In In-Pl Place St Stre rength Wi h Withou out Tes esting Co Cores es: The he Pul Pullou out T Test Nicholas J. Carino, PhD Consultant, Chagrin Falls, OH, USA 6 th International Seminar on Advances in Cement & Concrete Technology for Sustainable Development 1
Curren ent P t Practic tice f e for Acceptan tance ce Testing ng of of Conc oncre rete • Standardized testing of specimens made from concrete delivered to the project Standard consolidation Standard curing • Provides assurance that correct concrete was delivered • Indicates potential strength Does not account for actual consolidation and curing 2
Fut Futur ure P Perf rformanc nce-Bas ased ed Specif ifica icati tions • Measure in-place properties of concrete to ensure structure will perform as intended • Methods for estimating in-place strength Testing drilled cores High cost Rebound number method Requires correlation Probe penetration test testing for each concrete mixture Ultrasonic pulse velocity Pullout test Reliable estimates 3
Out Outline ne • Explain pullout test • Strength correlation and failure mechanism • Describe CAPO-Test • Case study • Summary 4
Pu Pullout T t Test est ASTM C C 900 00 Measure force to pullout an insert anchored in concrete. Cast-in-place (CIP): LOK-Test Post-installed (PI): CAPO-Test 5
CIP IP-Pullout Pullout T Test 25 mm Insert Insert 25 mm Formwork 6
CIP IP-Pullout Pullout T Test Insert Insert 55 mm Pullout Force Reaction Ring 7
Te st st CIP IP-Pullout Pullout T Insert Insert Pullout Force Reaction Ring 8
Pul Pullou out T Test COMA-meter Apply Pullout Load Conical Fragment 9
Esti timate Co e Concr crete S e Str tren ength 100 Compressive Strength, MPa 80 60 40 20 0 0 10 20 30 40 50 60 70 80 Pullout Load, kN 10
Correla elati tion T Testin ting ACI CI 228. 228.1R • Prepare cylinders (or cubes) for standard compressive strength testing • Prepare 200-mm cubes with inserts • Cure all specimens under same conditions 11
Correla elati tion T Testin ting • At ages of 1, 2, 3, 7, 14 and 28 days: Test 2 cylinders (or cubes) for 200 mm compressive strength Perform 8 pullout 200 mm tests (2 cubes) 12
Example o le of C Correlatio lation 35 Cylinder Strength, MPa 30 25 20 15 10 5 10 15 20 25 30 Pullout Force, kN http://www.nrmca.org/research/HVFAC_Final_Report_final.pdf 13
Why Why i is t the here a corre orrelation on? • Analytical studies of pullout test have been done Plasticity theory Compression-strut theory Aggregate-interlock theory • Pullout strength is related fundamentally to concrete strength 14
Pull llout F Fail ailure M Mech echan anism Compression strut theory 15
Pull llout F Fail ailure M Mech echan anism Compression strut theory 16
Com ompression on St Strut rut 17
Robust C t Correlatio elation Not affected by: • Type of cementitious materials • Water-cement ratio • Age • Air entrainment • Types of admixtures • Shape or size of normal density aggregate up to 40 mm Lightweight aggregate, however, produces significantly different correlation 18
Cub ube St Stre rength C h Corre orrelations 120 Johansen - LOK core f cube = 0.76 F 1.16 Gerhard - LOK Cube or Core Strength, MPa Winden - LOK 100 Winden - LOK Bellander - CAPO core Bellander - LOK core Bellander - CAPO 80 Bellander - LOK Worthers - CAPO Moczko - CAPO core Price - LOK 60 Price - LOK General Correlation 40 20 0 0 10 20 30 40 50 60 70 80 Pullout Force, kN 19
