength evaluation of concrete structure─ 14 ─

Fig. 6 Effect of diameter of sampled core on test
method for unit cement amount of hardened
concrete with sodium gluconate6)

Fig. 5 Core drillng

Fig. 7 Relationship between total chloride ion content of 100 mm core and small diameter core8)

requires the distance between column ties and beamwith a diameter less than three times the aggregate

stirrups less than 10 cm, where core sampling is difﬁcult

diameterwithout breaking reinforcing bar. Unlike the JIS method,strength of small-diameter concrete cores" (NDIS3439)

the small-diameter core can be applied to columns andenacted in November 2022. This NDIS can use coresbeams with narrow ties and stirrups, and can avoid heightwith diameters between 18 mm and 60 mm.

was the "Method for testing compressive

and reinforcing bar corrections. In addition, since the

The advantage of adopting a small-diameter core

specimen is small, the strength distribution can bemethod is that it is easy to extract cores (Fig. 5) andevaluated from the surface layer in the depth direction of

repair in a short time contributing to the reduction of test

4)5)

concrete structure . However, without understanding

costs.

the inhomogeneity of structural concrete as shown in Fig.

Because of these advantages, the small diameter core

3, sampling only on the surface layer and testing as amethod has been adopted to "The method for unit cement

specimen will not represent the strength of the concrete

content in hardened concrete with sodium gluconate

structure. It is necessary to pay attention to themethod (NDIS 3422)" and "Simpliﬁed test method for

examination of the sampling method according to thechloride ion content in hardened concrete (NDIS 3433)"

purpose and the use of the results.

standards that have already been established in 2002 andThe ﬁrst standardized strength test methods for cores2017, respectively. The former can be applied to concrete─ 15 ─

Fig. 8 Neutralization measurement using powder
from drilled hole10):NDIS 3419-1999

Fig. 9 Neutralization measurement using powder
from drilled hole10)

using limestone and sea sand, which was previously
inapplicable, in addition to the adoption of smalldiameter cores method6, 7). (Fig. 6)
The latter also showed a method of adopting a small
diameter core8) (Fig. 7), and is applicable to any of thefollowing test stages (1) sample collection, (2) sample
preparation, (3) chloride ion extraction, and (4) chloride
ion measurement with reference to JIS A 1154.
Fig. 10 Measuring method for neutralization depth10)

3.2 Use of drilling
It is extremely difﬁcult to understand the quality ofIn the 1970s, J. W. Figg proposed an air permeability

concrete without observation, measurement, and analysis

test method9) using a drill hole with a diameter of about

during damaging the concrete, or sampling minimum

5.5 mm. In our Nihon University, Professor Yoshio Kasai

amount of real concrete.

regarded it as a non-destructive test, on the premise that a

Fig. 11 Relationship between total chloride ion content of 100mm core and drilling powder8)─ 16 ─

Fig. 13 Rapid air-permeability test12)(The borehole
method)public sector, and has been actually adopted in manysites to date.
11)

Fig. 12 Gathering for drilling powder

Drilling powder can be used as a sampling method for"Simplified test methods for chloride ion content

drill hole with a diameter of 10 mm is allowed. We have

hardened concrete (NDIS 3433)"8)11)(Fig. 11). Drilling

built a system to test the quality of various concrete bypowder also has the advantage of extremely shortusing the hole.

pulverization times prior to the analysis. When collecting"Method of test for neutralization depth of concrete

powder on-site, it is important that the ratio of cement

structures with drilling powder (NDIS 3419)" waspaste and aggregate in the collected "powder" should be

developed under such circumstances. When drilled

the same as that of the targeted concrete. Unlesspowder is dropped onto a ﬁlter paper soaked with 1%

measures are taken such as a cover or suction device as

alcohol solution of phthalein(Fig. 8, Fig. 9), the drill isshown in Fig. 12, it is impossible to collect the entire

stopped immediately after color development, and theamount of powder even in a windless laboratory. Fig. 11

depth of the hole is measured with a depth bar of aalso shows drill diameters of φ 30 mm and φ 25 mm,

10)caliper to determine the depth of neutralization (Fig.

but it was conﬁrmed that hammer drills that can be10). This method is ideal both in simplicity and accuracy.

equipped with a drill blade of φ 20 mm or more are

In Japan, associated with the standardization as NDIS, it

generally large and unable to operate and collect in a

has been accepted by many organizations, including thesimple manner.

