Surfology: new investigations techniques and approaches

November 29th_{, 2010}

Concrete Repair Science:

new trends

Cooperation between the University of Liege and the Politechnika Warsawska

November 29th_{, 2010}

Surfology: new investigations

techniques and approaches

A. Garbacz, Politechnika Warszawska L. Courard, Université de Liège

Surfology:

techniques and principles

1. Concrete Repair

Needs for knowledge

2. Surfology

Definitions

3. How to quantify surfology?

Roughness, thermodynamic equilibriums, water

4. Why is surfology needed?

Repairing concrete

Surfology:

needs for knowledge

Nowy swiat, Warsaw, 2009

Surfology:

32 18 16 12 4 3 14 incorrect design material w orkmanship diagnosis

w eather (during repair w orks)

unknow n others

60%

Surfology:

needs for knowledge

… the heterogeneity of the components in a composite repaired structure requires an understanding of the

interaction of the existing materials and the repair

materials …

(Vaysburd et al., 2004) The reliability and durability of a repaired concrete substrate and its remaining service life depends on the behavior of the repair material, which is controlled by the compatibility between the two materials making up the repair system.

(Czarnecki, 2004)

Surfology:

Surfology

Near-to-surface layer

Coating

scientific and technological approaches related to the design, the production and the application of surface layers to improve properties of the substrate, particularly resistance to corrosion

and abrasion and aesthetic properties as well *

(Burakowski T., Wierzchoń T. 1999. Surface engineering of metals. Principles. Equipment. Techn., CRC Press)

surface engineering covers: all phenomena involved with a

modification of near-to-surface layer and/or application of coating suitable for a given application

Surfology: definitions

Surface engineering in the case of concrete structures:

•to reach a desired durability of new structures,

•repair existing structures.

European Standards EN 1504

•improvement of near-to-surface layer quality by hydrophobic

treatment or impregnation,

•removal of deteriorated concrete and repair with fresh mortar,

•application of adhesive coating to improve barrier properties.

Surfology: definitions

Skin Bulk concrete

d

2 1

≈ with d : maximum size of aggregates

1 2 3 2 3 1 Surfology: definitions

SUBSTRATE •surface energy •roughness •porosity •capillary succion •saturation level •mechanical characteristics •interstitial water NEW LAYER •surface energy •binder setting •kinetics of contact •thermal dilatations •shrinkage •porosity, capillarity •mechanical characteristics ENVIRONMENT hydrothermal conditions of substrate and air

curing conditions

HUMAN FACTORS

Creation and stability of the interface

Surfology: definitions

Physico-chemical interactions

Thermodynamic approach

Chemical bonding

Specific adhesion _{Mechanical adhesion}

Adhesion

Condition 1 : spreading and wettability Condition 2 : physico-chemical interactions Condition 3 : mechanical interlocking

Geometric profile Real profile Effective profile

Surfology: definitions

Surfology

Reference ICRI plates and comparison with roughness on site Surfology: roughness

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 H SC S N P C30/37 C40/50 C50/60

Surface Rough Index

SRI = 4V/πD² H = water-jetting SC = scabbling S = sandblasting P = polishing Out of range Surfology: roughness

6 µm 1.5 mm

Technical characteristics

-system capacity: 1000 by 1000mm - surface of measurement : 30 by 30mm - shape of the stylus: spherical

- diameter of the stylus: 6µm and 1.5mm - step of measurement: 300µm

Surfology: roughness

Atos I 3D Digitizer

Fringe patterns Measuring area:

120×100 - 1000×800 mm2

Spatial resolution: 0,04-1 mm

Equipments to measure surface texture

Mechanical profiling

Measuring area : 200x200 mm Shape of the stylus: truncated cone

Diameter of the stylus: 1 mm Path of measurement: 1 mm

(Schwall, Courard, Belair, Perez, Bissonnette and Piotrowski 2007)

M a th e m a ti ca l tr e a tm e n t Surfology:

Deformation of parallel and periodic fringes (level line)

Surfology: roughness

Definition of description parameters

Filtration process: standard

• Meso-waviness • Waviness • Micro-roughness • Nano-roughness
Filtration process: 0.800 mm Surfology: roughness

Total profile Waviness _Roughness

Automatic calculation of surface roughness parameters by signal treatment (D. Schwall)

RugoDS

Surfology: roughness

Scarification Water jetting

Surfology: roughness

γ_SA = γ_SB + γ_AB . cos θ γ_SV = γ_SB + γ_BV . cos θ γ_AB SOLID (S) γ_SV γSL LIQUID (B) VAPOUR (V) γ_LV θ SOLID (S) LIQUID (A) LIQUID (B) θ γ_SBL γ_SA γ_B . cos θ_B - γ_A . cos θ_A < γ_AB γ_B . cos θ_B - γ_A . cos θ_A > γ_AB

