Can I Produce Roller Compacted Concrete? What a Ready Mix Producer Needs to Know to Get in the Game - 1 -

Transcription

1 Can I Produce Roller Compacted Concrete? What a Ready Mix Producer Needs to Know to Get in the Game - 1 -

2 Part 1 Introduction to RCC AGENDA Mix Design Process Mix Production Equipment and Standard Process Hauling Part 2 Partnering / Projects / Manage Expectations Paving & Rolling Equipment Curing & Sawcutting Equipment Things to Watch out For, What Can Go Wrong! - 2 -

3 ROLLER COMPACTED CONCRETE IS A ZERO SLUMP CONCRETE A negative-slump concrete that is compacted not consolidated. Placed with High Density Asphalt Machine No forms. No reinforcing steel or dowels. No finishing. Compacted with rollers. No internal vibration. (consistency of damp gravel). RCC is a concrete pavement that is designed & placed in a different way! - 3 -

4 MULTIPLE PERSONALITIES Concrete rigid pavement Portland Cement Roller-Compacted Concrete Asphalt paver compaction Soils Proctor test density test Moisture Content - 4 -

5 HOWEVER, THE BIGGEST THREAT TO OUR INDUSTRY IS BAD PROJECTS TYPICALLY COMPLETED BY UNEDUCATED PRODUCERS AND CONTRACTORS - 5 -

6 RCC PAVEMENT COUNCIL IS AN INDUSTRY ORGANIZATION FOCUSED ON PROVIDING RESOURCES FOR RCC

7 THERE ARE EXCELLENT TECHNICAL RESOURCES AVAILABLE Developed by the CPTech Center at Iowa State Covers all aspects Available through PCA Guideline specification for Exposed Surface RCC pavements - 7 -

8 THE FINAL SURFACE TYPE WILL DICTATE THE NECESSARY TECHNIQUES & EQUIPMENT NEEDED TO BE SUCCESSFUL Natural RCC Diamond Ground RCC Asphalt Applications Ports Distribution centers Industrial yards Residential roads Parking lots Collector / Arterial local roads Highway Shoulders State routes Any pavement type Factors Lowest Cost Most sensitive to contractor skill level Least smooth Asphalt appearance Medium cost increase Increased construction time Improved smoothness, skid resistance Reduced noise Highest cost Increased construction time Least sensitive to contractor skill level Improved smoothness, skid resistance - 8 -

9 THE SURFACE APPEARANCE AND TEXTURE OF RCC IS SIMILAR TO ASPHALT PAVEMENT Similar appearance & texture as asphalt only light grey instead of black Surface texture depends on aggregate gradation and paste content Diamond ground RCC is similar to diamond ground concrete Diamond Ground Conventional Concrete PCC RCC Diamond Ground RCC HMA - 9 -

10 WHAT DOES IT TAKE FOR A GOOD PROJECT? Right Equipment Know How: Find someone to help you. Practice. Practice again. Good Specification Follow Specification Enforce Specification

11 Part 1 Introduction to RCC AGENDA Mix Design Process Mix Production Equipment and Standard Process Hauling Part 2 Partnering / Projects / Manage Expectations Paving & Rolling Equipment Curing & Sawcutting Equipment Things to Watch out For, What Can Go Wrong!

12 RCC MIX DESIGN USES SAME MATERIALS AS CONVENTIONAL CONCRETE, HOWEVER IN DIFFERENT COMBINATIONS Achieves Similar or Better Engineering Properties Than Conventional Concrete 60 Typical Mix Design Typical Engineering Properties Conventional (psi) RCC (psi) % Total Weight Cement + FA Coarse Agg Fine Agg Water Compressive Strength 3,000-5,000 4,000-7,000 Flexural Strength (MOR) Elastic Modulus million Conventional Concrete ,000 RCC million Conventional Concrete Roller Compacted Concrete

13 MIXTURE DESIGN: AGGREGATE SELECTION Step 1: Select Coarse Aggregate, Intermediate Aggregate, & Sand Most important aspect of mix design (85% of mixture) Selection based on gradation test results of available aggregates Quantity of aggregate sources depends on # of aggregate bins at production plant Need to achieve a balance of angularity and surface appearance Screed Stability Workability Surface Appearance Strength Roller Marks Compaction Segregation Moisture Content Durability Fatigue Shrinkage Cold Joint Stability We Currently Do Not Know How a Mix Will Perform Until Putting it Through a Paving Machine!

