Surface characterization methods for quality control of repair

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(1)Coopération scientifique Québec / Wallonie-Bruxelles. SURFACE CHARACTERIZATION METHODS FOR QUALITY CONTROL OF REPAIRS. A. Garbacz. Université de Technologie de Varsovie, Pologne. T. Piotrowski. Université de Technologie de Varsovie, Pologne. L. Courard. Université de Liège, Belgique. B. Bissonnette. Université Laval, Canada.

(2) REPAIR EFFICIENCY EVALUATION. • bond strength &. • bond quality … should be evaluated. 2.

(3) FACTORS AFFECTING BOND BETWEEN CONCRETE SUBSTRATE AND REPAIR MATERIAL Factors 1. Importance 2. 3. Substrate characteristics Substrate properties Microcracking Laitance Roughness Cleanliness. X X X X X. Overlay characteristics & application technique Pre-wetting Bonding agents. X X. Overlay properties Placement. X X. Compaction. X. Curing. X. Environmental conditions Time. X. Early traffic. X. Fatigue. X. Environment. X. 3.

(4) PREPARATION TECHNIQUES. (SILFWERBRAND, 2004). Removal method. Principle behaviour. Depth action?. Advantages. Disadvantages. Sandblasting & shotblasting. Blasting with sand or steel balls. No. No microcracking, no dust. Not selective. Flame-cleaning. Thermal lance. No. Effective against pollutions and painting. The reinforcement may be damaged, smoke and gas development, not selective. Milling (scarifying). Longitudinal tracks are introduced by rotating metal lamellas. Yes. Good bond if followed by water flushing. Not selective. Pneumatic (jack) hammers, hand-held or boom-mounted. Compressed-air-operated chipping. Yes. Simple use, large ones are effective. Damages reinforcement and concrete surface, poor working environment, not selective. Grinding. Grinding with rotating lamella. No. Removes uneven parts. Dust development, not selective. Explosive blasting. Controlled blasting using small, densely spaced blasting charges. Yes. Effective for large removal volumes. Difficult to limit to solely damaged concrete, not selective. Water-jetting (hydrodemolition). High pressure water jet from a unit with a movable nozzle. Yes. Effective, selective, does not damage reinforcement or concrete, improved working environment. Water handling, removal in frost degrees, costs for establishment. 4.

(5) METHODS OF SURFACE ROUGHNESS CHARACTERIZATION ANALYZED IN THE PROJECT • Concrete surface profile (CSP), in accordance with ICRI Guideline No. 310.2R-2013. • Sand patch test, in accordance with ASTM E965 (similar to EN 13036-1:2010) and EN 1766. • Mechanical profilometry. • Laser technique. • Interferometric profilometry.. 5.

(6) CONCRETE SLABS TESTED IN THE PROJECTS Group A: Grinding (GR), sandblasting (SB), shotblasting (SHB20, SHB35 and SHB45, with treatment times of 20, 35, and 45 seconds, respectively), hand milling (HMIL) and mechanical milling (MMIL); untreated concrete samples (NT) were also tested as a control; Group B: Polishing (PL), dry sandblasting (SB-D), jack hammering (JH) and water jetting at 250 MPa pressure (HD); Group C: Gentle surface preparation methods were used to obtain profiles of similar amplitude and low-level microcracking: brushing (NT), wet sandblasting (SB-W), scarifying (SC) and water jetting at 12 MPa pressure (LC).. 6.

(7) VISUAL OBSERVATION (1) grinding. shotblasting. sandblasting. milling. 7.

(8) VISUAL OBSERVATION (2) CSP1. CSP4. CSP7. CSP2. CSP5. CSP8. Surface preparation methods Detergent scrubbing. 1. Low-pressure water cleaning. 1. CSP3. CSP6. CSP9. CSP. Acid etching. 1–3. Grinding. 1–3. Abrasive blasting (sand). 2–5. Steel shotblasting. 3–8. Scarifying. 4–9. Needle scaling. 5–8. Water jetting. 6–9. Scabbling. 7–9. Flame blasting. 8–9. Milling/rotomilling. 9 8.

(9) SAND PATCH TEST. ASTM E965 (very similar to EN 13036-1). The surface roughness is characterized using glass or sand particles by the mean texture depth (MTD) :. 4V MTD = [ mm] 2 πD. EN 1766 The surface roughness is characterized using sand particles by the surface roughness index (SRI). SRI =. V ⋅ 1272 2 D. V = 25 mL. V = volume of granular material [mm3]; D = diameter of circle covered by granular material [mm]. 9.