Equilibrium : the difference between tensions of adhesion is inferior to interfacial tension

No equilibrium : liquid B will expulse liquid A

γ_S = γ_SA + γ_A . cos θ_A

γ_S = γ_SB + γ_B . cos θ_B

the liquid with the higher tension of adhesion will expulse the other one from the surface

Surfology:

Critical surface energy is the maximum

surface free energy of liquid that will spread on specific solid surface

Surface free energyγ_L 18.5 PolyTetraFluorEthylen (PTFE) 31 PolyEthylen (PE) 39 PolyVinyl Chloride (PVC) 43-44 Epoxy resin (EP)

42.5 Limestone 25.5 Cement paste Critical surface energy (mN/m) Substrate cosθ Surfology: thermodynamic properties

Surfology

• spreading on the surface, shear stress, viscosity

• penetration into the

capillaries of the superficial concrete • environmental conditions (temperature, relative humidity) conditions and kinetics of contact Fresh mortar Fresh mortar substrate substrate CC mortar PCC mortar polymer

(Ohama, 1989 - Ohama and Pareek,1993)

Surfology: adhesion

( θθθθ ) γ _LV 1+ cos = a _SL W_a = γ _LV(1+ cosθθθθ ) SL W SOLID (S) γγγγSV γγγγSL LIQUID (L) γγγγLV LIQUID (L) γγγγSL Surfology: effect of water

0 20 40 60 80 0 1 2 fc , fb , M P a w_agg, % fc (PM) fc (PC) fb (PM) fb (PC) w_agg [%] (f_cw_-f cdry)/fcdry [%] (f_bw_-f bdry)/fbdry [%] Polymer concrete 0.25 _{-36.8 -22.5} 0.50 _{-48.6 -58.7} 1.50 _{-84.2 -87.5} Polymer mortar 0.25 _{-42.2 -24.4} 0.50 _{-43.8 -61.2} 1.50 _{-69.9 -74.5} (W_AL - W_A) / W_A [%] for epoxy/concrete -72.6 % Surfology: effect of water

Surfology: effect of water 2.32 2.14 2.89 2.65 3.36 3.06 2.58 1.48 0.83 2.80 2.09 2.75 3.54 2.13 1.81 1.43 50 52 55 70 90 93 97 100

with wet slurry with dry slurry

Saturation level

Adhesion (N/mm²)

Surfology:

0 2 0 0 4 0 0 6 0 0 8 0 0 1 0 0 0 1 2 0 0 Wa Wp Wq Wv Wt W a v in e ss ( µ m ) Shot blasting 20s Shot blasting 35s Shot blasting 45s Surfology:

surface preparation techniques

0 500 1000 1500 2000 2500 With out Han d m illing Mec hani cal m illing Grin ding PL Shot bla stin g 20 s Shot bla stin g 35 s Shot bla stin g 45 s Sand blas ting P ro fi l (µ m ) Wa Wp Wq Wv Wt larger effect Medium effect Xp Xt Xv Surfology:

surface preparation techniques

0,0 0,5 1,0 1,5 2,0 2,5 3,0 0 1 2 3 4 5 6 A d h é re n c e ( M P a ) Ra (mm) POL NAT SCA-SAB HYD MPS7 MPS21 MPS14

(Vaysburd, Courard, Bissonnette and Bélair 2006)

Roughness?

Cohesion?

Surfology:

J14

J21

J21

Surfology:

roughness and adhesion

0 50 100 150 N T W J -1 2 4 S B S C R W J -2 5 0 J 0 7 + S B J 1 4 + S B J 2 1 + S B treatment type m ic ro c ra c k c u m u la ti v e l e n g th [m m ] agressiveness of treatment 0 10 20 30 N T W J -1 2 4 S B S C R W J -2 5 0 J 0 7 + S B J 1 4 + S B J 2 1 + S B treatment type d e p th o f m ic ro c ra c k in g [ m m ] agressiveness of treatment

NT – no treatment; WJ – water jetting – pressure 124 psi/250MPa; SB – sandblasting; SCR – scabbling; J+SB – jack

hammering of weight 7,14,21 kg + sandblasting

Application of polymer primer or polymer modified cement bonding agents usually improves the interface quality due to strengthening of concrete substrate

by gluing microcraks and lost concrete particles (Garbacz, Kostana and Courard 2006)

length (Li) of the cracks depth of microcracking

Surfology:

0.49 (57.1) 1.60 (24.4) MMIL 1.01 (40.6) 1.42 (12.7) HMIL 0.83 (25.3) 1.96 (32.7) SHB45 1.25 (28.8) 1.94 (11.3) SHB35 0.78 (39.7) 1.68 (18.5) SHB20 1.82 (32.4) 1.93 (11.4) SB 1.16 (50.9) 1.82 (15.9) GR 2.28 (17.1) 1.92 (23.4) NT

Repair mortar without bond coat Repair mortar with bond coat

Mean value [MPa] (coefficient of variation in %) Treatment type

Surfology:

roughness and adhesion

Surfology:

repair system as an object of NDT testing

non-zero volume & zero-volume disbonds pores cracks Repair materials not fully hardened resin concrete substrate

non-zero volume & zero-volume disbonds pores cracks Repair materials not fully hardened resin concrete substrate Selection of NDT method

• Defect size & depth

• Repair material thickness

• Repair material type (R coeff.)