Fig. 14 Absorption Test
─ 17 ─

Regarding the air permeability of concrete, "Concrete
Surface Air Permeability Test Method (NDIS 3436)" hasbeen established. In consideration of the accumulation,achievements, and popularization of research, we
standardized the drilling method12)13)(Fig. 13) based on
the idea of J. W. Figg together with the Torrentʼs methodof double-chamber and single-chamber methods. Thesemethods enable the evaluation of neutralization
14)

resistance .

Fig. 15 Image of how ultrasonic waves propagate
in the surface scanning method16)

In addition, regarding the water absorption of concrete,“Concrete Water Permeability/Water Absorption Test
Method (NDIS 3440)" has been established. Similar to
NDIS 3436 for air permeability, multiple test methods
such as SWAT, GWT, and drilling methods15)(Fig. 14)
are standardized.
3.3 Approach to concrete surfaces
Tests approaching to concrete surfaces are often easy
to apply and can be truly non-destructive in some cases,
but there are limits to directly evaluating the desired
quality. In addition to the difﬁculty of assessing internal
quality from the surface, as already mentioned, it is
difﬁcult to ensure reliability by indirect estimation with

Fig. 16 Measurement of shock elastic waves by
surface scanning method17)

other related qualities.
"Method of elastic wave test for concrete structures(NDIS 2426)" stipulates the application of ultrasonicwaves and shock elastic waves to concrete structures.
The surface scanning method16)(Fig. 15, Fig. 16), in
which the sensors on the transmitting side and theFig.17 Conception diagram of Leeb

receiving side are separated from each other on the samestraight line, is presented. It refers to quality evaluation

ratio of the repulsion speed to the penetration speed,of compressive strength with special attention to thewhich is indexed as the "rebound speed ratio" in the same

inhomogeneity from the surface to inside. In the impact

way as the rebound degree of conventional reboundelastic wave method, waveforms when impact is applied

hammers. However, in the current JIS A 1155, theto the surface are analyzed, and the contact time, thestructure of the rebound hammer including the mass ofenergy ratio between the penetration process and thethe weight, its movement distance, the radius of therepulsion process, etc. are used as indicators of the

impact plunger top, the spring constant and the impact

17)

energy is strictly, and the Silver Schmidt Hammer isdegree of concrete surface deterioration .
In 2003, "Method of measurement for rebound number

considered out of this standard. However, ASTM, BN,on surface of concrete (JIS A 1155)" was enacted forand EN do not speciﬁed the structure of the reboundmeasuring the rebound number of concrete, while

hammer at all, and the index of the rebound velocity ratio

estimation of strength from the results of reboundcan be interpreted as the applicable range of these

18)19)20).

standards. Therefore, the Japan Society for Non-In the 2000s, the "Silver Schmidt Hammer" wasDestructive Inspection has been standardized "Method

invented and commercialized in Japan. Unlike the degree

for measuring the repulsion velocity ratio of concretemeasurement is outside the scope of this standard

18)of rebound, this is used to estimate strength using the(NDIS 3438) as a supplement to ASTM, BN, EN and─ 18 ─

Fig. 18 Scratching test apparatus

Fig. 19 Scratches

Fig. 21 Scratch on the side of the coreFig. 20 R elationship between compressive strengthand scratch width

