Optimized Mixtures for Sustainable Concrete Pavements in WI

Transcription

1 WCPA 2015 Annual Concrete Pavement Workshop Best Western Premier Waterfront Hotel and Convention Center Oshkosh Feb 12, 2015 Optimized Mixtures for Sustainable Concrete Pavements in WI WHRP Dr. Konstantin Sobolev Dr. Steve Cramer Dr. Ahmed Faheem Mohamadreza Moini Dr. Ismael Flores Vivian Scott Muzenski Rani Pradoto Justin Flickinger Konstantin Sobolev Presentation February 12, of 51

2 Outline Research Program Materials Characterization and Properties Optimization of Admixtures Aggregates Optimization Experimental Packing vs. Theoretical Models What is the Best Packing/Blend for Concrete Mixtures? Preliminary Concrete Study Concrete Tests (470 lb/yd 3 ) Reduced Concrete Tests (420 lb/yd 3 ) Final Concrete Mixtures: Southern/Northern Aggregates Fresh and Hardened Durability Results and Discussion Konstantin Sobolev Presentation February 12, of 51

3 Goals: WCPA Annual Concrete Pavement Workshop Project Goals & Scope Develop guidelines for optimized concrete mix design through performance evaluation of a range of concrete mixtures. Scope: Develop a testing matrix for comprehensive testing of aggregate gradations, SCMs and HRWR admixtures in concrete. Evaluate and compare the composition, microstructural features, and physical properties of different types of cementitious materials essential for their compatibility with HRWR admixtures affecting their performance in concrete. Evaluate the effect of SCMs and HRWR admixtures on the stability of air void system, fresh properties (slump and air content), mechanical performance (compressive and flexural strength), and durability (freeze thaw resistance and rapid chloride permeability) of concrete. The results will recommend the aggregate gradations and dosage of superplasticizers/hrwr admixtures that will accommodate the use of reduced cementitious materials for the low slump concrete paving mixtures. Konstantin Sobolev Presentation February 12, of 51

4 Problem Statement WisDOT is interested in reduced cementitious materials content than meet the specs: 470 lb/yd 3 (279 kg/m 3 ) vs. standard 517 to 565 lb/yd 3 (306 to 335 kg/m 3 ) Specs: 2 4 in slump 3 days to open for traffic (3000 psi / 20 MPa) F/T Durability ASTM 666 RCP Durability AASHTO T 277 or ASTM 1202 Previous research: concrete with reduced cementitious materials content had an adequate durability; however, these mixes frequently demonstrated poor workability and strength. Current WisDOT practice does not address the use of optimized aggregates gradation. Therefore, a research on aggregate optimization is needed to support the development of specifications including best aggregate combination for a sustainable concrete paving mixtures. Konstantin Sobolev Presentation February 12, of 51

5 Proposed Approach WHRP requests to perform a long term strength and durability investigation of optimized superplasticized concrete (the total cementitious materials content of 470 lbs/yd 3 ) based on two types of superplasticizers/ HRWR admixtures (polycarboxylate, PCE and sulfonated naphthalene formaldehyde, SNF), two sources of coarse aggregates (combined with local sands and optimized), and representative cementitious materials consisting of three sources of portland cement, two types of slag cement (grade 100 and 120) and two types of fly ash (Class C and Class F). Optimized concrete is a complex six component material (two aggregate binary cementitious mix with superplasticizer and AE admixture); therefore, full scale optimization of such concrete is very comprehensive task. The problem can be simplified in the case when the total cementitious materials content and/or W/Cm are fixed as specified by the WHRP RFP. Konstantin Sobolev Presentation February 12, of 51

6 Materials and Experiments 3 types of cement 2 types of aggregates 7 types of chemical admixtures 3 types of air entraining admixtures 3 types of supplementary cementitious materials 80 aggregate combinations tested for packing degree for S/N Aggregates. 91 mortars and 58 pastes with SCMs and chemical admixtures were tested for screening and dosage optimization, and to study the effect of SCM s. 67 preliminary concrete mixtures tested for Southern Aggregate 40 Preliminary concrete mixtures tested for Northern Aggregates 26 preliminary reduced cement content concrete mixtures (420 lb/yd3) tested for best approach study 27 big batches (100 liters) produced and tested for each type of aggregates Konstantin Sobolev Presentation February 12, of 51

