Quality Control and Robustness of SCC, Part 1

Size: px

Start display at page:

Download "Quality Control and Robustness of SCC, Part 1"

Ruby Phelps
6 years ago
Views:

Quality Control and Robustness of SCC, Part 1 ACI Spring 2012 Convention March 18 21, Dallas, TX Kamal H.

for Transportation Infrastructure and Safety. Dr. Khayat was Professor in the Department of Civil Engineering at the Universite de Sherbrooke in Quebec, Canada.

and Durable Materials and Structures. He received his.s., M.Eng., and M.S. in civil engineering with emphasis in structural engineering, construction engineering and management and a Ph.D. in civil engineering with emphasis in civil engineering materials, all from the University of California at erkeley.

He served as member of the Canadian Standards Association Committee A23.1/A23.2 and a number of TR Committees. He was elected fellow of ACI in 2004.

1 Quality Control and Robustness of SCC, Part 1 ACI Spring 2012 Convention March 18 21, Dallas, TX Kamal H. Khayat joined the Missouri S&T faculty in August of 2011 as the Vernon and Maralee Jones Professor of Civil Engineering and Director of the Center for Infrastructure Engineering Studies and Center for Transportation Infrastructure and Safety. Dr. Khayat was Professor in the Department of Civil Engineering at the Universite de Sherbrooke in Quebec, Canada. During his 21 years there, he served as the Director of the Center of Excellence on Concrete Infrastructure Engineering and Head of the Integrated Research Laboratory in Valorization of Innovating and Durable Materials and Structures. He received his.s., M.Eng., and M.S. in civil engineering with emphasis in structural engineering, construction engineering and management and a Ph.D. in civil engineering with emphasis in civil engineering materials, all from the University of California at erkeley. This was followed by a post-doctoral fellowship at the same institute. Dr. Khayat is active on several technical and code committees, including Chair of ACI 237 and RILEM Technical Committee 228. He served as member of the Canadian Standards Association Committee A23.1/A23.2 and a number of TR Committees. He was elected fellow of ACI in Evaluation of Robustness of SCC to Variations in Sand Humidity and Superplasticizer Dosage Kamal H. Khayat Soo-Duck Hwang Siwar Naji High Performance Flowable Concrete with Adapted Rheology ( ) Owners: Material Suppliers: Engineering Firms: Testing Labs: Prefab: Innovative materials and sustainable development Robustness of concrete is defined as capacity of the material to tolerate certain variations in material characteristics and mixture parameters Robust concrete has lower sensitivity to such variaitons Introduction Sand moisture content and dosage are considered as major parameters affecting robustness of SCC Objectives 1. Evaluate effect of - combinations on robustness of SCC subjected to small variations in sand humidity and dosage 2. Propose methodology to evaluate robustness 3. Identify test methods suitable for robustness evaluation 1

5 Types of s Reference SCC Codification PS1 PS2 Type Aninonic polysaccharide (Diutan gum-based) Maximum diameter of powder 180 µm (coarser grind) 75 µm (finer grind) PS3 Aninonic

02 CEL 0.05 MS 0.03 SSD condition (kg/m 3 ) w/c 0.37 Type GU cement 470 Water 175 Coarse agg. (MSA 14 mm) 900 Sand 870 6 L/m 3 3 L/m 3 (mass of water) 0.02% - 0.

: 3 polysaccharides s 1 modified starch 1 cellulosed-based Total 24 SCC mixtures Phase II.

Variation in sand humidity slump flow of 630 20 mm Phase II: Variation in dosage Testing Program Variation (w/cm) (12 SCC) (12 SCC) (3 SCC) (3 SCC) SSD (0.37) SSD 1% (0.