2100 to 2300 N•mm of the rebound hammer, themeasuring instrument is compact and easy to measure,and the measurement can be performed if themeasurement points are separated by 3 mm or more, andJIS.
In establishing the NDIS 3438, the Leeb hardness

it is less subject to restrictions on the size and shape oftester, which has been actually used by several concrete

the specimen. At Nihon University, this Leeb Hardness

researchers and practitioners in Japan, should also be

Tester D type is applied to concrete and proposed as aused within this standard. The Leeb hardness tester istest method for estimating the compressive strength oforiginally standardized as a method for measuring theconcrete21). It has been confirmed that the measured

hardness of iron in "Standard Test Method for Leeb

repulsion velocity ratio reﬂects the quality of concrete up

Hardness Testing of Steel Products (ASTM A 956)". As

to a surface layer of 3 mm. It is also recognized that theshown in Fig. 17, an impact body with a test tip of 3mm

degree of repulsion of Rebound Hammer NR reﬂects thein diameter is made to collide with the specimen surface

quality of concrete up to 1 to 2 cm deep. Moreover, in theat a predetermined speed, and the rebound speed ratio iscase of early-age and low-strength concrete, it is pointed

obtained from the impact speed and rebound speed.

out that the rebound hammer NR leaves an indentation,

Features of the Leeb Hardness Tester D type are that thebut the Leeb Hardness Tester D type can realize a

impact energy is as small as 11.5 N•mm compared to thecompletely non-destructive test because the energy is─ 19 ─

Fig. 22 C onsidering the quality of concrete from the pore structuresmall. Currently, the Leeb Hardness Tester is outside thescope of NDIS 3438, but we hope to make it applicable
to NDIS 3438 in the near future.

4. Topics on the non-destructive inspection
technology in Japan toward NDIS
Here, we will introduce non-destructive inspection
technologies and topics that are currently attracting
attention, such as the Japan Non-Destructive Inspection
Society's veriﬁcation, although discussions and work on
Fig. 23 Relationship between effective pore volumeof 0-1cm layer and ease of neutralization30)

NDIS have not started yet.
4.1 Scratching the surface - Scratch method
This is a method of estimating the strength of theconcrete from the width of the scratch by pressing a
speciﬁed pin against the concrete surface with a speciﬁedload (Fig. 18). The measured wound width (Fig. 19) is
made to correspond to the relation (Fig. 20) between thewound width and the compressive strength obtained inadvance. It is possible to estimate the strength
development of concrete before demolding, but if it issubjected to drying after demolding and to deterioration
due to neutralization as shown in Fig. 3, the internal
strength cannot be estimated, so care must be taken when
applying it.
After the scratch tester was approved by the Japan

Fig. 24 Relationship between effective pore volume
and scaling31)

Society for Finishing Technology 22) as a tool for

scratching the side of the extracted core on site (Fig. 21)

evaluating the hardness of ﬂoor slabs, Nihon University

has also been proposed, demonstrating the effectivenessorganized it as a strength development and surfaceof rapid evaluation at the core extraction sites25).

strength test method for structural concrete23). Based on
this result, the test method has been adopted in the

4.2 Microstructure inspection of small concrete
pieces - Pore structure method“Methods and Grades for Various Quality Measurements
and Grades of Concrete Subfloor Surface Layers''

In the ﬁeld of medicine, tissue tests and blood tests are

established by the Japan Floor Construction Technology

used to diagnose many diseases, on the other hand at our

24)

Research Council . A system for evaluating strength by

Nihon University, measurement and analysis of pore─ 20 ─

Fig. 25 Deteriorations of reinforced structure Carbonation
Table 5 Role of water and damage degree in the deterioration
mechanisms32)

Fig. 26 E ffects of driving rain on the corrosion of rebar due to carbonation32)
─ 21 ─

Fig. 27 F reeze damage imit
water saturation33)

Table 6 Types and characteristics of water content measurement method applicable to structures─ 22 ─

structure with small concrete pieces has been conductedusing the mercury intrusion porosimeter to evaluatevarious qualities of concrete26).
The compactness of the concrete structure (porestructure) directly determines the strength, material
permeability and durability of the concrete. The samples
used to measure compactness (pore structure) by the
mercury intrusion porosimeter is a granular piece ofconcrete with a diameter of 2.5 to 5.0 mm capable ofbeing sampled as a small core, broken piece and crashedconcrete debris from the earthquake suffering area.
An important consideration when applying mercury