7 Materials: Experimental Matrix Exp. Matrix ADM # set CEM SCM AGG ADM Total Mixtures Sub Total SP1 PCE superplasticizer 1 C1/C2/C3 AG1/AG2 PL+AE 6 SP2 SNF superplasticizer 2 C1 AC AG1/AG2 PL+AE 2 PL plasticizer 3 12 AE AE admixture 4 C1 S1 AG1/AG2 PL+AE 2 AGG 5 C1 AF AG1/AG2 PL+AE 2 AG1 aggregates combination 6 C1/C2/C3 AG1/AG2 SP1+AE 6 AG2 aggregates combination 7 C1 AC AG1/AG2 SP1+AE 2 CEM 8 12 C1 cement 9 C1 S1 AG1/AG2 SP1+AE 2 C2 cement 10 C1 AF AG1/AG2 SP1+AE 2 C3 cement 11 C1/C2/C3 AG1/AG2 SP2+AE 6 SCM 12 C1 AC AG1/AG2 SP2+AE 2 AF fly ash type F, 30% AC fly ash type C, 30% 14 C1 S1 AG1/AG2 SP2+AE 2 S1 slag 100, 50% 15 C1 AF AG1/AG2 SP2+AE 2 S2 slag 120, 50% Total Opti 1 36 Mix Type Opti 1 # set CEM SCM AGG ADM Total Mixtures Sub Total cement = 470lb/yd3 1 C1/C2/C3 AG1/AG2 PL+AE 6 6 slump= 50mm (1 4 in.; < 2.5 in. s.form) W/C = reduced (for mixtures with SPs) vs. spec. 501 Air= 4 8% (6 + or 1.5) Opti 2 cement = 420(400) lb/yd3 1 C1/C2/C3 AG1/AG2 SP1+AE 6 slump= 50mm (1 4 in.; < 2.5 in. s.form) 2 C1 AC AG1/AG2 SP1+AE 2 W/C = same as spec C1 S1 AG1/AG2 SP1+AE 2 5 C1 AF AG1/AG2 SP1+AE 2 Total Opti 2 18 Total Testing 54 Konstantin Sobolev Presentation February 12, of 51

8 Materials Properties Cement CHEMICAL Item ASTMC150 Test Result Limit Lafarge Holcim St.Marys SiO 2, % Al 2 O 3, % Fe 2 O 3, % CaO, % MgO, % 6.0 max SO 3, % 3.0 max Na 2 O, % K 2 O, % Others, % Ignition loss, % 3.0 max PHYSICAL Spec. Test Result Item Limit Lafarge Holcim St.Marys Density, g/cm Time of setting, minutes Initial 45 min Final 375 max Normal Consistency Aggregates Designation Location Name C1 Sussex Pit Sussex, WI Low Chert 1"Limestone I1 Lannon Quarry Lannon, WI Low Chert 5/8"Limestone F1 Sussex Pit Sussex, WI Washed Torpedo Sand Konstantin Sobolev Presentation February 12, of 51

9 Aggregate s Properties Southern Northern Specific Gravity Density, kg/m 3 ID Type (OD) (SSD) (OD) (SSD) WAbs., % < 75µm, % C1 Limestone I1 Limestone F1 Torpedo Sand C2 Glacial Gravel I2 Glacial Gravel F2 Igneous Sand Konstantin Sobolev Presentation February 12, of 51

10 Chemical Composition of Fly Ash Chemical composition, % Class FClass C ASTM C 618 limits Class F Class C Silicon Oxide, SiO Aluminum Oxide, Al 2 O Iron Oxide, Fe 2 O Total, SiO 2 +Al 2 O 3 +Fe 2 O min 50 min Sulfur Trioxide, SO max 5.0 max Calcium Oxide, CaO Magnesium Oxide, MgO Potassium Oxide, K 2 O Sodium Oxide, Na 2 O Moisture Content max 3.0 max Loss on Ignition max 6.0 max ASTM C 618 limits Physical Tests Class FClass C Class F Class C Specific Gravity Water Requirement, % of Control max 105 max Konstantin Sobolev Presentation February 12, of 51

