Freezing of water or salt solution in concrete pores is a main cause for severe damage and  significant reduction of the service life. Most of the freeze-thaw (F-T) accelerated tests measure the scaling of concrete by weighting. This paper presents complementary procedures based on the use  of strain gages and ultrasonic pulse velocity (UPV) for measuring the deterioration of concrete due  to freezing and thawing. These non-destructive testing (NDT) procedures are applied to two types  of concretes, one susceptible to F-T damage and the other does not. The results show a good  correlation between scaling and the measurements obtained with NDT. Showing NDT the  advantage to detect before the damage and to perform continuous measuremen

Casati Calzada, María Jesús

Gálvez Ruiz, Jaime

Romero Mendoza, Héctor Leonardo

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NDT for concrete under accelerated freeze/thaw tests and surface scaling

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fib Symposium PRAGUE 2011 
Session 2A-3: Concrete Technology 
 
 341
NDT FOR CONCRETE UNDER ACCELERATED 
FREEZE/THAW TESTS AND SURFACE SCALING 
 
  
Héctor L. Romero Maria J. Casati Jaime C. Gálvez   
Abstract  
Freezing of water or salt solution in concrete pores is a main cause for severe damage and 
significant reduction of the service life. Most of the freeze-thaw (F-T) accelerated tests measure the 
scaling of concrete by weighting. This paper presents complementary procedures based on the use 
of strain gages and ultrasonic pulse velocity (UPV) for measuring the deterioration of concrete due 
to freezing and thawing. These non-destructive testing (NDT) procedures are applied to two types 
of concretes, one susceptible to F-T damage and the other does not. The results show a good 
correlation between scaling and the measurements obtained with NDT. Showing NDT the 
advantage to detect before the damage and to perform continuous measurement. 
Keywords: Concrete, Freezing and Thawing, NDT Methods, Scaling 
1 Introduction 
In countries with a continental climate the freezing of water in concrete pores may be the cause for 
severe damage of concrete. Most of the freeze-thaw (F-T) accelerated tests measure the scaling of 
concrete by weighting. This procedure is straightforward and easy to perform, but includes some 
drawbacks, the test must be stopped to perform the weight measurement and the deterioration is 
detected when there is an appreciate scaling. This paper proposes the use of NDTs to perform 
continuous monitoring of the damage, without stopping the test, and to detect before the material 
failure. The complementary procedures are: the use of strain gauges, placed on different areas of 
the specimen, and the evaluation of the ultrasonic pulse velocity (UPV). Both procedures were 
performed with specimens under F-T accelerated testing (CEN/TS 12390-9 [1]) with two types of 
concrete: one susceptible to F-T damage and the other does not.  
2 Experimental programme 
2.1 Materials 
Two different concrete mixes were tested, combining two cement contents, two w/c ratios and the 
use or not of air-entrained admixture. Tab. 1 shows the concrete mixes. 
fib Symposium PRAGUE 2011 
Session 2A-3: Concrete Technology 
 
 342 
Tab. 1 Mix proportions (kg/m3) and concrete properties 
Mix Proportions 
Air Entrained Admixture 
Concrete (AEAC) 
Non Air Entrained 
Admixture Concrete 
(NAEAC) 
Cement CEM I 42.5 R (kg/m
3
) 450 360 
Water (l/m
3
) 180 162 
w/c ratio 0.40 0.45 
Fine Aggregate (kg/m
3
) 640.9 710.2 
Coarse Aggregate (kg/m
3
) 1159.1 1129.8 
Superplasticizer (kg/m
3
) 1.80 1.08 
Air-Entraining Admixture (kg/m
3
) 0.45 - 
Properties of Concrete   
Slump (cm) 8.0 7.5 
Air Content (%) 7.5 2.6 
Compressive Strength – 28d (MPa) 32.4 28.5 
 