Surfology:

influence on bond strength

b – relative influence on f_h prediction

ββββ (SRI) = 0.67 ββββ (fhs) = 0.63 β β β β (LA) = 0.12 β β β β (fck) = - 0.08 Group A Group B fhs [MPa] SRI [mm] > 1 < 1 < 0,8 < 0,6 < 0,4 < 0,2 fhs [MPa] SRI [mm] U(f_h)=1.0 for f_h ≥≥≥≥ 2.5 MPa

U(f_h)=0.5 for f_h = 1.5 MPa

U(f_h)=0.0 for f_h ≤≤≤≤ 0.5 MPa

U(f_h) – usability function

Surfology:

NDT testing with Impact-echo method

d d1 Time [µµµµs] A m p li tu d e f_d f_d1 Frequency [kHz] A m p li tu d e d p f c d ⋅ = 2 FFT G ro u p A 0 0,02 0,04 0,06 0 20 40 60 80 100 120 a m p li tu d a częstotliwość [kHz] 0 0,02 0,04 0,06 0 20 40 60 80 100 120 a m p li tu d a częstotliwość [kHz] C30-SB-D 1 11 21 30 40 50 60 69 79 89 99 108 118 f [kHz] C30-SB-D-1 C30-SB-D-2 C30-SB-D-3 C30-SB-D-4 C30-SB-D-5 C30-SB-D-6 C30-SB-D-7 C30-SB-D-8 C30-SB-D-9 C30-SB-D-10 C30-SB-D f_h = 2.04 MPa C30-JH f_h = 1.02 MPa C30-JH 1 11 21 30 40 50 60 69 79 89 99 108 118 f [kHz] Ab Ai Ab Ai R = 0.29 G ro u p B > 0,4 < 0,4 < 0,35 < 0,3 < 0,25 < 0,2 < 0,15 < 0,1 < 0,05 1 11 21 30 40 50 60 69 79 89 99 108 118 f [kHz] C50-LC-1 C50-LC-2 C50-LC-3 C50-LC-4 C50-LC-5 C50-LC-6 C50-LC-7 > 0,4 < 0,4 < 0,35 < 0,3 < 0,25 < 0,2 < 0,15 < 0,1 < 0,05 1 11 21 30 40 50 60 69 79 89 99 108 118 f [kHz] C50-SB-W-1 C50-SB-W-2 C50-SB-W-3 C50-SB-W-4 C50-SB-W-5 C50-SB-W-6 C50-SB-W-7 C50-LC: f_h= 0.00 MPa C50-SB-W: fh= 0.14 MPa

Surfology: wavelet approach 249 kHz 125 kHz approximation signal DWT

Discrete Wavelet Transform

details 62 kHz D1 D2 D3 ∆ ⋅ = a f f c a r = 0,88 0,0 1,0 2,0 3,0 0,0 1,0 2,0 3,0 fh [ M P a ] f_h,IE[MPa] R=0.88 Group A r = 0,87 0,0 1,0 2,0 3,0 0,0 1,0 2,0 3,0 fh [ M P a ] f_h,IE[MPa] Group B R=0.87 0.88 0.76 0.68 0.87 0.87 0.85 0.0 0.2 0.4 0.6 0.8 1.0 D2 and D3: MAD,RG,SD +SRI +SRI,fhs R e g res s io n c o e ff ic ien t ,R Group A Group B T.Piotrowski et al., 2010

Surfology:

FEM model of repair system (LS-Dyna)

 infinite plate; thickness 200 mm

 thickness of concrete: 100 ÷ 200 mm

 thickness of repair: 0, 20, 40, 60,

80,100 mm

 elasticity modulus:

• concrete: 38 GPa

• repair mortar: 10, 20, 30 GPa

 delamination size: 20 x 260 mm

with delamination without delamination

A.Garbacz, L.Kwaś_{niewski., 2006}

SB HD S h S h S [mm] h [mm] SB 4 2 HD 8 8

http://floconsdebonheur.wordpress.com/2008/08/21/le-king

Surfology, as a scientific concept including all surface properties of materials and their influence on adhesion, contributes to understand what will make the contact effective or not, and allow interactions of variable intensities between the materials at different scales of observation.

Thank you for your attention