Fig. 28 E xisting studies and the principles of measuring
water content32)

intrusion porosimeter (Fig. 22) to concrete is that many
ordinary aggregates have negligible porosity comparedto that of hardened cement pastes. In order to clarify theratio of hardened cement paste and aggregate in asample, the hardened cement paste was dissolved inhydrochloric acid, the hardened cement paste ratio was
obtained, and the pore volume of the sample measured
by mercury porosimetry was measured per unit of cement
paste. The results are interpreted in terms of the index ofeffective pore volume converted to the pore volume per

Fig. 29 Embedded Ceramics Sensor by authors32)

unit hardened cement paste27).
Based on this, by analyzing the pore size distribution
and total pore volume, the following properties havebeen evaluated: (1) water-cement ratio 28) •curing
diagnosis1), (2) compression strength estimation (Fig.
3)28)29)2), and (3) neutralization resistance evaluation (Fig.
23)30), (4) chloride ion resistance evaluation, and (5)freeze-thaw resistance evaluation (Fig. 24)31).
4.3 Measurement of "moisture" as the root of allevils - Moisture content test method
Among various forms of degradation(Fig. 25), most of
the degradation involves water32). In other words, mostdegradation does not occur without water (Table 5).

Fig. 30 Relationship between electrical resistanceof concrete and water content by authors32)

Recently, it has been recognized again in Japan that it isextremely important to grasp the water content of concretein the maintenance of buildings (Fig. 26, Fig. 27)34).
So far, there have been many studies (Table 6, Fig.
28-Fig. 35) and commercial measuring instruments. In
the future, it will be necessary to organize and partiallystandardize test methods35)36)37).
4.4 No scaffolding diagnosis – Sampling andremote operation using drone technology
Even if non-destructive testing is applied, structuralFig. 31 Relationship between resistivity of concrete
and water content

─ 23 ─

Fig. 32 Another of embedded electrode32)
Fig. 33 Embedded electronic board sensor36)

diagnosis must be carried out by directly touchingmembers38).
If diagnosis without scaffolding is possible,
maintenance will be dramatically facilitated. There is amovement to expect the realization by means of rapidgrowing drone technology. Inspection can be conductedwith installed cameras and infrared cameras, and even inplaces and parts unable of human approach, it can bequickly done even in an emergency. It is expected to
install the test equipment on the drone and remotely
control it to measure the degree of rebound of a reboundhammer, though security of the reaction force will be anissue.

Fig. 34 Electrodes applicable to the bore holes

Although in Japan, the hurdles for permission from therelevant ministries seem to be extremely high (in an

maintenance practice.

impression of flying the blade), the technology thatmounts the drill and core machine, collects the drill

4.5 Monitoring without wiring - Utilization of RFID
technology

powder sample or core from the test target part andreturns should be developed. It can be applied to

Non-destructive testing is a technology used inneutralization depth tests and chloride ion content tests

monitoring, and improvements in monitoring technology

for long bridges and high-rise buildings, and we are

greatly affect the development and spread of non-confident that this will bring about innovation indestructive testing technology.

Fig. 35 Distribution of water content in concrete by inserted electrodes32)
─ 24 ─

Table 7 Simplicity of research and testingFig. 36 T est procedure and required simplicity for chloride ion test in
NDIS 3433

RFID (Radio Frequency IDentiﬁcation) is driven only

to a RFID communication range for a periodic inspection.

by radio waves from the outside, so it does not requireThis is also in the control of regulations for the drone

39)

battery replacement and can be buried for a long time .

communication output in Japan leaving some points to be

If this technology is applied, data such as temperature,

resolved, but the future technological development andmass water content and strain can be sensed without

relaxation of approvals and licenses by the government

wiring using RFID sensors embedded in concrete inare expected.

