9-07 RCC-KY Wayne Adaska

8/7/2019 9-07 RCC-KY Wayne Adaska

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Mix Design & Construction of RCC

Wayne Adaska, P.E.Director, Public WorksPortland Cement Association


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Dry enough tosu ort vibratorroller

Wet enough topermit adequatedistribution of paste


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Not air-entrained

Lower water content

Lower paste content

Nominal max. size aggregate +/- 5/8 in.


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evera me o s ava a e:

Soil compaction methods

Optimal paste volume method

Solid suspensions model


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Aggregate selectionvery important

Responsible for mix

workability,segregat on, ease oconsolidation

re- en e orstored separately


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Aggregate Selection

Select a sound, well- raded a re ate

For stability under vibratory roller, aggregateinterlock for load transfer, hi hest densit ,reduced segregation

Crushed or uncrushed ravel or crushed stone

Crushed aggregates:

Require more water

rov e grea er s a y, ess segrega on

Provide higher flexural strength


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Aggregate Selection

,

aggregates can be used.

Provides smooth surface, reduces segregation

Economic advantage using non-washed and pit-runaggregates including dense graded aggregate base

Provide adequate stability under vibratory roller

2%-8% passing #200 sieve

Supplements paste to fill voids and maintain tight surface


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Optimum Combined Gradation(Shilstone Method)

The Coarseness Factor Chart provides on

The 0.45 Power Chart shows a trend

Percent of aggregate retained on


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Sieve Size Percent Passing Actual

in mm Minimum Maximum Gradation

1" 25 100 100 100

"

1/2" 12.5 75 90 85.2

3/8" 9.5 65 85 75.0. .

#8 2.36 25 50 43.5

#16 1.18 20 40 34.2

#30 0.6 10 30 24.3

#50 0.3 7 20 10.6

. .

#200 0.075 2 8 0.7


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Coarseness Factor (CF) = % retained on 3/8 in. % retained on # 8 sieve x 100

Workability Factor (WF) = % passing #8 sieve + [ 2.5 x (lb/yd3

of cementitiousmaterial 564) / 94]


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Select cementitious materials

Blended cement: (C595 or C1157)

,(C1240)

-(12% to 17% of dry weight)

,

25%; silica fume typically 5% to 10%


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Determine moisture content

Modified proctor ASTM D1557

ssume a me an cemen con en e.g.500 pcy)


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-

144

143

144

lb

141

142

De

ty(

140

141

2% 3% 4% 5% 6% 7% 8%

Dry

2% 3% 4% 5% 6% 7% 8%Moisture Content


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e erm ne cemen ous ma er a s con en

Use optimum moisture content

Run cement series

e.g., 11%, 13%, 15%, 17%Select cement content which yields

appropriate strength.


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.

6,000

6,500

sve 725

697

5,500

Cmpe

nh(p

667

4,500

,

2DaC

Se

603

4,00010% 12% 14% 16% 18%

Cement Content


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e ar er or wa er re ucer can e use oincrease working time

Silica fume (7%) has resulted in

significant strength gainsAir entrainment not yet technologically

ossible, but

Experience has shown RCC can be madefreeze/thaw resistant


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Freeze-Thaw Durability

Field performance excellent, although not air

Minor surface paste (1/16) erodes, thensta zes

RCC results variable under ASTM C666 (F/T)and C672 (Deicer scaling)

Tests a ear to be too severe based on

actual experience

and precast units possibly more appropriate


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Freeze-Thaw Durability


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Sample RCC Mix Designs

Port of Tacoma

Units Intermodal Yard CTL Mix Canada Mix

Coarse Aggregate lb/cy 1,700 2,106 2,210Fine Aggregate lb/cy 1,700 1,378 1,338

% Finer Than #200 % 3 - 7 2 1

Cement lb/cy 450 504 470

Fly Ash lb/cy 100 0 36 (silica fume)