11 XRD of Fly Ash Class C and F Konstantin Sobolev Presentation February 12, of 51

12 SEM images Fly ash Class C (FA C) Fly ash Class F (FA F) Konstantin Sobolev Presentation February 12, of 51

13 Properties of Chemical Additives Admixture Brand Composition Specific gravity, g/cm 3 Solid Content, % Air Entraining Terapave AEA Sodium C14 16 Olefin Sulfonate Air Entraining Daravair 1000 Neutralized Resin Acids and Rosin Acids Air Entraining MB AE 90 Potassium hydroxide; Sodium Hydroxide Air Entraining Micro Air Tall oil, Fatty acids, Polyethylene glycol Water Reducing Admixture Pozzolith 80 4 chloro 3 methyl phenol High range water reducing Glenium 7700 Polycarboxylate ether High range water reducing Rheobuild 1000 Naphthalene sulphonate based High range water reducing ADVA Cast 600 Polyacrylate Aqueous Solution High range water reducing Daracem 19 Naphthalenesulfonic acid polymer High range water reducing Disal Sodium Salt of poly(naphthalene sulfonic acid) High range water reducing Megapol 40 DF Methacrylic acid copolymer Konstantin Sobolev Presentation February 12, of 51

14 Admixture Optimization: Flow of Mortars Flow, % PCE PCE SNF SNF Dosage, % HD1 HAC HG7 HR1 RP8 Konstantin Sobolev Presentation February 12, of 51

15 Admixture Optimization: Air Entrainment Density, g/cm PCE SNF HD1 HAC HG7 HR1 RP Mid Range Dosage, % Konstantin Sobolev Presentation February 12, of 51

16 Admixture Optimization: Strength Compressive Strength, MPa Ref RP8 (0.1%) RP8 (0.15%) RP8 (0.2%) HR1 (0.15%) HR1 (0.2%) HR1 (0.3%) HR1 (0.4%) HG7 (0.05%) HG7 (0.1%) HG7 (0.15%) HG7 (0.2%) 3 days 7 days 28 days Konstantin Sobolev Presentation February 12, of 51

17 Heat of Hydration Heat Flow, mw/g Dry Binder 6 5 L L+P Time, hours L Lafarge Cement P Polycarboxilate (Glenium 7700) S Slag F Class F Fly Ash C Class C Fly Ash Konstantin Sobolev Presentation February 12, of 51

18 Proposed Approach Superplasticized Fly Ash Concrete ASTM C 109 Heat Flow, mw/g Dry Binder Ref HG7(0.15%) FAF(30%) HG7(0.15%) FAC(30%) HG7(0.15%) SL(50%) HG7(0.15%) Time, hours Konstantin Sobolev Presentation February 12, of 51

19 Aggregates Optimization: Experimental Packing VeBe Test : Is previously used to measure the consistency of RCC and low slump concrete (ASTM C1170): Filling container Striking with rod Vibration Vibration + Compaction Different Methods are proposed by researchers for Dry Packing Density of aggregates with different compaction index for experimental packing of aggregates. VeBe Apparatus is used for as a standard tool to measure packing density of 40 different aggregate combinations in 2 states: Pouring (Loose) Vibration (45s) + Compaction (Compacted) Konstantin Sobolev Presentation February 12, of 51

20 Experimental Packing Packing Density (kg/m3) Exp. Packing for C1, F1, I1 Blends: % I 0% I % I % I F1 % Packing Density (kg/m3) Exp. Packing for C2, F2, I2 Blends: % I % I % I % I F2 % The max. packing occurs at 60% F1. The practical limitations impose 40% F1. The max. packing occurs at 70% F1. The practical limitations impose 50% F1. Konstantin Sobolev Presentation February 12, of 51

21 Experimental Packing vs. Model Experimental Results and Regression Model Response for C1, F1, I1: C.S. 7 C.S. had similar trend Loose vs. Compacted: C.P.D. (%) y = x R² = L.P.D. (%) Konstantin Sobolev Presentation February 12, of 51