14 WHAT AGGREGATE & MIX PROPERTIES IMPACT THOSE PERFORMANCE CHARACTERISTICS? How Do We Measure Them? How much does it Matter? What About the impact of the mix combination? Aggregate Shape Top Size Size Distribution Mineralogy Absorption Sand Type Screed Stability Workability Surface Appearance Strength Roller Marks Compaction Segregation Ideal Moisture Content Durability Fatigue Shrinkage Cold Joint Stability

15 MIXTURE DESIGN EXAMPLE RCC Aggregate 45 Power Gradation Max Density Gradation Plot Percent Passing (%) RCC Spec Upper Limit Spec Lower Limit 1/2 in Power 45 3/4 in Power 45 1 in Power #200 #100 #16 # 4 3/8" 1/2" 3/4" 1" Sieve Size

16 TYPICAL COMBINED AGGREGATE GRADATION SPECIFICATION Sieve Size Sieve Size Percent passing by weight Lower & Upper Specification Limits ½ in Maximum Lower & Upper Specification Limits ¾ in Maximum / ½ / No No No No No No No

17 MIXTURE DESIGN EXAMPLE Combined Aggregate Grading Sieve Size: Bin Number Aggregate Producer: Quarry Location: Aggregate Type: Aggregate Name: Nominal Max Agg Size Sieve Analysis Date/Info: Individual Bin (%): Sieve Size: (mm) Total Bin 25.0 Percent 55.0 Percent 20.0 Percent 100.0% Cum.% Passing Bin No.2 CEMEX Cache Creek S&G Crushed Rock 3/8" x 1/4" Crushed 1/2" Aug Ave. Sieve Alaysis Data Wtd Cum. % Concrete Sand Cum.% Passing Bin No.3 CEMEX Cache Creek S&G Natural Sand Aug Ave. Sieve Alaysis Data Wtd Cum. % Bin No.6 Cum.% Passing CEMEX Cache Creek S&G Crushed Rock 1/2" x #8 3/4" Aug Ave. Sieve Alaysis Data Wtd Cum. % Combined Gradation Cum. % Passing Within Spec's Top Agg Size 12 Low er & Upper RCC paving Specification Limits 1" 3/4" 1/2" 3/8" No. 4 No. 8 No. 16 No. 30 No. 50 No. 100 No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes

18 MIXTURE DESIGN PROCEDURE Step 2: Select a mid range cementitious content Minimum 450 lbs cement / CY 12% Type I Portland cement is selected for the first trial batch Based % on weight, so make enough and do not worry about volumes yet Mix the cement dry, and then add water Step 3: Develop moisture density relationship plots Perform a modified Proctor test at the selected cement content Construct moisture-density relationship curve (Use spreadsheet) Determine Maximum Dry Density (MDD) and Optimum Moisture Content (OMC) (ASTM D1557) Maximum Dry Density Optimum Moisture

19 WHICH MAXIMUM DENSITY DO I USE? Reference Wet Density Reference wet density (RWD): RWD = (MDD) x (1+ OMC) Where MDD = Maximum Dry Density OMC = Optimum Moisture Content Determined in the lab in accordance with ASTM D1557 Source: ASTM D1557: Standard Test Method for Laboratory Compaction Characteristics of Soil Using Modified Effort

20 MIXTURE DESIGN: COMPACTION TEST REPORT Compaction Test Report 154 RWD: pcf % = pcf Density (pcf) Dry Density Wet Density % Moisture