(10) MECHANICAL PROFILOMETER L.Courard, M. Nélis. a high-precision extensometer is moved over the entire. surface to obtain a 3D map (with x, y and z coordinates) from which morphological parameters are computed. stylus type. real profile. profile registered. 10.

(11) LASER PROFILOMETER the superficial elevation (distance from the laser beam source to the object) of each point is calculated on the basis of the laser beam transit time.. 11.

(12) INTERFEROMETRIC PROFILOMETRY based on observation and analysis of the shadow produced by the superficial roughness of the surface (moiré fringe pattern principle). Matemathical transformation. 12.

(13) GEOMETRICAL PARAMETERS OF SURFACE STRUCTURE ACC. PN-EN ISO 4287 (1): profile filtration. Waviness. mean frequencies amplitude Wm is 1001000 times the depth of holes Wt. Rt. Roughness. roughness: Rm = (5...100)·Rt. waviness: Wm = (100...1000)·Wt Wm Wt. Rm. high frequencies gap between grooves (amplitude) Rm is 5-100 times the depth Rt. 13.

(14) GEOMETRICAL PARAMETERS OF SURFACE STRUCTURE ACC. PN-EN ISO 4287 (2): Symbol. Parameters. Sy. Definition. m-. line whose height (mean value) is determined by mx. Xp. Xm. Xt. mean value and line. max peak height. max valley depth. max height. minimal sum square deviation of the profile defined as Sk. follows: X = min∑ y 2 ( x). Xa. ’. Xq. arithmetic mean deviation. Root mean square deviation. Definition. skewness of. a measure of asymmetry of profile deviations about the. surface height. mean line, as follows: S k =. distribution. distance between the highest point of the profile and the mean line. Sm. distance between the lowest point of the profile and. mean period of profile roughness. the mean line maximum distance between the lowest and the highest point of the profile and it’s equal Xt = max (Xp + Xm) mean departure of the profile from the reference mean. Xa. Parameters. bol. line as follows:. Xa =. np. tp. bearing length. 1 1 R q3 n. n. ∑Y i =1. 3 i. mean value of mean line including consecutively a peak and a valley Smi, as follows: S m =. 1 n. n. ∑S i =1. mi. sum of partial lengths ni corresponding to the profile cut by a line parallel to the mean one for a given cutting level. bearing length. ratio between bearing length and cut-off length, given as. ratio. a percentage (%): tp = np/l.. Sm1. Sm2. Sm3. Smi. mean line. n. 1 l 1 y( x) dx , approximated by X a ' ≈ ∑ yi l ∫0 n i =1 l. statistical nature parameter it is defined in the limits of the cut-off length X q =. 1 l 2 y (x)dx l ∫0. n1. n2. ni. maximum line cutting level mean line minimum line. 14.

(15) GEOMETRICAL PARAMETERS OF SURFACE STRUCTURE ACC. PN-EN ISO 4287 (3): Bearing curve (Abbot’s curve) Sym -bol. Parameters. CR. relative height of the peaks. CF. depth of the profile. CL. relative depth of the holes. Definition gives an idea of significance of the volume of very high peaks above the reference line excluding high peaks and deep holes gives information on surface flatness; a lower value of CF means an important surface flatness gives an idea of the significance of the volume of voids under the reference line. 15.

(16) MECHANICAL (P) VS. LASER (S) PROFILOMETRY (1) 400. Was, Wap [µm]. Wap [µm]. 500. r=0.94. 300 200 100 0 100. 200. 300. 400. 500. 600. r=0.97. 450 300 150. r= 0.95. 0 100. 600. Was [µm]. 120. 140. 160. 180. 200. SRI [mm] Wts vs Wtp. r = 0.76. Wvs vs Wvp. 2000 1500. r = 0.54 1000 500. MMIL. 0. 1000 Crp, Cfp, Clp [µ µ m]. Wtp, Wvp [µm]. 2500. r = 0.96. 800. r = 0.97. 600 Crs vs Crp. 400. Cfs vs Cfp. MMIL. 200. Cls vs Clp. 0. 0. 1000. 2000. 3000. Wts, Wvs [µm]. 4000. 0. 1000. 2000. 3000. 4000. Crs, Cfs, Cls [µ µ m]. 16.