2.2 Test procedures and methods 
The concrete specimens were half of a cube with a surface area of 150 x 150 mm
2
 and thickness of 
70 mm. Five specimens for each type of concrete were tested according to freeze-thaw standard 
CEN/TS 12390-9 [1]. They were inserted in a climatic chamber and subjected to 28 freeze-thaw 
cycles (FTCs) according to the temperature versus time diagram shown in Fig. 1a. 
 The test was performed with standard de-icing agent solution (97% of distilled water and 3% 
of NaCl). The surface deterioration was measured by weighting after 4, 6, 14 and 28 FTC.  
2.3 Non-destructive test measurements  
The superficial strain of the prism concrete samples was measured using two commercial strain 
gages by specimen, which were glued on the middle and upper part of the lateral surface of the 
specimens as shown in Fig. 1b (H1= 30 mm and H2= 55 mm).  
A double zero crossing algorithm [2] was used to measure UPV. For each concrete specimen 
two longitudinal wave transducers (500 kHz) were glued directly to the surface of the concrete 
prisms. The position of the transducers is shown in Fig. 1c.  
 
a)  
 
 
-30
-20
-10
0
10
20
30
0 1 2 3 4 5 6 7 8 9 10 11 12
T
e
m
p
e
ra
tu
re
 (
ºC
) 
Time (h)
 
b) 
     
c)  
 
 
 
 
 
 
 
Fig. 1 a) Temperature for one FTC. Sensors used for NTD measurements in concrete prisms 
subjected to FTC: b) Strain gauges, c) Ultrasonic transducers 
Test surface 
H2 
H1 
        Test surface 
 3 Experimental results and analysis
The results of scaling are shown in 
cumulative scaling of 1.5 kg/m
AEAC specimens reached only 0.10 kg/m
surfaces in contact with the de
testing, after 14 and 28 FTC
exposure of coarse aggregate. 
 
a)
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
0 5 10
AEAC
NAEAC
1,5 kg/m2
S
c
a
li
n
g
 (
k
g
/m
2
)
Number of Freeze-thaw Cycles
0,05
0,88
0,040,10
0,01
Non Air-entrained 
admixture concrete
Fig. 2 Freeze-thaw test. a) Cumulative scaling. Photographs of test surface of concrete slabs during the FTC
b) AEAC before the test, c) AEAC after 
Fig. 3a shows the strain gages measures. NAEAC shows a residual strain of 
AEAC a value of 65 µm/m, both 
the residual strain in NAEAC specimens 
placed at the upper part (H2) showed lower deterioration, which indicates 
moves away from the immersed
The UPV was measured on each specimen under thawing (20ºC) and freezing (
conditions. Fig. 3b shows the UPV measures during F
progressive deterioration of concrete leads to a lower UPV, as figure shows. Under freezing 
conditions the ice in the micro
indicates a progressive deterioration of the concrete. 
 
a)
-400
-200
0
200
400
600
800
1000
1200
0 4 8 12
NAEAC (Middle)
NAEAC (Up)
AEAC (Middle)
AEAC (Up)
S
tr
a
in
 (
µµ µµ
m
/m
)
Number of Freeze-thaw Cycles
Air-entrained Admixture 
Concrete (Up)
Non Air-entrained Admixture 
Concrete (Middle)
Fig. 3 Strains measurements a) Strains of concrete samples duri
of freezing (
fib Symposium PRAGUE 2011
Session 2A-3: Concrete Technology
 
Fig. 2a. The NAEAC specimens failed before 28 
2
 on the 17th FTC, and 3.23 kg/m
2
after 28 cycles
2
 of cumulative scaling after 28 cycles.
-icing agent solution of some specimens of both concretes before 
, are shown in Fig. 2b-d. Salt scaling is often 
 
15 20 25 30
3,23
0,10
Air-entrained 
admixture concrete
(AEAC)
(NAEAC)
 
b)  c)
d)  e)
28 FTC, d) NAEAC before the test, e) NAEAC after 
after 28 FTC, measured with the strain gage at H
shows the progressive damage [3-
a gradient
 face.  
-T testing. Under thawing 
-cracks increases the UPV, and the positive slope of the curve 
 