21 Mix Quantities Max Dry Density (lbs/cf) Max Wet Density (lbs/cf) Optimum % Moisture Coarse Aggregate #1 absorption % Fine Aggregate #1 absorption % Coarse Aggregate #2 absorption % Fine Aggregate #2 absorption % % Cementitious % Cement % Fly Ash (of cement replace) % 1.1% 1.7% 1.1% 0.0% 11.5% 11.5% 0.0% Target CA #1 % 1/2" x #8 20 Target FA #1 % Concrete Sand 55 Target CA #2 % 3/8" x 1/4" Crushed 25 Target FA #2 % 0 0 MIXTURE DESIGN EXAMPLE Proctor Test Aggregate Properties Combined Gradation

22 Mix Quantities Max Dry Density (lbs/cf) Max Wet Density (lbs/cf) Optimum % Moisture Coarse Aggregate #1 absorption % Fine Aggregate #1 absorption % Coarse Aggregate #2 absorption % Fine Aggregate #2 absorption % % Cementitious % Cement % Fly Ash (of cement replace) % 1.1% 1.7% 1.1% 0.0% 11.5% 11.5% 0.0% Target CA #1 % 1/2" x #8 20 Target FA #1 % Concrete Sand 55 Target CA #2 % 3/8" x 1/4" Crushed 25 Target FA #2 % 0 0 MIXTURE DESIGN EXAMPLE Mix Weight (lbs) Per CY Water Weight = ( ) x 27 = 211 Total Dry Materials = x 27 = Select Cement content 2. CA = (Total Dry-cement) x % Target CA = ( ) X.2 = 693 SSD Weight 1. CA = Dry weight x (1 +%SSD) Ingredient Cement Batch Weight (Dry) (lbs/cy) Batch Weight (SSD) (lbs/cy) Specific Gravity (SSD) Absolute Volume (CF) Fly Ash CA #1 1/2" x # FA #1 Concrete Sand CA #2 3/8" x 1/4" Crushed FA# Total Water content (lbs) Water in Aggregates (lbs) Water added by Plant (Free Water) (lbs)

23 MIXTURE DESIGN EXAMPLE Ingredient Cement Batch Weight (Dry) (lbs/cy) Batch Weight (SSD) (lbs/cy) Specific Gravity (SSD) Absolute Volume (CF) Fly Ash CA #1 1/2" x # FA #1 Concrete Sand CA #2 3/8" x 1/4" Crushed FA# Total Water content (lbs) Water in Aggregates (lbs) Water added by Plant (Free Water) (lbs) The Typical Mix Design parameters can then Total Wet Weight (lbs/cf) be calculated Total Dry Weight (lbs/cf) Total Final Volume (CF) Calculated Air Volume (CF) Calculated % Air Volume % Water absorbed in Aggregates Free Water W/CM Ratio Aggregate / Cement Ratio

24 Step 4: Cast samples to measure compressive strength (ASTM C 1435) Calculate trial mix proportions Batch RCC materials Maintain percent Optimum Moisture Content as determined in step 3 Use varying cementitious contents such as 10, 12 and 14 percent Make compressive strength test cylinders for each cement content MIXTURE DESIGN PROCEDURE

25 ADMIXTURES CAN BE USED TO IMPROVE WORKABILITY, INCREASE HAUL TIME, AND ALLOW FOR TROWELLED FINISH Intended Goals of the Research Increase haul time while maintaining workability Retain moisture Improve surface finish Increase compressive strength Increase density behind paver Currently using Grace 3 cwt

26 Part 1 Introduction to RCC AGENDA Mix Design Process Mix Production Equipment and Standard Process Hauling Part 2 Partnering / Projects / Manage Expectations Paving & Rolling Equipment Curing & Sawcutting Equipment Things to Watch out For, What Can Go Wrong!

27 TWIN SHAFT OR PUGMILL MIXER ARE NEEDED FOR HIGHER PRODUCTION RATES OR LARGE QUANTITIES Mixer Type Photo Factors to Consider Pugmill Continuous Twin Shaft High production rates: 100 to 300+CY / hr Excellent mixing efficiency for dry materials Highly consistent mix properties, minimal moisture fluctuation easy adjustment Mobile 1 load, 1 day set up and & calibratetion Need to find good location, obtain permits Self contained Gen set, batch house 2 to 3 man operation # of Aggregates depends on Feeder system Twin Shaft Horizontal Mixer - Batch Type High production rates: 50 to 100 CY / hr depends on RM Plant capacity Excellent mixing efficiency for dry materials Mobile 1 load, easily set up in 1 day Batch setup moisture monitoring difficult Mixing system only requires a batching system Same capabilities & requirements as operating ready mix plant No permitting required Easy to incorporate admixtures, fibers, etc

