Center for Dirt and Gravel Roads DSA Clearinghouse · PDF fileWe just ask that, at a minimum, you report your DSA placements to us and share any lab data you may have for the material

Center for Dirt and Gravel Roads DSA Clearinghouse

Eric Nevel – [email protected]

DSA Clearinghouse Driving Surface Aggregate

What is a DSA Clearinghouse?

- The “DSA Clearinghouse” will act as a central data repository for DSA projects and provide DSA testing services if needed

- The purpose of this DSA Clearinghouse is to ensure quality DSA purchase and placements for Conservation Districts statewide by:



1. Establishing a “DSA Expert” and a central point of contact for quarries on DSA issues.

2. Visiting and talking with quarries to insure they

understand the DSA requirements. 3. Collecting samples and performing testing to

ensure DSA meets all material requirements before delivery and placement.



4. Keeping records of aggregate testing and sharing with others to avoid duplicating efforts.

5. Assistance with contractor coordination.

6. On-site assistance during DSA placement.


When can I use the DSA Clearinghouse?

Immediately, we unofficially have already begun systematic sampling of quarries statewide. For now, contacting The Center before DSA placements is voluntary, HOWEVER….


New Policy for DSA Placements When the new DGLVRP administrative manual is approved by the SCC, it will contain the following language: “The Center has undertaken an initiative called a ‘DSA Clearinghouse’ to improve the quality and consistency of Driving Surface Aggregate statewide. Conservation Districts are required to contact the Center for Dirt and Gravel Road Studies when a contract is awarded involving DSA.”


New Policy for DSA Placements This new policy will not affect local control of the program!!! - The Center can be as involved or uninvolved in your DSA

placement as you would like.

- We just ask that, at a minimum, you report your DSA placements to us and share any lab data you may have for the material you purchase.


How do I use the DSA Clearinghouse?

- Contact the Center as far in advance (30 days, if possible) as possible about DSA placements to allow adequate time for material sampling, testing, and analysis.

- Last minute notifications (two weeks or less) may not allow time for proper coordination and testing

- What happens next?



- The exact procedure that occurs when a Conservation District calls the DSA clearinghouse will vary based on the experience of CD staff with past DSA projects, but in general, the DSA Clearinghouse will:



1. Review the past history of chosen DSA supplier with the Conservation District.

2. Ensure CD staff is familiar with DSA requirements

and recommendations. If needed, based on the comfort level of CD staff and past testing history of the quarry being used: 3. Provide third-party testing services to ensure DSA quality before delivery.



4. Communicate with the quarry about any potential quality issues before delivery.

5. Assist CD staff with site preparation and DSA placement.

6. Educate CD staff on DSA issues, quality control, placement

issues, testing methodology and options, etc. 7. Be available on-site during DSA placement.

8. Add any testing results obtained by the Center or the District to the DSA database in order to share with other Conservation Districts.



- Use the DSA Purchase Notification Form

- Will most like be an online form on the CDGRS website


Why have a DSA Clearinghouse?

- When the Dirt & Gravel Program was a $5 million/year program, roughly $2-3 million dollars was spent each year on DSA - With funding increased to $27 million (SCC and DCNR) for Dirt and Gravel Roads, we could easily spend $10-15 million per year on DSA.



- DSA is, by far, is the most visible and expensive part of a dirt road - For some CD’s, DSA has been an easy way to

spend program funds with minimal thought and effort.

- We want to make sure that program funds are actually being spent on DSA, not clay-ridden aggregate.



- Since DSA was created, the Program and Center have had a difficult time in controlling the amount of clay that some quarries put into their DSA mix



- In 2012, DCNR-BOF began to require plasticity testing on all DSA projects



- This has led to a more consistent, higher quality DSA product

- However, we have caught quarries selling rejected DCNR DSA stockpiles to townships in the D&G program because they knew we wouldn’t test it


Why have a DSA Clearinghouse? Since we began sampling and testing, 35% of the DSA we’ve tested has been out of spec!!! These were not surprise inspections of the quarry



- As per SCC board approval at their meeting on 3/11/14, a maximum Plasticity Index (PI) of 6 was added to the SCC DSA specification.