22 Classical Models Aim Model: Model suggested in 1967 takes into account: i. Takes into account the interaction of larger particles on packing of smaller particles based on Furnas model wall effect (F>>C) ii. Describes the packing degree as: 1, for F dominant for C dominant 2, Toufar Model: Model suggested in 1976 [5] is based on Furnas model and takes into account: i. Diameter ratio (k ) ii. probability of the number of interstices between coarse particles (k ) iii. Describes the packing degree as: α Uses three experimental values as : 1 r α r α r 1 α 1 k k Modified Toufar Model: Characteristic Diameter Eigenpacking Degree Grain Density Modified Toufar Model suggested in 1997 and corrects the (k ) Konstantin Sobolev Presentation February 12, of 51

23 Experimental Packing vs. Models Model Response for C1, F1, I1 Blends: Model Response for C2, F2, I2 Blends: Konstantin Sobolev Presentation February 12, of 51

24 Aggregates Optimization: Virtual Aggregate Packing 86% packing 500 disks N=10 Kr=1.005 Ks= 10 Sr = % Packing 1000 Spheres N= 100k Kr= Ks= 1.5 Sr= Konstantin Sobolev Presentation February 12, of 51

25 Mix ID Compacted Packing Degree (PD C ) Experimental Packing vs. Models Loose Packing Degree (PD L ) F1, % I1, % C1, % Slump (mm) Bulk Density (kg/m3) Air Content (%) C.S. MPa (7days) C.S. MPa (28days) Best Fit n St. Dev. Input Output # of Spheres Red. Coef. Sep. Coef. Step Sep. St Best St. # of Trials P.D. (K red..) (k.) (S..) dev. fit n dev. fit 1 5 Million fit 2 5 Million Percent Passing Mix 1 Mix 2 power 0.64 power Aggregate Size (mm) 10 Percentage Passing fit 1, 5 Million Spheres 80.0 Fit 2, 5 Million Spheres Particle Size (Micorn) Konstantin Sobolev Presentation February 12, of 51

26 Aggregate Blends vs. Power Curves Percent Passing Northern Aggregates: C1, F1, I Aggregate Size (mm) Percent Passing Southern Aggregates: C2, F2, I Aggregate Size (mm) Power 0.7 Power 0.5 Power 0.45 Power F 30I 30C 50F 20I 30C 50F 10I 40C 40F 10I 50C 35F 10I 55C 60F 0I 40C 55F 0I 45C 40F 0I 60C Konstantin Sobolev Presentation February 12, of 51

27 Concrete Mixtures: 470 lb/yd 3 (280 kg/m 3 ) Packing Degree (%) R² = R² = R² = R² = Loose 28 Days Comp. 28 Days Loose 7 Days Comp. 7 Days Compressive Strength (MPa) Konstantin Sobolev Presentation February 12, of 51

28 Aggregates Characterization Individual Percentage Retained: SouthernAgg F 10I 37.5C 35F 10I 55C 50F 20I 30C 40F 30I 30C 55F 0I 45C 50F 10I 40C 60F 0I 40C 40F 0I 60C 40F 10I 50C Power 0.7 Power 0.35 (8 band) (18 band) Aggregate Size (mm) Konstantin Sobolev Presentation February 12, of 51

29 Aggregates Characterization Individual Percentage Retained: NorhternAgg F 10I 37.5C N 35F 10I 55C N 50F 20I 30C N 40F 30I 30C N 55F 0I 45C N 50F 10I 40C N 60F 0I 40C N 40F 0I 60C N 40F 10I 50C N Power 0.7 Power 0.35 (8 band) (18 band) 45F 10I 45C N Aggregate Size (mm) Konstantin Sobolev Presentation February 12, of 51

30 Shilestone Workability and Coarseness Factors Southern Aggregates 45C 55F 0I 37.5C 52.5F 10I 55C 35F 10I 30C 50F 20I 30C 40F 30I 40C 50F 10I 40C 60F 0I 60C 40F 0I 50C 40F 10I 45C 45F 10I 50C 50F 0I WF CF Northern Aggregates 45C 55F 0I 37.5C 52.5F 10I 55C 35F 10I 30C 50F 20I 30C 40F 30I 40C 50F 10I 40C 60F 0I 60C 40F 0I 50C 40F 10I 45C 45F 10I 50C 50F 0I WF CF Konstantin Sobolev Presentation February 12, of 51