37), -10%, 0, +10% Control PS1 PS2 PS3 Control PS1 CEL MS Selected Selected Measurement Fresh Hardened Slump flow (10-45 ) Air content (10-45 ) Unit weight (10-45 ) T-50 (10-45 ) VSI

2 5 Types of s Reference SCC Codification PS1 PS2 Type Aninonic polysaccharide (Diutan gum-based) Maximum diameter of powder 180 µm (coarser grind) 75 µm (finer grind) PS3 Aninonic polysaccharide (Welan gum-based) 180 µm CEL Cellulose-based < 212 µm MS Modified starch combinations: and + 5 types type dosage (%) - - PS PS PS PS CEL 0.05 MS 0.03 SSD condition (kg/m 3 ) w/c 0.37 Type GU cement 470 Water 175 Coarse agg. (MSA 14 mm) 900 Sand L/m 3 3 L/m 3 (mass of water) 0.02% % Scope of Work Robustness of SCC Phase I. Variations in sand humidity -1% from SSD (w/cm = 0.35) SSD (w/cm = 0.37) +1% from SSD (w/cm = 0.39) 8 - combinations : vs. : 3 polysaccharides s 1 modified starch 1 cellulosed-based Total 24 SCC mixtures Phase II. Variations in dosage -10% less 0% (Reference) +10% more 2 selected SCC 1 + selected selected 2 Total 6 SCC mixtures Rheological properties Mechanical properties Phase I: Variation in sand humidity slump flow of mm Phase II: Variation in dosage Testing Program Variation (w/cm) (12 SCC) (12 SCC) (3 SCC) (3 SCC) SSD (0.37) SSD 1% (0.35) SSD + 1% (0.39) SSD (0.37) SSD 1% (0.35) SSD + 1% (0.39) SSS (0.37), -10%, 0, +10% SSS (0.37), -10%, 0, +10% Control PS1 PS2 PS3 Control PS1 CEL MS Selected Selected Measurement Fresh Hardened Slump flow (10-45 ) Air content (10-45 ) Unit weight (10-45 ) T-50 (10-45 ) VSI (10-45 ) J-Ring (10-45 ) Settlement Rheology Portable vane Inclined plane Slump flow with cylinder Compressive strength at 7, 28, and 56 days Flexural strength at 56 days Test Methods Effect of Sand Humidity on Surface Settlement Portable vane Inclined plane Slump flow with cylinder Maximum settlement (%) no -PS2 -PS1 -PS3 Incorporation of enhances robustness (low C.O.V.) -1% SSD 1% Sand humidity (% from SSD) 2

3 Effect of Sand Humidity on Yield Stress at Rest Yield stress at rest (MK 25 -no exhibits higher sensitivity in yield stress at rest to variation in sand humidity no -PS1 -MS CEL % SSD 1% Sand humidity (% from SSD) (8 properties) Air content (Vair) T-50 J-Ring Cylinder slump flow Robustness Rank Using C.O.V. PS1 PS2 PS3 C.O.V Rank C.O.V Rank C.O.V Rank C.O.V Rank Robustness Rank Using C.O.V. Robustness Rank Using C.O.V. (8 properties) PS1 PS2 PS3 Vair C.O.V Rank Slump flow C.O.V J-Ring Rank Cylinder C.O.V slump flow Rank Settlement C.O.V Rank Rheology rest (MK PS1 PS2 PS3 C.O.V Rank C.O.V Rank C.O.V Rank C.O.V Rank Robustness Rank Using C.O.V. (total 20 properties) Mechanical properties PS1 PS2 PS3 7-d fc C.O.V Rank d fc C.O.V Rank d fc C.O.V Rank d fr C.O.V Rank Ranking and Classification of Robustness to Sand Humidity - Sum of ranks, rmalized sum of Robustness Ranking SR i ranks* -PS % -PS % -PS % -PS % -MS % % -CEL % % *rmalized sum of ranks (%) = (Max. SR SR i ) / (Max. SR Min. SR)

