Nondestructive evaluation of internal sulphate f p attack in - - PowerPoint PPT Presentation

Non‐destructive evaluation of internal sulphate f p attack in cement‐based materials applying non‐ linear ultrasonic techniques linear ultrasonic techniques

José Marcos Ortega, Marina Miró, Pedro Poveda, Antonio José Tenza‐Abril, Jaime Ramis Miguel Ángel Climent Jaime Ramis, Miguel Ángel Climent

Departamento de Ingeniería Civil, Universidad de Alicante (Spain) DFISTS, Universidad de Alicante (Spain)

Outline

1 Introduction

• 1. Introduction
• 2. Materials and methods
• 3. Results and discussion
• 4. Conclusions
• 4. Conclusions

2

Introduction

Introduction

Sulphate attack

 It is one of the most harmful aggressive attack to  It is one of the most harmful aggressive attack to

which cement‐based materials can be exposed

 Complex mechanism → Involves different chemical

reactions between components of cement paste microstructure and sulphate ions microstructure and sulphate ions.

 Expansive products are formed:

 Volumetric strains → Microcracking and loss of pore

refinement

 Loss of strength and durability in the cement‐based

materials

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Introduction

Non‐destructive techniques

 Their application for characterizing the  Their application for characterizing the

microstructure and properties of cement‐based materials has become an important research field p

 Useful for following the development of deleterious

d d d i th tt k f i processes produced during the attack of aggressive substances to these cement‐based materials.

 Non‐linear ultrasonic (NLU) → Detecting cracks due

to steel corrosion in reinforced concrete structures:

 DOI: 10.1186/s40069‐020‐00432‐x  DOI: 10 3390/MA12050813

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 DOI: 10.3390/MA12050813

Introduction

Objetives

d h ibili f i h i To study the possibility of using NLU techniques Non‐destructive evaluation Initial stages of internal sulphate attack in cement based materials cement‐based materials (until 100 hardening days)

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Materials and methods

Materials and methods

S l ti Samples preparation

 Materials (cement pastes):  Materials (cement pastes):

 Reference specimens → CEM I 42,5 R (100%)  Sulphate specimens → CEM I 42 5 R (90 8%) + gypsum  Sulphate specimens → CEM I 42,5 R (90.8%) + gypsum

(9.2%) → To reach in the mixture a SO3 context of 7% in mass according to ASTM Standard C452‐02 mass according to ASTM Standard C452 02

 Water to cement ratio = 0.5  Seng → UNE EN 196 3  Seng → UNE‐EN 196‐3

 Prismatic samples:

 25 mm x 25 mm x 285 mm.

St i ti l b t diti

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 Storage in optimum laboratory condition

Materials and Methods

Experimental techniques

M i t i i t

 Mercury intrusion porosimetry

h h d

 Length change due to expansion  Non‐linear ultrasonic technique  Linear ultrasonic pulse velocity

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Materials and methods

M i i i Mercury intrusion porosimetry

 Poremaster‐60 GT porosimeter  Total porosity  Pore size distributions  Percentage of Hg retained at the end of the test  Pieces taken from prismatic specimens

p p

Length change due to expansion

 ASTM Standard C452‐02

i l i l l i Linear ultrasonic pulse velocity

 Standard UNE‐EN 12504‐4

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 Proceq Pundit Lab equipment

Materials and methods

N li l i h i Non‐linear ultrasonic technique

 Two transducers → Simultaneously supply two pure

tones (f0 = 20 kHz and f1 = 200 kHz)

 High‐frequency probe signal at an amplitude of 5 V  Low‐frequency pump and acquisition of the

frequency modulated signal → 16‐bit ADC resolution I/O d i NI USB 6361 ( li f 2 MH ) I/O device NI‐USB 6361 (sampling frequency 2 MHz)

 Pump wave signal → Amplifier FS WMA‐100 and

then transmitted through a Langevin transducer

 Input voltage → 140 V  Transducers IDK09 → Emitting and receiving the

high‐frequency signal

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 Parameter DIFA was studied in this work

