RSP Samples 2012

Today Caltrans sent out a request for revised RSP Questionnaires so that they know what tests your laboratory is certified for.  If you did not get an email you should contact the Reference Sample Program at caltrans_reference_sample_program@dot.ca.gov.

Their email also let us know that they plan on sending out RSP samples in May and October of 2012.

Cold-In-Place Recycling Round 2

I recently had the opportunity to go out to a couple different types of cold-in-place recycling (CIR) jobs.  The first job was using the emulsion process that I spoke about here.  The second job was an eye opener for me in terms of cold-in-place recycling because it was a very different process than the emulsion process that I had learned about previously.  FMG (Fonseca/McElroy Grinding) out of San Jose, CA runs a recycling train that uses a foamed asphalt to create a recycled road surface instead of emulsifiers.

     

As the first step, a layer of cement is laid down on the surface of the roadway. As the train moves along the roadway it grinds up the roadway, picking up the cement along with it.  A traditional milling drum rotates upwards which can cause slabs and the need for additional crushing in the recycling process.  FMG's milling drum rotates in the downward direction which gives them more control over the size of material that is produced.  Once the road is ground, the foamed binder is added to the material.  The foamed binder is created by injecting water and air into the asphalt bitumen.  The foamed asphalt, and any additional water necessary to achieve the optimum moisture of the mixture are mixed with the grindings and then laid down on the roadway to be compacted with rollers.  

The mix design for this type of asphalt is created by taking samples at various locations on the roadway before CIR Work.  These samples are taken by a small grinder and processed into a product to duplicate the aggregate material produced by the milling machine.  The laboratory has a special foaming machine that can duplicate the foaming bitumen process that the recycling machine has in the field and the foamed bitumen is added to the aggregate material by mixing just like in the field.  This type of mix design is not done using the HVEEM or Superpave method but uses the tensile strength test, similar to the Marshall method.  

With emulsified cold-in-place recycling the material initially comes out of the recycling machine looking like brand new HMA from a traditional hot plant (albeit brown at first).  With the foamed asphalt cold-in-place recycling the material looks more like a recycled base rock as you can see in the photo below.      

Foamed asphalt Cold-in-Place material immediately after being laid down

Close up of foamed asphalt Cold-in-Place material immediately after being laid down

The reason behind this difference in initial appearance is that with emulsified cold-in-place asphalt, the binder coats the rocks.  With foamed bitumen cold-in-place asphalt, the binder forms a sort of web which does not completely coat the rock but still holds the particles together.

After being laid down, the material is subjected to 3-4 steel drum rollers and a rubber tire roller.  After compaction, the roadway looks very much like a roadway made from traditional HMA and is traditionally fog sealed for extra protection from the elements.  Currently it is customary for these types of roadways to be overlaid with a traditional HMA or another type of wear course within 3 days but traffic is put back on the road at the end of the shift or even earlier.  

Foamed asphalt Cold-in-Place recycling roadway after compaction

The entire process was extremely humbling to watch and impressive to say the least.  This type of train is much shorter than the train I mentioned in my last post and does not have the same issues of having difficulty turning around or taking curves in the roadway.  This type of recycling seems to be a good, low cost replacement for a full depth or multi-layer paving project.  Unlike the emulsified recycled asphalt pavements, an overlay is typically recommended within 3 days of paving with a foamed bitumen cold-in-place recycled pavement layer.  It will create a very stable and cohesive sub-layer to an overlay but is not typically recommended as the surface layer since the elements can cause it to ravel.  In addition, this type of paving, like the emulsified cold-in-place recycling process is not recommended for roads with subbase failure.  This process works best for roads with surface pavement problems.

With that said, as I mentioned before I can definitely see cold-in-place recycling as the next big thing in California.  Both the emulsified and foamed bitumen cold-in-place recycling processes are great options for cities and counties who have tight budgets, high traffic areas, and/or a desire to reduce pollution by reducing fumes and trucking.  Take a look into it the next time you're bidding a job, you might be surprised at the money you can save!

Win the 2010 Caltrans Standard Specs!

This website was originally created to serve as a resource for those of you out there who need more information about the ins and outs of the construction industry.  In pursuit of that we've just added a discussion forum to our website.  You can access it by clicking on the tab above that says "Discussion Forum".  Here you can ask any questions that you have about the industry and also share your expertise to help out someone else.