28 CONTINUOUS RCC MIXING PLANT (PUGMILL) IN ACTION

29 TRADITIONAL MIXING EQUIPMENT CAN BE USED ON SMALLER PROJECTS WITH LOWER PRODUCTION RATE REQUIREMENTS Mixer Type Photo Factors to Consider Central Mix Good for demonstrations & smaller applications 20 to 60 CY/hr reduced batch size, increased mixing time Typically at fixed locations Mixing consistency is average depends on batch size & mixing time Batch to batch moisture fluctuations can be high (+/- 0.4%) Easy to incorporate admixtures, fibers, etc Dry Batch Readily available in most locations Slow production - only used on small projects Poor mix consistency, and slow mixing due to small batch size, increased mix time Material must be transferred from mixing truck to dump truck Moisture control is inconsistent Trucks must be dedicated to RCC Test to ensure mix can get out of mixer NOT Recommended

30 PRODUCTION RATE IS DICTATED BY SET UP 6 CY Batch 2 Trucks, 1 Loader, 3 Dump Trucks 26 Mins / 12 yard Dump (23-31 Mins) 13.8 CY / hr / Truck = 26 CY/ hr 108 CY Total: 4 hr 11 mins

31 BIGGEST FACTOR TO CONSIDER DURING MIX PRODUCTION 1. Moisture control Moisture control Moisture control! 0.5 gallon = 0.1% moisture Before production begins, measure moisture in stockpile Measure moisture in mixture continuously with stove, reduce as project proceeds Maintain stockpile moisture content consistent build stockpiles early Consume the stockpile in a consistent manner

32 HOW DO YOU KNOW WHERE TO BEGIN PRODUCING? Compaction Test Report 1. Produce Test Optimum Moisture Content 2. Measure moisture content RWD: pcf 3. Use calibrated hand test / debate 4. Produce test Optimum + ½% % = pcf 5. Measure Moisture content 6. Use calibrated hand test / debate Send 1 or 2 trucks to job site 8. Take moisture content 9. Place 1 st load 10. Measure density behind paver Density (pcf) Dry Density Wet Density 11. Look at surface appearance 12. Make adjustments as needed Measure density behind paver until eyes are calibrated % Moisture

33 Density (pcf) MIXTURE DESIGN What Is The Optimal Paving Moisture Content? Too Dry Optimal Paving %m Too Wet Pro Stable mix RWD: behind paver pcf & rollers Good grade control Fast rolling, cure & saw cut 98% = pcf Con Low density behind paver High chance for segregation Surface becomes more open High chance of ravelling Low surface durability Cold joints ravel Saw cuts spall Pro Good density behind paver Stable mix behind paver & rollers Good grade control Minimal to no segregation Good Cold joints Acceptable surface appearance Clean Sawcuts % Moisture Pro High Density behind paver Low mix segregation Good cold joints Tight Surface appearance Clean sawcuts Con Dry Instable Density mix Wet Density behind paver Poor grade control Delay roller compaction time Delay curing time Delay sawcutting time

34 MIXTURE DESIGN What Aggregate Properties Change the Optimal Paving Moisture Content Window?? 154 Too Dry Optimal Paving %m Too Wet RWD: pcf % = pcf Density (pcf) Dry Density Wet Density % Moisture

35 2 ND MAJOR FACTOR TO CONSIDER DURING MIX PRODUCTION 2. Aggregate Segregation Aggregate selection (smaller top size, multiple sizes) Stockpile management Loader operator Mixing Process Delivering mix to paver Paver operation

36 3 RD MAJOR FACTOR TO CONSIDER DURING MIX PRODUCTION 3. Production rate to meet paver demand Primary factor in plant type selection paver needs to keep moving as smoothness, compaction are negatively impacted when paver stops Ensure cement delivery is planned, cement pigs when needed Width (ft) Depth (in) Speed (ft / min) Production Rate (CY / HR)

37 Part 1 Introduction to RCC AGENDA Mix Design Process Mix Production Equipment and Standard Process Hauling Part 2 Partnering / Projects / Manage Expectations Paving & Rolling Equipment Curing & Sawcutting Equipment Things to Watch out For, What Can Go Wrong!