31 Experimental Matrix and Fresh Properties Legends: C1: Cement type 1 C2: Cement type 2 C3: Cement type kg/m 3 (470 lb/yd 3 ) R 249 kg/m 3 (420 lb/yd 3 ) S: Slag Cement Grade 100 C: Class C Fly Ash F: Class F Fly Ash M: Mid Range: 4 chloro 3 methyl phenol (WRA) N: SNF: Naphthalene Sulphonate based SP (HRWRA) P: PCE: Polycarboxylate ether SP (HRWRA) W/C was adjusted to satisfy workability requirement (2 4 in slump) 279 kg/m3 (470 lb/yd3) 249 kg/m3 (420 lb/yd3) Chem. Admix. Dos.(%) W/C Slump (mm) Air Labels PCE SNF Mid 0 30 AE Range min mins % C1 S M C1 S N C1 S P C1 S M S C1 S N S C1 S P S C1 S M C C1 S N C C1 S P C C1 S M F C1 S N F C1 S P F C2 S M C2 S N C2 S P C3 S M C3 S N C3 S P C1 S M R C1 S P R C1 S P C R C1 S P S R C1 S P F R C2 S M R C2 S P R C3 S M R C3 S P R Konstantin Sobolev Presentation February 12, of 51

32 Concrete Mixtures: 470 lb/yd 3 (280 kg/m 3 ) Density (kg/m3) y = x R² = Air (%) Konstantin Sobolev Presentation February 12, of 51

33 Mechanical Performance Results: The mixtures containing Class C fly ash PCE HRWR and Slag concrete had superior performance 279 kg/m3 (470 lb/yd3) 249 kg/m3 (420 lb/yd3) Labels W/C Compressive Strength (MPa) Flexural Strength (MPa) L S M BB L S N BB L S P BB L S M S BB L S N S BB L S P S BB L S M C BB L S N C BB L S P C BB L S M F BB L S N F BB L S P F BB H S M BB H S N BB H S P BB S S M BB S S N BB S S P BB L S M R BB L S P R BB L S P C R BB L S P S R BB L S P F R BB H S M R BB H S P R BB S S M R BB S S P R BB Konstantin Sobolev Presentation February 12, of 51

34 Mechanical Performance Early Strength and Strength Development : The mixtures with Class C fly ash, PCE HRWR, and slag cement had superior performance W/C 0.37 W/C C.S. (MPa) 30 C.S. (MPa) Days Days C1 S M C C2 S N C1 S N C C2 S M C1 S M S C1 S N S C1 S N C1 S P C1 S P S C3 S P C2 S P C1 S M C3 S N C1 S N F Konstantin Sobolev Presentation February 12, of 51

35 Mechanical Performance Early Strength and Strength Development : The mixtures containing Class C fly ash, PCE HRWR, and slag cement had superior performance W/C 0.37 Reduced C W/C 0.42 Reduced C C.S. (MPa) Days C.S. (MPa) 30 C1 S P C R 20 W/C 0.45 Reduced C C.S. (MPa) Days Days C1 S P S R C2 S M R C3 S M R C2 S P R C1 S P R C3 S P R C1 S P F R C1 S M R Konstantin Sobolev Presentation February 12, of 51

36 C.S. vs. F.S. correlation Southern Aggregates Flexural Strength, MPa Reference Slag Class F Class C y = x R² = Compressive Strength, MPa Konstantin Sobolev Presentation February 12, of 51

37 RCP Performance 30 days: Labels The mixtures containing Slag, Class C fly ash Had a very low permeability 90 days: The mixtures containing Class F fly ash Had a very low permeability Significant Improvement: Class F fly ash 279 kg/m3 (470 lb/yd3) 249 kg/m3 (420 lb/yd3) W/C Air RCP Charge Passed (Coulomb) % 30 days 90 days Drop % C1 S M BB C1 S N BB C1 S P BB C1 S M S BB C1 S N S BB C1 S P S BB C1 S M C BB C1 S N C BB C1 S P C BB C1 S M F BB C1 S N F BB C1 S P F BB C2 S M BB C2 S N BB C2 S P BB C3 S M BB C3 S N BB C3 S P BB C1 S M R BB C1 S P R BB C1 S P C R BB C1 S P S R BB C1 S P F R BB C2 S M R BB C2 S P R BB C3 S M R BB C3 S P R BB Konstantin Sobolev Presentation February 12, of 51