As an added incentive and to commemorate the release of the 2010 Caltrans Standard Specifications book, we'll be giving a free copy to the first person to write 40 relevant posts.  Good luck!   

It could be yours!  Get posting!

They're here!

We just got our paper copies of the Caltrans Standard Specifications and boy are they big!  They're $30 off of the Caltrans website here.  Happy Reading!

CALCIMA Speaks For The Industry On Poor Test Turnaround Times

If you've ever worked with Caltrans on a construction project, either as a contractor or supplier you've no doubt had at least one experience where you have had poor turn around time on the QA test results from Caltrans.  Although this is not always the case, Caltrans has set a reputation for itself of returning test results to the contractor weeks or months after the date of paving.  In some cases, contractors don't receive the test results until well after the job has been completed, if at all.

Many industry associations and businesses have addressed this issue with Caltrans at various levels and it looks like this time CALCIMA is taking a stab at it.  In a letter to Malcolm Dougherty, Acting Director of Caltrans, CALCIMA points out the issue, explains why it is detrimental to contractors, and offers several realistic solutions.  The letter in its entirety can be found here.

Many of the solutions offered in the letter are actually things that Caltrans is currently looking into and moving towards in the future.  Among these are having all Caltrans labs accredited by AASHTO and having an independent 3rd party certify Caltrans and Industry laboratories.  As I have mentioned before, I also believe that these steps will do a world of good for the Industry and Caltrans alike.  Another solution that is offered to Caltrans is having an independent laboratory perform the QA testing.  This has been suggested by many people over the years and it is still a bit murky as to why this is not a feasible solution to Caltrans.  In 2010 the District 4 Caltrans lab completed over 160 mix designs and verifications.  For those of you who have not been directly involved with a mix designing process let me tell you that if everything goes right on the first try (which it often does not), you are looking at 4-5 full days of testing for one person which means that in 2010 District 4 dedicated over 6400 man hours to mix designs and verifications.  Now take a step back and realize that these are JUST mix designs and verifications.  This doesn't include transferring the samples to the lab, field inspections, plant inspections, daily QC/QA testing, or the hundreds of other various tests that their lab performs throughout the year.  When you really look at it, there's no wonder why Caltrans has issues with making a 48 hour turnaround deadline.  Especially when you factor in the state budget cuts and furloughs.  I personally do not blame the Caltrans laboratory for not being able to make the specified turnaround because I know how impossible that quantity of testing can be for a lab.  What I am confused about is why Caltrans has not agreed to sub out some of their work to obtain the turnaround time that they've put in their own specifications.  Caltrans has made a huge push over the last year towards partnering with contractors so that an issue can be resolved at the time of construction instead of after the fact in dispute resolution.  Subbing out some of their lab work to 3rd party laboratories would undeniably help with this initiative and in the larger scheme of things create some much needed jobs for the construction industry.

In pursuit of this partnering Caltrans could also benefit from CALCIMA's last suggestion which is to allow 3rd party labs and contractors to come to the Caltrans labs to view how they are performing the test methods.  This  type of behavior seems to vary from district to district but some Caltrans labs do not allow any outsiders to view them testing.  This is completely contrary to Caltrans' partnering initiative.  There are probably a plethora of reasons as to why those districts refuse to allow people in their labs but the biggest reason that they should is that there are many test methods that have a lot of grey area.  These test methods allow for a technician to make a decision based on his experience with the test and many of these decisions are visual.  As a technician teaches another technician the test, and that technician teaches another person, the tricks and reasoning behind how and why to do the test exactly as it was done when it was created can diminish.  Being able to work with the Caltrans lab and see how they are performing the test will give 3rd party laboratories an opportunity to correct any differences between how each lab runs the test and reduce disputes in the future when the test results do not match.  It is easy for us to say that Caltrans doesn't know what they are doing but to be honest, I would assume that many of us make similar "mistakes" all of the time.  Having a pre-job refresher with the Caltrans lab would allow both labs to correct themselves if necessary.

It's nice to see the industry coming together as one unit to offer solutions to Caltrans and other owner entities.  Working towards change is always a long curvy road with a ton of speed bumps but we're getting better at navigating through it all now and it is only a matter of time until the Caltrans partnering initiative really comes to fruition.