39)

advance . A multiple data can be obtained at the sametime simply by holding the device up. If this technology
and drone technology are used in combination, it is

5. Scope of non-destructive testing in Japanand "micro-destructive testing"possible to obtain data on maintenance of long bridges
and high-rise buildings when approaching by drone close─ 25 ─

When speaking "non-destructive testing" of reinforced

concrete structures, "simplicity" is always behind the

6. Concluding remarks

word "non-destructive", while "simplicity" and "nondestructive" are essentially separate discussions. Table
7 summarizes the "simplicity" required for surveys and40)

Compared to destructive testing, non-destructive

tests . It can be said that, "Simpliﬁed test method fortesting is not just a low-level deterioration investigation

chloride ion content in hardened concrete (NDIS 3433)",

test. Recent development and organization of non-deals with "simplicity" as "non-destructive test" in every

destructive testing seems to bring about an essential

part of the standard (Fig. 36).

soundness diagnosis system that could not be done withIn the ﬁelds of civil engineering, construction andmaintenance, from a broader perspective, "non-destructive testing alone. In some cases, diagnosis is
impossible without non-destructive tests.

destructive testing" should be treated as a term that
includes "simplicity".

An appropriate test method should be chosen tobalance the required accuracy, tolerance for destruction,

In the recent situation of Japan, it seems that theand acceptable cost for diagnostic purposes.

keyword of "micro-destructive testing" is recognizedSociety expects test methods of easy, inexpensive,

separately from "non-destructive testing". When we

non-invasive, and capable of accurately assessing the

proposed a neutralization depth test, air permeability test,

quality of concrete. Even in the future, it will still be

and water absorption test with a drill as a non-destructive

difﬁcult to ﬁnd a test method that satisﬁes all the above

test, there were opinions and discussions as to whether

requirements, while it may become an age capable ofthe test using a drill could be called a "non-destructive

evaluating the quality of concrete in structures whentest." Therefore, the keyword "micro-destructive testing"properly understand, select and apply testing methods

was created in Japan.

according to the objectives.

Although the deﬁnition of "micro-destructive testing"Disclosure

is not publicly deﬁned, tests using small-diameter coresof φ 50 mm or less and drills are said to fall under thiscategory. However, at the time when we considered drillThis paper is based on the content published Japanese

tests to be non-destructive tests, we had no doubt thatcommentary40) and41), and has been reconstructed as antests that left scratches were also considered "non-English version by changing the structure and adding thedestructive tests" but acceptable range has been narrowed

latest content, with the aim of disseminating it overseas.

later.

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2014.11

for Non-Destructive Inspection, Symposium on Non-

21) Akira Nonaka, Noboru Yuasa, Kazuhiro Mitani,

Destructive Testing Method for Concrete Structure,
Vol.2, pp.49-54, 2006.8 (in Japanese)

Seiji Kanamori: Proposal of Testing Method forConcrete Strength Using Equotip, Journal of29) Toshiyuki Yoshino: Strength Estimation Formula

Technology and Design, Architectural Institute ofUsing Pore Index of Concrete and its Application,

Japan, Vol.23, No.54, Publication decision, 2017.6

Doctoral Dissertation, Hokkaido University, 1996

(in Japanese)(in Japanese)22) Tsutomu Asami: Study on Rapid Measurement30) Noboru Yuasa, Yoshio Kasai, Isamu Matsui:

Method for Surface Hardness of Substrate Concrete

Neutralization Resistance of Surface Concrete,

Floor, Japan Society for Finishing Technology,

Proceedings of the 25th Cement and Concrete

FINEX, Vol.9, No.54, pp.22-26, 1997.10 (inResearch Symposium, pp.149-154, 1998.10 (inJapanese)Japanese)23) Noboru Yuasa, Yoshio Kasai, Isamu Matsui, Sachiyo31) Noboru Yuasa, Yoshio Kasai, Isamu Matsui, Eiji