38 RCP Performance C3 S P C3 S N C3 S M C2 S P C2 S N C2 S M C1 S P F C1 S N F C1 S M F C1 S P C C1 S N C C1 S M C C1 S P S C1 S N S C1 S M S C1 S P C1 S N C1 S M 90 days 30 days Charge Passed (Coulombs) 30 days: The mixtures containing Slag, Class C fly ash had very low permeability 90 days: The mixtures containing Class F fly ash had very low permeability Significant Decrease: Class F fly ash Konstantin Sobolev Presentation February 12, of 51

39 RCP Performance C3 S P R C3 S M R 90 days 30 days C2 S P R C2 S M R C1 S P F R C1 S P S R C1 S P C R C1 S P R C1 S M R Charge Passed (Coulombs) 30 days: The mixtures containing Slag, Class C fly ash had very low permeability 90 days: The mixtures containing Class F fly ash had very low permeability Significant Decrease: Class F fly ash Konstantin Sobolev Presentation February 12, of 51

40 Freeze Thaw Performance The mixtures containing Class C fly ash PCE HRWR and Slag had superior performance Reduced C Mixtures had outstanding performance Labels W/C Air DF Mass Loss % % % C1 S M BB C1 S N BB C1 S P BB C1 S M S BB C1 S N S BB C1 S P S BB C1 S M C BB C1 S N C BB C1 S P C BB C1 S M F BB C1 S N F BB C1 S P F BB C2 S M BB C2 S N BB C2 S P BB C3 S M BB C3 S N BB C3 S P BB C1 S M R BB C1 S P R BB C1 S P C R BB C1 S P S R BB C1 S P F R BB C2 S M R BB C2 S P R BB C3 S M R BB C3 S P R BB Konstantin Sobolev Presentation February 12, of 51

41 Freeze Thaw Performance Some mixtures containing Mass Loss PCE without SCMs gained mass C3 S P C3 S N C3 S M C2 S P C2 S N C2 S M C1 S P F C1 S N F C1 S M F C1 S P C C1 S N C C1 S M C C1 S P S C1 S N S C1 S M S C1 S P C1 S N C1 S M Mass Loss (%) Konstantin Sobolev Presentation February 12, of 51

42 Overall Performance Mixtures with Reduced Cement : The mixtures containing Mass Loss Mid range and PCE without SCMs gained mass C3 S P R C3 S M R C2 S P R C2 S M R C1 S P C1 S P C1 S P C1 S P R C1 S M R Mass Loss (%) Konstantin Sobolev Presentation February 12, of 51

43 Superplasticizer: Conclusions and Recommendations The use of superplasticizer (PCE/SNF) enables to improve the performance of AE concrete with cement content of 420 lb/yd3 at w/c < 0.5 and even 0.45 when Fly C was used with PCE. The compressive strength of reference concrete with midrange plasticizer (#15) was at the level of 20 MPa (3000 psi) and 30 MPa (4500 psi) at the 7 and 28 days respectively. The use of SNF resulted in concrete of similar performance as reference midrange water reducer. PCE admixture was superior to reduce the W/C and improve the strength of mixtures with reduced cementitious material content and, especially, with SCMs. The use of PCE resulted in concrete (based on southern aggregates) of higher strength up to 33 MPa (4784 psi) and 38 MPa (5693 psi ) at 7 and 28 days, respectively. Similar results were demonstrated for concrete based on Northern aggregates. The use of PCE and class C fly ash improved the strength to 38.1 MPa (5524 psi) and 49.3 MPa (7153 psi) for 7 and 28 days, respectively (southern aggregates). The use of PCE and fly ash F resulted in a concrete with strength as high as 25 MPa (3741 psi) and 40 MPa (5855 psi) at the age of 3 and 28 days, respectively. Konstantin Sobolev Presentation February 12, of 51