38 1. Adequate number of trucks for consistent mix delivery to paver 2. Plant location should be within 30 minutes of paving location (without admixtures), with admixtures no more than 1 hour. 3. Cover the Load HAUL TRUCKS 4. Do not stack-up trucks waiting to deliver RCC to paver allowing mix to dry out - Avoid the asphalt mentality

39 1. Adequate number of trucks for consistent mix delivery to paver 2. Plant location should be within 30 minutes of paving location (without admixtures), with admixtures no more than 1 hour. 3. Cover the Load HAUL TRUCKS 4. Do not stack-up trucks waiting to deliver RCC to paver allowing mix to dry out - Avoid the asphalt mentality

40 Part 1 Introduction to RCC AGENDA Mix Design Process Mix Production Equipment and Standard Process Hauling Part 2 Partnering / Projects / Manage Expectations Paving & Rolling Equipment Curing & Sawcutting Equipment Things to Watch out For, What Can Go Wrong!

41 Three keys to successful RCC projects Partner with a Good Paving Contractor Pick the Right Project Put RCC in a place where it can succeed Manage the expectations of the owners

42 Partner with a Good Paving Contractor

43 Partner with a Good Paving Contractor They get the projects not you They can place RCC and do it well however most don t know that yet.

44 Pick the right project

45 Pick the right project

46 Pick the right project

47 Pick the right project

48 Pick the Right Project Maybe?

49 Pick the Right Project Maybe?

50 Pick the Right Project No (But)

51 Manage the Expectations

52 Manage the Expectations

53 Manage the Expectations

54 Manage the Expectations

55 Part 1 Introduction to RCC AGENDA Mix Design Process Mix Production Equipment and Standard Process Hauling Part 2 Partnering / Projects / Manage Expectations Paving & Rolling Equipment Curing & Sawcutting Equipment Things to Watch out For, What Can Go Wrong!

56 1 st KEY TO A QUALITY PROJECT: GOOD KNOWLEDGEABLE SUPERINDENDANT IN THE RIGHT PLACE

57 RCC PAVING PROCESS IS SIMILAR TO ASPHALT PAVING Achieving Density & Smoothness is Critical

58 RCC IS PLACED WITH ASPHALT PAVERS Achieving Density & Smoothness is Critical Standard Paver (4-6 Thick) Single Lift Low initial density from paver (80% - 85%) Available in all locations High-production (6 to 8 ft/min) Lift thick range: 4 to 6 Good when RCC topped with asphalt Requires more compaction to achieve density (grade control problems) Easier to fix segregated areas before compaction High Density Paver (4-9 Thick) Dual Lift High density screed (Vogele or ABG Titan) High initial density from paver (90% - 98%) Smoother surface due to higher initial density Less roll down to achieve final density High-production (4 to 8 ft/min) Wide Paving Widths (24 to 30 ft wide) Lift thick range: 4 to 9 Strongly RECOMMENDED

59 Fixed Width Standard mass across the full width SCREED TYPES Variable or Fixed Width? Can be built out to very wide widths (>15m) Require high volume supply when paving wide Suitable for regular shaped areas Unsuitable for varying paving widths Available in tamping/vibrating/hd Variable Width Very adaptable for complex paving shapes Typical widths between 2.5 and 5m Additional extensions similar to fixed screeds Available in tamping/vibrating/hd Paver of choice for most applications

60 DEVELOP A WELL THOUGHT OUT PAVING PLAN Paving plan should be completed for all sites Step by Step sequence of installation Joints should be planned and documented Construction joints away from stress areas Plan is heavily reliant on supply output Transport considerations e,g delays etc

