Longitudinal Joints and Indiana Update

NCAUPG March 18, 2016

Matt Beeson, P.E.

INDOT Office of Materials Management State Materials Engineer

INDOT Joint Specification Joint failures 2010 DOT/Industry Committee

INDOT Joint Specification Construction method specs?

Notched wedge Plate Compactors Joint Compactors

Industry experience was negative Question of whether density really improved Also constructability questions

INDOT Joint Specification Joint Density specification?

More core holes (at the joint!) Taking cores directly over the joint

problematic What Gmm to use? Joint isn’t vertical

Another pay factor

INDOT Joint Specification Joint Adhesive

Hot applied Top two lifts (intermediate and surface)

Fog Seal Emulsion 1 ft. on each side of joint

INDOT Joint Specification

Centerline Rumble Stripes

Centerline Rumble Stripes

Centerline Rumble Stripes

Centerline Rumble Stripes

Longitudinal Joints

Longitudinal Joints Better ideas? Still a problem?

What’s going on in Indiana? HMA mixes seem low on binder

Why?

Aggregate Gsb 2013

Mix Design review Inflated Gsb values

2014 Designs required to use INDOT Gsb

5 year moving average of data Fixed value for RAP (2.640)

Unless outside of 2.600-2.680

Mix Design

19.0 mm mixture Gsb = 2.665 Gmm = 2.490 Gmb = 2.390 Pb = 4.1 VMA = 13.6%

Mix Design

19.0 mm mixture Gsb = 2.665 Gmm = 2.490 Gmb = 2.390 Pb = 4.1 VMA = 13.6%

Mix Design

19.0 mm mixture Gsb = 2.665 Gmm = 2.490 Gmb = 2.390 Pb = 4.1 VMA = 13.6% Gse = 2.651

Mix Design

Gsb = 2.665 Gse = 2.651

Pba = -0.20%

Mix Design

Pba = -0.20% Negative Absorption

Obviously doesn’t happen Absorption actually happens when mix

is produced Where does it come from? The effective asphalt content!

Reality

19.0 mm mixture Real Gsb = 2.600 2.665 Gse = 2.651 Real Pba = 0.76% -0.20% Real VMA = 11.8% 13.6%

Reality

How much more binder? Incorrect Pba = -0.20% Real Pba = 0.76% 0.76% - (-0.20%) = 0.96% Pb = 4.10% + 0.96% = 5.06%

“Binder Deficient” by almost 1.0%

Problem Solved?

Gsb list since 2014 Mix design Gsb is much more

accurate Another loophole First example – Gsb inflation Next example – Gse deflation

Mix Design

19.0 mm mixture Gsb = 2.600 Gmm = 2.430 Gmb = 2.332 Pb = 4.1 VMA = 14.0%

Mix Design

19.0 mm mixture Gsb = 2.600 Gmm = 2.430 Gmb = 2.332 Pb = 4.1 VMA = 14.0%

Mix Design

19.0 mm mixture Gsb = 2.600 Gmm = 2.430 Gmb = 2.330 Pb = 4.1 VMA = 14.0% Gse = 2.579

Mix Design

Gsb = 2.600 Gse = 2.579

Pba = -0.32%

Reality

19.0 mm mixture Gsb = 2.600 Real Gse = 2.651 Real Pba = 0.76% -0.32% Real VMA = 11.8% 14.0%

However, this time, VMA was actually

measured in the field as 11.8% Only 10% of pay!

Delta Pb

Compute combined H2O absorption Estimated Pba = 65% H2O

Compare design Pb to estimated Pb We are calling this “Delta Pb” Currently ΔPb ≤ 0.4% = OK

Statewide Total Binder Content

9.5 mm 2013 2014 2015

Mean 5.6 5.8 5.9

12.5 mm 2013 2014 2015

Mean 5.0 5.4 5.5

19.0 mm 2013 2014 2015

Mean 4.4 4.5 4.8

25.0 mm 2013 2014 2015

Mean 4.1 4.2 4.4

Vbe = Durability

VMA = Important Do you really know what your VMA

(Vbe) is? Is the Gsb accurate? Does the Gsb match the material used? Is Pba reasonable? Did materials change in production?

What are we doing next?

Pay factors rebalance to emphasize VMA

Continue using Gsb list for designs Track Gse from design to field

If Gse changes, verify Gsb

Turns out Gsb testing is reliable from an extracted HMA sample

Extracted Aggregate Gsb

Batched 18 samples “Dummy” mix design 2000g stone

+4 only

1000g sand -4 only 500g/500g stone sand/nat. sand

T84/T85

Extracted Aggregate Gsb

4.5% AC 0, 2, 4, 6 hr. STOA per R 30 Centrifuge extraction w/ TCE Separate +4, -4 Rerun T84/T85

Extracted Aggregate Gsb

2.6

2.605

2.61

2.615

2.62

2.625

2.63

2.635

2.6 2.605 2.61 2.615 2.62 2.625 2.63 2.635

Bef

ore

Extr

acti

on

After Extraction

Total Sample

No Aging

No Aging - 1000g Stone Sand

No Aging - 500g Stone Sand/500g Natural Sand

2 Hour Aging

4 Hour Aging

6 Hour Aging

Extracted Aggregate Gsb

0.85

0.95

1.05

1.15

1.25

1.35

1.45

0.85 0.95 1.05 1.15 1.25 1.35 1.45

Bef

ore

Extr

acti

on

After Extraction

Total Sample

No Aging

No Aging - 1000g Stone Sand

No Aging - 500g Stone Sand/500g Natural Sand

2 Hour Aging

4 Hour Aging

6 Hour Aging

Extracted Aggregate Gsb

2.500

2.550

2.600

2.650

2.700

2.750

2.800

2.500 2.550 2.600 2.650 2.700 2.750 2.800

Test

ed

Expected

65 designs 137 tests

Extracted Aggregate Gsb

2.500

2.550

2.600

2.650

2.700

2.750

2.800

2.500 2.550 2.600 2.650 2.700 2.750 2.800

Test

ed

Expected

n ≥ 2 28 designs 96 tests

What are we doing next?

We want to measure properties as accurately as possible Air Voids, Density already reliable VMA will now be (more) reliable

Further trials with Superpave5 to improve durability

Look at performance testing

Questions?

Matt Beeson, P.E. State Materials Engineer

(317) 610-7251 x204 mbeeson@indot.in.gov