- Ideally, this means that all DSA stockpiles will be tested for plasticity before any DSA placement.

- Remember, the D&G Program DOES NOT CERTIFY QUARRIES!! We only certify individual stockpiles of DSA.

FRONT

DSA ESMPs DSA Clearinghouse

Plasticity Index

SCC Certification - A cert from a quarry does not mean that the DSA has been properly tested and meets the specification.

- This form is just a way for the quarry to say the material they are delivering meets the spec

- NEVER ACCEPT MATERIAL BASED ON A CERT FROM THE QUARRY!!!

DSA ESMPs DSA Clearinghouse

Lab Testing - We need independent testing from a disinterested third party lab.

-While testing for plasticity, the lab can also test gradation, pH, LA Abrasion, and also do a proctor test.

- What is DSA?

- Details of DSA specification

- Purchasing DSA

- DSA placement


DSA is the ONLY approved surface material in the DGLVRP for unpaved roads.

* Note that surface material is not required for every site

An aggregate specification created by the Dirt and Gravel Road Program for use as a wearing course on unpaved roads

DRIVING SURFACE AGGREGATE


DSA Technical Bulletin on Handout Table

WHAT IS DSA? Similar to PennDOT’s “2A”, but:

- Smaller top size and more fine material for better compaction

- More strict specifications ( size, hardness, moisture, etc)

DSA ESMPs What is DSA?

DSA Technical Bulletin on Handout Table

WHAT IS DSA?

Advantages of DSA: - Better compaction - More durable - Tighter specification (narrower gradation, more

fines, hardness spec, clay limitations)

DSA ESMPs What is DSA?

- What is DSA?

- Details of DSA specification

- Purchasing DSA

- DSA placement


- What is DSA? - Details of DSA specification

- Size or Gradation - Plasticity Index - Hardness - Moisture - pH

DSA Specification Driving Surface Aggregate

Road surface Road surface

Base

A mixture of large stones will fail!! What is good aggregate?

1”

DSA ESMPs Specification Details Size or Gradation


Base

A mixture of small stones will fail!! What is good aggregate? 1”


Trail surface Trail surface

A surface that’s too sandy will fail!! What is good aggregate?

1”


Base

INCLUDING FINES!


Base

A good mix of stone sizes…..

So what will work? What is good aggregate?

1”


Rock “FINES” are the glue that holds DSA together!


Gradation: what does this really mean?

Passing Sieve

Lower % Higher %

1½ inch 100 - 3/4 inch 65 95

#4 (1/4 ") 30 65 #16 (1/16 ") 15 30

#200(1/200 ") 10 15

% passing by weight The DSA spec: What does this really mean?


20%

12.5% 25% 10%

32.5% “Midline” Percent by weight


DSA Fines: Remember we said:

“FINES” ARE THE GLUE THAT HOLDS DSA TOGETHER!

DSA “Fines” must be crushed rock!

Crushed rock fines from other sources that meet DSA standards can be added. - Limestone fines can be added to sandstone aggregate (and reverse). - Up to 50% of fines can be made up of Lime/Cement Kiln Dust.


Tighter specification with more fine material allows for better compaction than traditional aggregates.

DSA: 10-15% crushed rock fines 2A: 0-10% ??? fines

Better compaction leads to a better, harder, longer lasting road.

DSA Size Gradation in a nutshell:





DSA ESMPs Specification Details Plasticity Index

NEW FOR 2014!

DSA specificaiton now includes a maximum plasticity index of 6. (As per SCC board approval at their meeting on 3/11/14, a maximum Plasticity Index (PI) of 6 was added to the DSA specification. ) - Designed to limit the amount of clay in DSA


What is Plasticity Index?

The plasticity index is the range of water contents where the fines in DSA exhibit plastic properties.

- Think modelling clay

- Not all soils exhibit plastic properties -especially rock fines (this is why DSA fines must be crushed rock.)


Why a maximum PI of 6? - A PI of 6 does not mean 6% clay!!