Results and discussion

Results and discussion

50 Reference S l h t

100

1 d 100d 100d 28d 28d

>0.1 mm 10 µm-0.1 mm 1-10 µm 100 nm-1 µm 10-100 nm <10 nm

1d

40 45

ty, %

Sulphate

80

me, %

30 35

tal porosit

40 60

• n volum

25 30

Tot

20

Intrusio

20 40 60 80 100 20

Hardening age, days

Sulphate Reference

 Lowest porosity and highest pore refinemement → Reference  Progressive pore refinement with age → Sulphate specimens

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• g ess e po e e

e e t t age → Su p ate spec e s

 Combined effects of clinker hydration and initial sulphate attack

Results and discussion

45 50 0.20 Reference Sulphate 40

ned, %

0.15

• n, %

30 35

Hg retain

0 05 0.10

Expansio

25

H

Reference Sulphate 0 00 0.05

E

20 40 60 80 100 20

Hardening age, days

20 40 60 80 100 0.00

Hardening age, days

 Hg retained → Overall in keeping with pore size distribuons  Expansion for pastes subject to internal sulphate attack

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pa s o

• pastes subject to

te a su p ate attac

 Expansion would reveal possible microcracking development

Results and discussion

80 4000 75 80 Reference Sulphate 3800 4000

ity, m/s

70 75

IFA, dB

3600

se veloci

65

DI

3200 3400

sonic pul

20 40 60 80 100 60 20 40 60 80 100 3000 3200

Ultras

Reference Sulphate

DIFA → S t d ll t d l li f l h t t

20 40 60 80 100

Hardening age, days

20 40 60 80 100

Hardening age, days

 DIFA → System gradually turned less linear for sulphate pastes  UPV → Coincided with PIM and not reveal effects of aack

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 NLU technique could be useful for providing information about

the deleterious processes due to internal sulphate attack.

Conclusions

Conclusions

Conclusions

 Reference pastes showed an important pore refinement  Reference pastes showed an important pore refinement

at 28 hardening days → Microstructure development due to the hydration of clinker y

 Pore size distribution of cements pastes exposed to

internal sulphate attack gradually became more refined internal sulphate attack gradually became more refined, but lower refinement compared to reference pastes → Simultaneous development of clinker hydration and Simultaneous development of clinker hydration and sulphate attack (silting of pores and later microcracking)

 Continuous expansion for pastes subject to internal

sulphate attack → Possible presence of pores already silted in which a possible formation of microcracks due

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silted in which a possible formation of microcracks due to expansion could be produced.

Conclusions

Conclusions

 The tendencies observed for the NLU parameter DIFA

p were overall in keeping with the results of the length change due to expansion.

 Linear ultrasonic pulse velocity → Progressive reduction

• f oids

ith a e in the st died samples → No effe ts of

• f voids with age in the studied samples → No effects of

sulphate attack in this parameter.

 In view of these preliminary results → NLU technique

could be useful for providing information about the could be useful for providing information about the deleterious processes due to internal sulphate attack in cement‐based materials → Further research would

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be needed for confirming this.

A k l d t Acknowledgments

Project GV/2019/070 Project GV/2019/070 Project BIA2016‐80982‐R Pre‐doctoral fellowship Pre doctoral fellowship FPU16/04078 Cementos Portland V ld i S A

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Valderrivas, S.A.

Non‐destructive evaluation of internal sulphate f p attack in cement‐based materials applying non‐ linear ultrasonic techniques linear ultrasonic techniques

José Marcos Ortega, Marina Miró, Pedro Poveda, Antonio José Tenza‐Abril, Jaime Ramis Miguel Ángel Climent Jaime Ramis, Miguel Ángel Climent

Departamento de Ingeniería Civil, Universidad de Alicante (Spain) DFISTS, Universidad de Alicante (Spain)