16 20 24 28
Air-entrained Admixture 
Concrete (Middle)
Non Air-entrained 
Admixture Concrete (Up)
 b) 
4,1
4,2
4,3
4,4
4,5
4,6
4,7
4,8
4,9
0 5 10 15
U
lt
ra
s
o
n
ic
 P
u
ls
e
 V
e
lo
c
it
y
 (
k
m
/s
)
Number of Freeze-thaw Cycles
Air-entrained Admixture 
Concrete (AEAC)
Non Air-entrained Admixture 
Concrete (NAEAC)
Máx. Temp. (Thawing)
ng 28 FTCs, b) UPV during FTC
min. temp) and at the end of thawing (max. temp).
 
 
 
343
FTC, with a 
. In contrast, the 
 The concrete test 
observed with the 
 
 
: 
28 FTC. 
1150 µm/m and 
1. The growth of 
4]. The strain gages 
 decreasing as it 
-20ºC) 
conditions the 
20 25 30
Min. Temp. (Freezing)
 
s. At the end 
 
fib Symposium PRAGUE 2011 
Session 2A-3: Concrete Technology 
 
 344 
4 Conclusions 
The damage caused by the freeze-thaw cycles in the AEAC prisms was negligible compared with 
the deterioration of the NAEAC specimens, as it was hoped. This result was confirmed by the 
scaling test and by the continuously measurement of strain and VPU.  
Strain as a measurement of length changes is a good indicator of freeze-thaw concrete 
superficial deterioration. Commercial strain gages may replace the conventional scaling measures. 
 The measured differences of UPV of concretes specimens before and after 28 FTCs were 
very small. That means that 28 FTCs according to the CENT/TS 12390-9 test, do not lead to 
considerable internal damage of tested concretes as have been reported in studies that use a high 
number of rapid FTCs like the ASTM C666/C666M standard.   
The authors gratefully acknowledge the financial support for the research provided by the Spanish 
Ministerio de Ciencia e Innovación under grants BIA-2008-03523 and MFOM-01/07. Héctor L. 
Romero also gratefully acknowledges the grant supplied by Fundación Agustín de Betancourt. 
References 
[1] CEN/TS 12390-9 EX. Testing Hardened Concrete. Part 9: Freeze-Thaw resistance. Scaling. 
CEN. Bruxelles. 2006. 
[2] Hernández MG, Anaya JJ, Sanchez T, Segura I. Porosity estimation of aged mortar using a 
micromechanical model. Ultrasonics 2006 12/22;44 (Supplement 1):e1007-11. 
[3] Bishnoi S, Uomoto T. Strain–temperature hysteresis in concrete under cyclic freeze–thaw 
conditions. Cement and Concrete Composites 2008 5;30(5):374-80. 
[4] Penttala V. Freezing-induced strains and pressures in wet porous materials and especially in 
concrete mortar. Advanced Cement Based Materials 1998;7:8-19. 
 
Hector L. Romero, C.Eng. 
 Universidad Politécnica Madrid 
 E.T.S. de Ingenieros de Caminos 
 Dept. de Ingeniería Civil: Construcción 
 c/ Profesor Aranguren s/n 
 28040 Madrid, Spain 
 +34 913 366 723 
☺ hector.romero@caminos.upm.es 
 
Dr. Maria J. Casati, Ph.D., C.Eng. 
 Universidad Politécnica Madrid 
 E.U.I.T. Aeronáutica 
 Dept. Vehículos Aeroespaciales 
 Pl. Cardenal Cisneros s/n 
 28040 Madrid, Spain 
 +34 913 367 503 
☺ mariajesus.casati@upm.es 
Prof. Jaime C. Gálvez, Ph.D., C.Eng. 
 Universidad Politécnica Madrid 
 E.T.S. de Ingenieros de Caminos 
 Dept. de Ingeniería Civil: Construcción 
 c/ Profesor Aranguren s/n 
 28040 Madrid, Spain 
 +34 913 365 350 
☺ Jaime.galvez@upm.es 
 
 
 


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NDT for concrete under accelerated freeze/thaw tests and surface scaling

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