- A PI of 6 means that the DSA most likely

contains “some” clay. - A PI of 0 or NP means that the DSA most

likely contains little or no clay.


Why a maximum PI of 6? - In general, the lower the PI value, the better

the DSA.

- The max. PI of 6 takes into account the difficulty some quarries have in producing DSA

- If we made the max. PI lower than 6, very few quarries could make DSA and the price would increase drastically.

This required test can be paid for with grant money:

Plasticity Index - Standard and accepted methodology for determining clay

content of an aggregate

- Determine Plasticity Index pre-project to determine DSA quality. (estimated cost $100)





DSA SPEC: LA abrasion of less than 40%

“The harder an aggregate is, the less likely it is to break down under traffic and erosion”

DSA Hardness:

?

DSA ESMPs Specification Details Hardness

LA abrasion of less than 40% LA abrasion test -Aggregate is placed in steel drum with steel spheres and rotated.

- Results are expressed as % loss Lower % = less crushing = harder aggregate

DSA Hardness: DSA ESMPs Specification Details

Hardness




“Aggregate MUST be delivered at optimum moisture”

WHY?

-Reduces segregation during transport and placement

- Allows for maximum compaction

DSA Moisture:

DSA ESMPs Specification Details Moisture

“Aggregate MUST be delivered at optimum moisture” DSA Moisture:

Optimum Moisture: A range of moisture at which an aggregate will achieve maximum compaction.


DSA Moisture: Standard Proctor Analysis

co

mpa

ctio

n

moisture

TOO DRY

TOO WET

JUST RIGHT

0

DSA ESMPs Specification Details Moisture Test

This recommended test can be paid with grant money:

Standard Proctor Analysis - Standard and accepted test to determine optimum

moisture for an aggregate

- Determine optimum moisture pre-project for maximum compaction. (estimated cost $150)

- Use gauge in field during placement to determine: - actual moisture compared to optimum moisture - the highest compaction (estimated cost $50/hr)


- Use nuclear density gauge in field during placement to determine:

- actual moisture compared to optimum moisture

- Determines number of roller passes for maximum compaction


DSA Moisture field “test”

TOO DRY Unable to make ball. Aggregate falls apart.

JUST RIGHT!

Aggregate forms tight ball that stays together.

TOO WET Aggregate forms wet, mushy unstable ball.

DSA Moisture: Field test

Close, but a little dry.


Cover the trucks!

DSA moisture:

Aggregate trucks MUST be covered to avoid excessive drying of aggregate.





Proper pH

• DSA SPEC: pH between 6 and 12.45 • Traditional Aggregates: No spec

DSA ESMPs Specification Details pH

Visit the Quarry

Recommended two weeks before job.

DSA ESMPs Purchasing

Visit the Quarry

The Lab Technician is your point of contact. They are in charge of quality control.


Visit the Quarry: check parent material DSA DSA ESMPs Purchasing

Visit the Quarry: adding moisture

Add water and mix for optimum moisture.


Visit the Quarry: Check the pile Aggregate separation on a pile is normal. The pile should be cut and mixed to avoid inconsistencies.

Coarse material on outside

Finer material inside


Visit the Quarry: mix the pile if necessary Aggregate separation on a pile is normal. The pile should be cut and mixed to avoid inconsistencies.


Visit the Quarry: check DSA for consistency DSA ESMPs Purchasing

Visit the Quarry

Now is the time to collect sample for independent analysis.


Visit the Quarry: establish a relationship

You will get a much better product if you establish a relationship with the quarry!


Copy of certification on handout table

FRONT


Plasticity Index

SCC Certification A certification is REQUIRED

-for each job. -anytime the source material changes.

-MUST be collected by project manager with first load of DSA delivered.

-Certification applies to source pile of aggregate, not the quarry as a whole.

-Defensible

Copy of certification on handout table

BACK


Plasticity Index < 6

SCC Certification Complete certification includes DSA specification on back of page.

Documents

Center for Dirt and Gravel Roads DSA Clearinghouse · PDF fileWe just ask that, at a minimum, you report your DSA placements to us and share any lab data you may have for the material