Cylin inder er S Stren ength th C Correlatio elations 120 100 f cyl = 0.69 F 1.12 Cylinder Strength, MPa Gay - LOK 80 Bickley - LOK Krenchel - LOK Krenchel - CAPO Krenchel - LOK Jensen - LOK 60 Drake - LOK Drake - LOK Poulsen - LOK Kierkegaard - LOK 40 Lekso - LOK Lekso - LOK Krenchel - LOK Krenchel - CAPO McGee - LOK 20 Bickley - LOK AEC - LOK & CAPO Obla - LOK General Correlation 0 0 20 40 60 80 100 Pullout Force, kN 20
Manufactu acturer er’s General C al Correlatio elations 100 Compressive Strength, MPa 1.16 f cube = 0.76 F 80 60 1.12 f cyl = 0.69 F 40 General Correlations for 20 Cylinder and Cube Strength 0 0 10 20 30 40 50 60 70 80 Pullout Load, kN 21
Pos Post-Insta tall lled ed P Pullo lout T t Test CAPO PO-Te Test • Does not require pre-planning test locations • Can perform test at any accessible location • Permits testing of existing structures • Immediate test results compared with cores 22
Pre Prepare C Conc oncre rete Plane surface Drill hole 18 mm 25 mm Cut slot 25 mm 23
Surf Surface Pl Plani ning 24
25
Cut ut Sl Slot ot 3.5 mm 25 mm 26
Cut ut Sl Slot ot 27
Cut ut Sl Slot ot 28
Ins nsert Exp Expansion C n Cone one and Coiled led S Split lit-Ri Ring g Coiled ring Cone 29
Ring E Expans nsion H n Hard rdware re Nut Bevel Coiled ring Cone 30
Exp Expand R Ring ng Nut 31
Pul Pullou out t the he Exp Expanded R Ring ng 32
33
CAPO PO-Tes est t vs L LOK-Te Test st 70 CAPO = b*LOK 60 Value Error b 1.0038 0.0051703 CAPO-Test Load, kN Chisq 112.19 1.3 kN 50 R 0.99593 40 30 Krenchel Bellander 20 Best-fit line 10 0 0 10 20 30 40 50 60 70 LOK-Test Load, kN 34
Cas Case S e Stu tudy November/December 2016 35
Pol Polish Bri ridge St Stud udy • Tested 15 bridges: ages 25 to 52 years • Measured depth of carbonation (2 to 35 mm) • Tested drilled cores with L/D = 1 to represent cube strength • Conducted companion CAPO tests • Used manufacturer’s correlation to estimate cube strength from CAPO-Test • Investigated effect of carbonation depth 36
Corre orrelation on 60 Core Strength Best fit curve: f core = 0.77F 1.15 50 Upper Confidence Limit Lower Confidence Limit Core Strength, MPa 40 General Correlation: f cube = 0.76F 1.16 30 20 10 0 0 5 10 15 20 25 30 35 40 CAPO-TEST, kN 37
Relativ ative E e Error − Estimated Cube Strength Core Strength α = × 100 % CT Core Strength 38
Sum Summary f for or 15 Bri ridges Bridge Carbonation Average core Average Estimated Relative error, No. depth, mm strength, MPa CAPO-TEST, compressive α CT , % kN strength, MPa 1 2 34.2 28.1 36.4 6.4 2 4 24.7 21.4 26.6 7.7 3 5 46.4 37.3 50.6 9.1 4 5 34.2 28.7 37.3 9.1 5 7 37.1 27.5 35.5 -4.3 6 7 42.0 30.1 39.4 -6.2 7 7 37.5 29.2 38.1 1.6 8 8 35.4 28.3 36.7 3.7 9 10 42.4 30.6 40.2 -5.2 10 19 33.3 24.9 31.7 -4.8 11 20 29.7 24.6 31.2 5.1 12 20 28.5 24.3 30.8 8.1 13 22 31.7 26.1 33.4 5.4 14 26 31.7 26.5 34.0 7.3 15 35 19.6 16.4 19.5 -0.5 39
Error v Error vs. C Carb rbon onation on D Depth 20 15 10 Relative Error, % 5 0 -5 Linear Fit -10 Value Error Intercept 3.2683 2.5763 Slope -0.033116 0.15923 -15 Sq. Error 441.56 NA R 0.057588 NA -20 0 5 10 15 20 25 30 35 40 Carbonation Depth, mm 40
Sum Summary • Pullout test offers the possibility of estimating in-place concrete with acceptable reliability • Stress state created by reaction ring leads to a compression strut that explains the good correlation with compressive strength • CAPO-Test allows testing without pre-placing inserts • Polish bridge study On average, CAPO-Test estimate was 3 % greater than core strength Carbonation did not appear to affect CAPO-Test results 41
Tha hank nk Y You ! ou ! 谢谢 42
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