Shinozaki: Testing Method for Surface Strength ofKamada: Freeze-Thaw Resistance of Concretes

Concrete Slab, 5th International Colloquium

Subjected to Drying at Early Ages, Challenges ofIndustrial Floors '03, Vol.1, pp.143-148, 2003.1

Concrete Construction, Concrete Technology Unit,

24) Eitetsu Ono, Yutaka Yokoyama, Susumu Nagahashi,

University of Dundee, Concrete for Extreme
Conditions, pp.437-446, 2002.9

Shigeo Kajiura, Takeshi Yokoi, Noboru Yuasa,
Naohito Hana, Kazuo Omata: Proposal of Rapid32) Noboru Yuasa: Effect of Water on Building

Measurement and Evaluation Method on Quality for

Deterioration, Proceedings of the 6th China-Japanvarious qualities of Surface Layer Concrete Ground-Korea Symposium on WATERPROOFING

Work, Journal of Technology and Design,

TECHNOLOGY, pp.101-104, 2017.11 (in Japanese)

Architectural Institute of Japan, No. 18, pp.11-16,

33) G. Fagerlund: The Critical Degree of Saturation

2003.12 (in Japanese)

Assessing the Freeze/ Thaw Resistance of Concrete,25) Natsuko Nishikawa, Masao Yamane, Yasuo

Material and Construction, vol.10, No.58, pp.217253, 1978

Tanigawa, Kazuo Suzuki: Research on strength
estimation methods for low-strength concrete using34) "Reconsideration of the Limit State of Reinforced

various non-destructive testing methods -Part 2:

Concrete Structure- Is Neutralization Lifetime?",Scratch method-, Summaries of Technical Papers ofPanel Discussion of Materials and Construction

Annual Meeting A-1, Architectural Institute ofSection, Architectural Institute of Japan, 2017.9 (inJapan, pp.241-242, 2007.8 (in Japanese)

Japanese)

26) Noboru Yuasa, Yoshio Kasai, Isamu Matsui, Sachiyo35) Noboru Yuasa: Non- destructive Testing Methods

Shinozaki: Concrete Quality Evaluation Method

for Water Content of Concrete: State-of-the-Art in

Based on Pore Structure, Concrete testing method,

Japan, Seventh US-Japan NDT Symposium, invited

Architectural Institute of Japan, Vol.2, pp.67-70,

paper, WEB, 2022.8

2003.11 (in Japanese)36) Noboru Yuasa: Experimental Study on Meaning of27) Eiji Kamada, Masayuki Tabata, Toshiyuki Yoshino:

Display Value of Press High-Frequency Capacitive

Development of Method for Estimating Strength of

Moisture Meter, Proceedings of the 39th Cement

Structural Concrete Using Pore Structure, Grant-in-and Concrete Research Symposium, pp.75-80,

Aid for Scientific Research "Experimental Research"2012.10 (in Japanese)

Research Result Report for Japan Government,37) Rikiya Takahashi, Kenta Takahashi, Noboru Yuasa:

1978-1979 (in Japanese)

Development of Technology for Measuring Internal28) Takashi Sasaki, Noboru Yuasa, Yoshio Kasai, Isamu

Moisture Content Distribution in Concrete Using

Matsui: Testing Method for Water-cement Ratio andPrototype General-purpose Embedded Substrate

Compressive Strength with Effective Absorption

Electrode Sensor, Proceedings of the Japan─ 28 ─Concrete Institute, Vol.46, CD-ROM, 2024.6 (inVol.6, pp.321-324, 2018.8 (in Japanese)40) Noboru Yuasa: State of the Art of Non-Destructive

Japanese)38) Noboru Yuasa: Receiving system for measured

Testing Methods for Concrete Structure, Cement &concrete data on remote site by wireless, Cement &Concrete, Japan Cement Association, No.862，

Concrete, Japan Cement Association, No.749,

pp.4-13，2018.12 and No.863，pp.36-41，2019.1 (inpp.33-38, 2009.7 (in Japanese)