44 The Effect of SCMs: Conclusions and Recommendations Use of selected SCMs is beneficial in terms of durability and strength development. The contribution of SCM depends on the properties/type of SCM. However, concrete with class F fly ash may have a low strength insufficient to meet the DOT spec. Fly ash C had an exceptional compatibility with superplasticizers, especially PCE type. The w/cm in the mixtures with PCE was reduced to 0.32 and 7 and 28 day strength was increased to 35.5 MPa (5150 psi) and 46.7 MPa (6770 psi), respectively. Concrete with class F Fly ash had marginal performance. Only combination with PCE was enabled to obtain the strength similar to reference. Still improvement of class F concrete strength at later ages may be expected. Reduced dosage (15%) of fly ash F or combination with fly ash C can be suggested to improve the early age performance. Slag cement concrete increased the strength even in reduced cementitious material content mixtures. Konstantin Sobolev Presentation February 12, of 51

45 Conclusions and Recommendations Aggregates Optimization: The early age strength of concrete can be increased by up to 15% using optimization of aggregate proportions, particularly, incorporating intermediate aggregates (up to 30%). Aggregate optimization may require to use up to 50% of sand in the mix. The intermediate aggregate is beneficial for concrete performance and can be used up to 30% replacing coarse aggregate. Optimal Mixtures (C:I:F) were 40:10:50 for Southern aggregates and 50:10:40 for Northern aggregates. The power curves can be used as an additional criteria to select the best aggregate combination. Based on the experimental results, the power curve based on the level of workability should be selected for optimizing the best blend. Konstantin Sobolev Presentation February 12, of 51

46 Conclusions and Recommendations Reduced Cement Content: The reduction of cementitious materials content to 279 kg/m3 (420 lb/yd3) is possible with careful selection of mix components and optimization of aggregates. The strength reduction was up to 20% (due to increase of w/cm). Also these mixtures had lower workability and were more difficult to compact. The use of fly ash C with PCE was beneficial so the strength was even higher than reference, 28.7 MPa (4160 psi) and 39.8 MPa (5770 psi) for 7 and 28 days, respectively. However, the workability of these mixtures was somehow low (1 of slump). The adjustment for slump may require the increase of w/cm to the unacceptable levels higher than 0.55 which may compromise the durability. Only fly ash potentially C concrete may be effectively designed at very low cementitious material content of 249 kg/m3 (420 lb/yd3). Cement Type Study: 3 types of cement investigated had different performance especially in early age, which may effect the performance of concrete with SCMs. These cements were not optimized for admixture type and dosage (which may potentially improve the performance) Konstantin Sobolev Presentation February 12, of 51

47 Durability: RCP Conclusions and Recommendations The concrete based on portland cement had the highest RCP. The specimens with SCM's had the lowest RCP values, specially after 90 days of curing. The addition of slag presented the lowest RCP values at all testing ages. Class F fly ash presented a minor reduction of the RCP values at 30 days in comparison to the reference mixes; however, at 90 days of curing the RCP values were significantly reduced. Overall, the SCM's reduce the permeability of the concrete due to the pozolanic reactions, especially at longer curing ages. Durability: Freeze Thaw All investigated concrete types based on Southern aggregates had a durability factor of more than 90%. Concrete specimens produced with reduced cement presented a larger length change than those made at higher cement volumes. Mixes with SCM's had lower length change values, most probably due to the pozolanic reaction and the development of denser cementitious matrix. Konstantin Sobolev Presentation February 12, of 51

48 Experimental Methods: Educational Module Konstantin Sobolev Presentation February 12, of 51

49 ACKNOWLEDGMENTS WisDOT NSF UWM RGI & UWM Foundation Lafarge Zignego Ready Mix CFIRE WE Energies BASF WR Grace Handy Chemicals Kuraray Konstantin Sobolev Presentation February 12, of 51

50 Konstantin Sobolev Presentation February 12, of 51

51 THANK YOU!!! More info at: super beton.com Questions? E mail: sobolev@uwm.edu Konstantin Sobolev Presentation February 12, of 51