(17) MECHANICAL (P) VS. LASER (S) PROFILOMETRY (2) 140. 30 Laser. Laser. 120. 25. Mechanical. Ra, µm. Rt, µm. 100 80 60. Mechanical. 20 15 10. 40. 5. 20 0. 0. GR. SB. SHB35 SHB45 surface treatment. HM. MM. GR. SB. SHB35 SHB45 HM surface treatment. MM. surface treatment technique does not have much influence on microroughness (high-frequency waves). The waviness parameters actually need to be determined in order to assess surface roughness prior to repair 17.

(18) SURFACE ROUGHNESS CHARACTERIZATION WITH THE MICROSCOPIC OBSERVATION METHOD S. 120. o. 300 mm. 50 mm. 20 mm. m easurem ent rectangle. 300 mm. So 2,0. 600. Rs. RS = S/SO. Was, Wap [µm]. r = 0,97. 1,9 1,8 1,7. surface roughness is related to the energy being dissipated during material decohesion. 1,6. r = 0.81 450 300 r = 0.78. 150 0. 0,0. 0,5. 1,0. SRI [mm]. 1,5. 2,0. 1,6. 1,7. 1,8. 1,9. 2,0. RS. 18.

(19) INTERFEROMETRY VS CSP 0,6. Ma (mm). 0,5 0,4 0,3 0,2 0,1 0,0 1. 2. 3. 4. 5. 6. 7. 8. 9. CSP number. The actual CSP plates are rather narrow with respect to the spectrum of CSPs obtained with actual surface preparation techniques.. 19.

(20) SUMMARY Characterization of surface roughness is an important aspect in assessing a concrete substrate prior to repair. Various techniques have recently been available for CSP characterization. The waviness parameters actually need to be determined in order to assess surface roughness prior to repair. Among the techniques available today, the best suited method for field assessment appears to be the CSP developed by ICRI.. 20.

(21) ADHESION VS. SUBSTRATE QUALITY (2). C20/25. 21.

(22) C20/25. przyczepność, MPa. 2.5. w.sczepna. 2.0. 3. 1.5 1.0 0.5 r = 0.82 0.0 0. 100 200 300 400 500. W a [µ m ]. p rz y c z e p n o ś ć , M P a. ADHESION VS. SUBSTRATE QUALITY (2) 4 C20/25. C30/35. C40/50. C50/60. 3 2 1 0 0. 2. 4. 6. wskaźnik chropowatości, mm. 22.

(23) ADHESION VS. SUBSTRATE QUALITY (3) 3,5. 1,96. 0,37. 0,78. 0,94. 0,69 0,96. 1,6. 1,51 1,42. 1,94 0,92. 1,0. 0,76 0,83. 0,93. 1,5. RM. B. 1,38. 1,68. 2,13 1,93. 1,62. 1,98 1,82. 2,68 1,92. 2,0. 2,08. pull-off strength [MPa]. 3,0 2,5. without BC - interface failure without BC - cohesive failure with BC - cohesive failure. 0,5 0,0 NT. GR. SB. SHB20 SHB35 SHB45. HMIL. MMIL. treatment type. 23.

(24) Density of cracks [mm/mm2]. MICROCRACKING EVALUATION (1) Surface area. 0,2. Internal area 0,15. 0,1. 0,05. 0 2. 5. 7. 9. 12. 14. Specimen number. M.Glinicki, A.Litorowicz, 2005. 24.

(25) MICROCRACKING EVALUATION (1). A3. C25/B. 25 LC. HD. JH. SB-D. SC. SB-W. type A1 BR. 0 HD. 0. JH. 1. 1 SB-D. 2. 50. 0 PL. 3. 2. 25 0. 4. LC. fh [MPa]. 3. PL. fh [MPa]. C30/A 4. 50. 75. SC. A2. 75. SB-W. A1. 100. NT. 15 mm. C25/B. C30/A. 100. type of failure [%]. type of failure [%]. fhs. 25.

(26) PULL OFF IS THE MOST COMMON TEST 0,5 1 1,5 2 2,5 3 ponad. 4,5. NDT!. above. 3,5 2,5 1,5 0,5 67,5. Impact-echo Ultrasonic GPR. 45,0. 22,5. 0,0 szerokość,. m. 0,0. 28,6. 57,3. 86,0. 143,0 114,5. długość,. m. 26.

(27) REPAIR SYSTEM AS AN OBJECT OF NDT TESTING. DEFECT TYPES • Adhesion type (at the interface zone of RM-CS system): non-zero volume debonding (delamination), zero-volume debonding, weak adhesion areas • Cohesion type (in repair material or/and concrete substrate): porosity, cracks, honeycombing, unhardened resin (PC). 27.