61 IN-PLACE WET MAT & JOINT DENSITY TESTING TEST STANDARD PRECISION MIN. FREQUENCY ACCEPTANCE ASTM C pcf (d2s) CY Ave. of 4 98% RC 0 < 96% RC

62 MIXTURE DESIGN: COMPACTION TEST REPORT Compaction Test Report 154 RWD: pcf % = pcf Density (pcf) Dry Density Wet Density % Moisture

63 FABRICATING COMPRESSION TEST CYLINDERS EQUIPMENT

64 LONGITUDINAL JOINTS CAN BE BUILT 3 DIFFERENT WAYS Cold Vertical Joint Angular Cold Joint Fresh Vertical Joints Pave width of lane Saw cut full depth early next morning Remove with blade & loader Expect waste Reduce waste with paver shoe & plate tamper Pave adjacent lane and match thickness of existing lane Good performance, limited load transfer Need high density paver Attach shoe to screed Maximum angle 15 o Use plate tamper to improve edge durability No saw cutting required Pave adjacent lane next day Lowest cost Pave for 50 minutes then move back to beginning and match original lane Do not compact original lane within 2 ft of edge until adjacent lane is paved Recommend a longitudinal saw cut Use small loader to create fresh vertical transverse joint Move quickly keep moist! Coordination is key, avoid breakdowns 2 ft

65 DON T LET JOINTS DRY OUT, CLEAN UP LOOSE MATERIAL

66 DON T LET JOINTS DRY OUT, USE HEAVY DOSE OF CONFILM TO PREVENT MOISTURE LOSS

67 COLD JOINTS PERFORM BEST WHEN PAVED STRAIGHT

68 BAD JOINT CONSTRUCTION = SURFACE ABRASION AND SPALLING

69 SAWCUT COLD JOINTS CLEAN (Don t Let Transverse Fresh Joints Dry Out)

70 BE ON THE LOOKOUT FOR SEGREGATION IN THE SURFACE vs

71 FINAL COMPACTION & ROLLERS Initial Compaction Initial: ton static & vibratory roller Establish roll pattern (check density a lot!) Adjust roll pattern based on moisture content Compact to 98% density - wet Adjust moisture content if needed impacts smoothness & compaction Finish Rolling Combination, dual steel or rubber tired Weight - 3 to 6 ton Remove roller marks Once completed, keep roller off of the area Grape Creek Road San Angelo, TX Fairforest Way Greenville, SC Florida RCC Davenport, Fl

72 Part 1 Introduction to RCC AGENDA Mix Design Process Mix Production Equipment and Standard Process Hauling Part 2 Partnering / Projects / Manage Expectations Paving & Rolling Equipment Curing & Sawcutting Equipment Things to Watch out For, What Can Go Wrong!

73 CURING Curing Applied at same rate or slightly higher than conventional concrete Ensure uniformity with application process Apply as soon as possible behind roller operation Recommend WR Meadows 1200 to 1600 Ensures durable surface

74 SAW CUTTING Saw Cut & Fill Joints More aesthetically pleasing Early entry saw very effective, shortly following placement Recommend sawing within 2-6 hours to avoid uncontrolled cracking Depth: ¼ depth of RCC Spacing: Maximum 30 times thickness, Maximum 15 to

75 Part 1 Introduction to RCC AGENDA Mix Design Process Mix Production Equipment and Standard Process Hauling Part 2 Paving & Rolling Equipment Curing & Sawcutting Equipment Teaming & Communication Practice Things to Watch out For, What Can Go Wrong!

76 Poor Durability along longitudinal paving joints Paver passes

77 Poor Durability along longitudinal paving joints Paver passes

78 Poor Durability along longitudinal paving joints Paver passes

79 Poor Surface Appearance Labeled as Poor Surface Durability

80 Poor Surface Appearance Causes and Cures?

81 Subgrade Failure

82 A SUCCESSFUL PROJECT IS POSSIBLE Lake View Heroes Road San Angelo, TX

83 Florida RCC Davenport, FL

84 Tri County Rural Electric Westfield, PA

85 Sol Epoxy Olean, NY

86 Questions? Corey J. Zollinger, P.E Wayne Stephen Jim Casilio, P.E