4 rmalized sum of ranks (%) Ranking and Classification of Robustness to Sand Humidity Category Robustness Category I Very high -PS Category II High -PS3 -PS1 -PS Category III Medium -MS 30 Category IV Low -CEL - - Objectives 1. Evaluate effect of - combinations on robustness of SCC subjected to small variations in sand humidity and dosage 2. Propose methodology to evaluate robustness 3. Identify test methods suitable for robustness evaluation 19 2 SCC Mixtures for Phase II (Variation in dosage) Robustness of SCC Phase I. Variations in sand humidity -1% from SSD (w/cm = 0.35) SSD (w/cm = 0.37) +1% from SSD (w/cm = 0.39) 8 - combinations : vs. : 3 polysaccharides s 1 modified starch 1 cellulosed-based Total 24 SCC mixtures Phase II. Variations in dosage -10% less 0% (Reference) +10% more 2 selected SCC 1 + selected selected 2 Total 6 SCC mixtures Rheological properties Mechanical properties Methodology to evaluate Robustness C.O.V. and Deviation from Targeted Limit Value Compressive strength Variation limit for fc = 5% -10% 5% 0% +10% A = /A x 100 Higher rate of acceptance => More robust Lower limit (Mechanical properties, slump flow, J-Ring) 22 Deviation from Targeted Limit Value Slump flow Surface settlement Variation limit for settlement = 10% -10% 0% 10% +10% Upper limit (Settlement and rheology) A = /A x 100 Higher rate of acceptance => More robust Slump 10 (mm) -PS3 A = /A x 100 = 84% -10% 0% 10% dosage (% from Control) 655 -PS1: 49% Lower limit (3% from Control, 592 mm)

5 Yield Stress at Rest (Inclined Plane) -PS3 is more robust than -PS1 -PS3 800 Yield stress at rest 25 (Pa) 455 A % 0% 10% dosage (% from Control) = /A x 100 = 135% > 100% Upper limit (5% from Control, 500 Pa) 330 Rate of Acceptance Values Phase II -PS3 -PS1 7-d fc d fc d fc d fr Slump flow at J-Ring at Settlement T-50 at rest (MK rest rest (MK Mean Robustness (C.O.V. and Rate of Acceptation) Objectives Coefficient of Variation (%) Properties -PS3 -PS1 -PS3 -PS1 7-d fc d fc d fc d fr Slump flow at J-Ring at Settlement T-50 at rest (MK rest rest (MK Mean Evaluate effect of - combinations on robustness of SCC subjected to small variations in sand humidity and dosage 2. Propose methodology to evaluate robustness 3. Identify test methods suitable for robustness evaluation 27 Properties selected for robustness evaluation 11 Properties for Robustness Evaluation 20 properties 1. 7-d fc d fc d fc d fr 5. Vair at T-50 at J-Ring at Cylinder slump flow Vair 10. Slump flow J-Ring at Cylinder slump flow 12. Settlement rest (MK rest (MK rest Rate of structural buildup (PV) Kendall s Coefficient of Concordance Spearman s Rank Correlation 11 properties 1. 7-d fc d fc d fc d fr 5. Air content (Vair) at Settlement rest (MK rest (MK rest Rate of structural buildup (PV) Robustness of SCC Incorporating Different Viscosity-Enhancing Admixtures, ACI Materials Journal, 108 (4), 2011, pp Spearman's rank correlation Higher Spearman s rank correlation => higher correlation between ranks based on each property and those on all properties

6 Conclusions SCC made with is more robust than SCC with Incorporation of enhances robustness Mixtures made with polysaccharide s are more robust than those prepared with modified starch and cellulosed-based s Either COV or rate of acceptance methodology can be used to evaluate robustness Conclusions Sstatistical approach based on Kendall s coefficient of concordance and Spearman s rank correlation was used to identify key properties of SCC that can be used to assess robustness of SCC. Characteristics that can be used to evaluate robustness include air volume, J-Ring, surface settlement, static yield stress (PV), rheometer, as well as flexure and compressive strengths. Min. testing program to evaluate robustness should include: Compressive strength at 28 days Surface settlement Yield stress at rest (concrete rheometer or portable vane) 6

CHARACTERIZATION OF SELF COMPACTING CONCRETE IN TERMS OF BINGHAM CONSTANTS

CHARACTERIZATION OF SELF COMPACTING CONCRETE IN TERMS OF BINGHAM CONSTANTS H.M.G.U. Karunarathna, DRD Unit, Central Engineering Consultancy Bureau, Colombo 7, Sri Lanka gayanud@gmail.com H. Abeyruwan,