(28) SELECTION OF NDT METHOD • Defect size & depth • Repair material thickness L>λ. h min > 0,5 λ h max < 4 λ. • Repair material type (R coeff.) • Substrate quality. Ar Z2 - Z1 R = = Ai Z 2 + Z1. 28.

(29) RESULTS pull-off strength, MPa. 2.5 2.0 1.5 1.0 0.5. BC. no BC. 0.0 0. 100. 200. 300. 400. 500. Wa, µ m pull-off strength, MPa. 2.5 2.0 1.5 1.0 0.5. BC. no BC. 0.0 0. 500 1000 1500 2000 2500. Wt, µ m. 29.

(30) CONCRETE SUBSTRATE QUALITY (2) Group A Concrete Surface preparation. Group B. C30/37, C40/50, C50/60 no treatment NT wet sandblasing SB-W scaryfication SC water jetting LC. polishing PL dry sandblasting SB-D jack hammering JH hydrodemolition HD. SRI [mm]. Total length of microcracks [mm] Bond strength (pull-off) [MPa]. acc. EN 1542 30.

(31) EFFECT OF CONCRETE SUBSTRATE PREPARATION (LAB) polishing. a). sandblasting. b) 0.06. f bottom. relative amplitude. relative amplitude. 0.06. f interface. 0.04. 0.02. 0. f bottom. 0.02. 0 0. 20. 40. 60. 80. 100. 120. 0. 20. 40. frequency, kHz. c). 60. 80. 100. 120. 100. 120. frequency, kHz. d). scabbling. hydrodemolition. 0.06. 0.06. f bottom. relative amplitude. relative amplitude. f interface. 0.04. f interface. 0.04. ?. 0.02. 0. f bottom 0.04. f interface. ?. 0.02. 0. 0. 20. 40. 60. 80. frequency, kHz. 100. 120. 0. 20. 40. 60. 80. frequency, kHz. 31.

(32) EFFECT OF CONCRETE SUBSTRATE PREPARATION (FEM) S. S. h. Sandblasting. S [mm]. h [mm]. SB. 4. 2. HD. 8. 8. h. Hydrodemolition. 32.

(33) LAB vs. FEM S. S. h. SB:. h. 0.007. 0.007. f bottom 0.02. magnitude. f interface. 0.04. magnitude. relative amplitude. 0.06. 0.005. 0.003. 0.005. 0.003. 0 0. 20. 40. 60. 80. 100. 0.001. 120. 0.001 0. 20. frequency, kHz. HD:. 40. 60. 80. 100 120. 0. 0.007. 0.02. 0.005. 0.003. 0.001. 0 0. 20. 40. 60. 80. frequency, kHz. 100. 120. 60. 80. 100 120. 0.007. magnitude. magnitude. relative amplitude. f iterface. 0.04. 40. frequency, kHz. 0.06. f bottom. 20. frequency, kHz. 0.005. 0.003. 0.001 0. 20. 40. 60. 80. frequency, kHz. 100 120. 0. 20. 40. 60. 80. 100 120. frequency, kHz. 33.

(34) SUMMARY • For the both IE and ultrasonic methods, the roughness and microcracking of the concrete substrate do not affect significantly the P-wave propagation through the repair system if the bond quality is sufficient absence of large voids at the interface. 34.

(35) SUMMARY • Parameters describing roughness and microcracking of concrete substrate can be considered as important variables for improvement of reliability of the bond strength evaluation, using more advanced signal analysis of stress waves (e.g. wavelet approach). 35.

(36) CONCRETE very good construction material. 4th successful. Repair of concrete Never ending story. 36.

(37) ACKOWLEDGMENTS • Concrete Research Council de l’American Concrete Institute (ACI) • Conseil de Recherche en Sciences Naturelles et en Génie du Canada (CRSNG) • Fonds de Recherche Québécois sur la Nature et les Technologies (FRQNT) • U.S. Bureau of Reclamation (USBR) • Chaire CRSNG sur la Réparation durable et l’entretien optimisé des infrastructures en béton à l’Université Laval (BASF, Euclid, Holcim, Hydro-Québec, Kerneos, King Packaged Materials, Lafarge, Ministère des Transports de Québec, Ville de Montréal, Ville de Québec, W.R. Grace & Co.) • Programmes de coopération scientifiques des gouvernements polonais, québécois et de Wallonie-Bruxelles 37.

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(39) •January 4, 1826 - the Preparatory School for the Institute of Technology, •June 8, 1898 - Tsar Nikolaus II Institute of Technology, •November 15, 1915 - Warsaw University of Technology (with Polish as the language of instruction).. 39.

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