Japanese)39) Natsuki Komoda, Noboru Yuasa, Ryo Matsuyasu,

41) Noboru Yuasa: Futuristic View of "Non-destructive

Masatoshi Kondo, Takumi Aramaki: Evaluation of

Testing" for Concrete Structures, Journal of the

Wirelees Sensor Technology inside Concrete withJapanese Society for Non-destructive Inspection,

Passive Sensor RFID, Japan Society for Non-

Vol.68, No.3，pp.125-131，2019.3 (in Japanese)

Destructive Inspection, Symposium on NonDestructive Testing Method for Concrete Structure,─ 29 ─

日本におけるコンクリート構造物の非破壊検査・最近の動き

湯浅

概

要

日本では，近年，「スクラップ＆ビルド」から「超寿命化・資源循環型社会の構築」への移行にあたり，鉄筋コンク
リート実構造物の「診断」に関する関心が高まり，実に多くの非破壊試験が考案・整備・使用されている。φ100mm
コンクリートコアは，その結果の信頼性は評価されるものの，小規模ではあるが破壊試験とされる。破壊試験と位置づけられる試験は，大がかりな作業や補修を伴い，それがまた高価な費用負担につながることから多数のデータを得ることはできず，点としての情報となる傾向にある。しかし，非破壊試験によれば多数デ－タによる評価が可能である。
しかしながら，非破壊試験は万能ではなく，精度を第一に考えて，やはり最後は破壊試験に頼らざるを得ないことが多いのも実態である。非破壊試験の重要な勘所は，普遍的な物性値をストレートに近い状態で試験・評価できる場合はいいとして，その物性値に関連深いコンクリートの他の物性を測定することにより類推して評価できるかである。だから必然的に万能ではない。更なる試験方法の開発・発展の重要性もさることながら，使用者の既存の試験方法に対する理解こそ極めて重要といえる。
本資料では，非破壊試験のよりよい理解のために，コンクリート構造物の実態を紹介した上で，日本非破壊検査協会
で規格となった試験方法を中心に，日本における既存の非破壊試験の現状を解説し，最後に非破壊試験の将来展望について言及した。

─ 30 ─

昇

Biographical Sketches of the Author
Dr. Noboru Yuasa is a professor of College of Industrial Technology, Nihon
University. He earned his B.Eng. in 1988 from Hokkaido University and M. Eng. in1990 from Tokyo Institute of Technology.
After finishing master course in Tokyo Institute of Technology, he moved to Nihon
University as a research associate. He promoted to a lecturer in 1998, an associate
professor in 2003 and a professor in 2011. He received the degree of Dr. Eng. for “A
Fundamental Study on the Quality of Surface Layer Concrete” in 1998 from Nihon
University.
He has been studied “The surface layer concrete” in the point of view frommoisture content and porosity as life work. And he received The Prize of AIJ 2019
(Research Theses Division) from Architectural Institute of Japan for “A SERIES OFSTUDY ON SURFACE LAYER CONCRETE QUALITY” in 2019.
His current research topics include durability of concrete structures and finishingmaterials, non-destructive testing method, demolition of structures, earthquake
resistance improvement for building of developing country and investigation ofhistorical buildings.
He has been participated in several international research projects for Santuario di
Vicoforte and L'Hangar per dirigibili di Augusta; 2002-03 and 2006-08, Sant'Agostino,
San Silvestro e Torre Civica in L'Aquila; 2010-2014, Italy, Spain, Portugal; 2016-2021.
And, he also participates in “Bhutan Project” by the JST/JICA SATREPS (Scienceand Technology Research Partnership for Sustainable Development).
During he was a lecturer of Nihon University, he was visiting researcher for one
year at University of Dundee, England in 2011.
He is a chairman, secretary or research leader of a lot of committees in
Architectural Institute of Japan, Japan Concrete Institute, Japan cement association,
Japan Society for Finishing Technology and Japanese Society of Non-Destructive
Inspection.

─ 31 ─