Admixture oz/cwt none none 5 (WR)

w/c ratio - 0.47 0.42 0.34

Unit Weight lb/cy 154.3 152.0 153.1

ompress ve: ay ps , , -

Compressive: 28 day psi 6,050 7,900 -

Flexural: 3 day psi 525 690 1,205

Flexural: 28 day psi 770 900 1,640


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Construction


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Subgrade preparation

Mixin rocess

Transporting

Compacting

JointingCurin


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Continuous Pug Mill

High-volume

Excellent mixing

materials

2 + n hr

Mobile, erected on site


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Highly accurateproportioning

Local availability

Smaller outputcapacity

Longer mix times than

conventional concreteFrequent cleaning

Dedicated production


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Highest local availability2-ste rocess

Feed into transit

mixersDischarge into dumps

Frequent cleaning


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Dry Concrete Batch Plant

mixer can aid inthorough mixing andplant throughput.


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Mobile Mixers


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Transporting

Rear dump trucksnormally used

Minimize transport

timeCovers required for

long hauls, or

o w n y con ons


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Transporting

Load in multiple piles


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Placing

La er thickness

4 in. minimum8 in. maximum 10 in. with heav -dut avers

Timing sequence

fresh joint, unless retarders used

Production should match paver capacity

u u w


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Placing Equipment

Hi h-densit aversVibrating screed

Dual tamping bars

Hi h initial densit 90-95%

Reduces subsequentcompaction

High-volume placement(1,000 to 2,000 cubic yardsper shift)

Designed for harsh mixes

Smoothest RCC surface


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Placement Equipment

Transfer equipment keeps paver fully charged


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Placing Equipment

Conventional asphalt pavers

Provide some initial density(80-85%)

Relatively smooth surface

May require modification

Increased maintenance


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Compaction

is critical for strengthand durabilit

Compact to 98%

Modified ProctorVibratory roller

Rubber-tire roller


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Must be constructed properly for durability

nsures on nter oc , so s a actsmonolithically

ree ypes o cons ruc on o n s:

Fresh joints

Horizontal joints


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Compaction more difficult

Segregation more likely

Try to minimize number of cold joints

Care needed to match rade from coldto fresh joint


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Edge Compaction

Compacting shoeompacting shoe


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-

unnecessary forerformance

Natural cracks provide

excellent load transferSaw-cut joints control

cracks for aesthetic

purposes


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Most economical

15 to 60 ft spacing

Often first cracksappear within 24 hours

arrow crac w s

Seal if > 1/4 in.

Minimal raveling

New, Unsealed

Crack

10-yr Old

Sealed Crack


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Saw-Cut Joints

More aesthetically

pleasing- ,

shortly following

lacementNeed to saw within 12

hours to avoid

uncon ro e crac ng 1/3 to 1/4 depth

conventional concrete


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Curin

Ensures surface durability; reduces dusting

Low moisture content in RCC; no bleed water

Moist cure

Asphalt emulsion

W C


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Water Cure

Typically 7-day specified

C C i C d


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Concrete Curin Com ound

White-pigmented concretecuring compounds

Application rate dependson surface texture

Surface Texture


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Surface Texture

Intermodal Yard, TX

Sludge Drying Bed, TX

Honda, ALarehouse Facility, WI


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Quality Control


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,

Plant calibration

Density tests

SmoothnessSurface texture

Strength


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ASTM D1557


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ASTM C1435

ASTM C1435


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Typically 3/8 in. over 10-ft length


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More Information


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www.cement.org/pavements


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Questions?Discover how beautiful concrete can be


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Prescriptive: Provides required properties,

and the method of installation.

Performance: Provides the required results,

criteria by which the performance will bejudged and the method by which it will beverified.


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ggrega e gra a on

T e of mixin lant

Type of paver

Type and size of compaction equipment

Method of curing


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Minimum strength

Pr i n r

Thickness

Smoothness


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Mix design/Compressive strength

Type of mixing plant/Production rate

Type and size of compactor/Density

Minimum number of passes/Density

9-07 RCC-KY Wayne Adaska

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