What's New with ISSA Technical Director Bob Jerman- July 2022

The dog days of summer are definitely upon us here in Charleston, as well across much of the globe.  If you’re fortunate enough to live in an area where the temperatures and humidity are more moderate, consider yourself blessed.   Based on the content of inquiries coming into the “Ask an Expert” link on the ISSA website and conversations with other industry professionals, business is extremely expensive this year and full of multiple, non-traditional challenges faced by everyone. 

One of those challenges comes from the changes occurring in the cement industry.  All industries, including ours, have ongoing pressures to decrease their carbon footprint and improve their sustainability.   By design, pavement preservation is fundamentally sustainable.  That said, we continue to search for ways to improve upon its sustainability.  One way that the cement industry is addressing the issue of sustainability is by replacing ordinary Portland cement (PCC) with Portland Limestone cement (PLC).  You may, or may not, be aware of this in your area.   It’s important that you are informed as this change is already underway in many areas and will be coming to your area, if not there yet.  Our focus is on Type I and Type II (or Type I/II) Portland Cement as it is being replaced by Type IL Portland Limestone cement.  The cement industry claims that it is a direct substitute for ordinary Portland cement, providing the same performance in concrete applications but with a carbon footprint that is ~10% lower in carbon emissions.  Ordinary Portland cement (used in our pavement preservation industry for decades) typically contains up to 5% limestone whereas the Portland Limestone cement limits are 5-15% limestone.  As always, it is critical that your mix design evaluations be performed with the same cement that will be used in the actual project application in the field.

So, what does this mean for our industry?  Hopefully, nothing significant.  At this time, we don’t have enough information to answer the question fully.  Initial feedback is that the Type IL PLC performs very similarly to traditional PCC Type I/II.   Again, this is very, very early in our investigation on the impact of PLC on our slurry surfacing (slurry seal and micro surfacing) systems.   We’ll be collecting data from many of you over the next few months.  If you’ve performed laboratory evaluations or your company has used the new Type IL PLC in the field, please reach out to me and share that information.  When is this change coming?  My research indicates that it’s already happened in some regions, is beginning to transition in others, and is yet to be introduced at all in other parts of the world.  At this point, all indications are that ordinary PCC is becoming increasingly difficult to find in some areas and may not be available by the end of 2023 or beginning of 2024.  Our goal here is to keep you informed and work together as an industry to integrate this changing composition of one of our raw materials into our systems with minimal impact on performance.

Our second “ISSA Forum” call will take place on Wednesday, July 20^th from 1:00-2:00 pm EDT.  If you weren’t able to attend the first one earlier this year, please consider attending and contributing to our second call next week. As always, please don’t hesitate to reach out to us with ideas and/or questions.

"Every day is a gift!  Never take a single one for granted!"

Sincerely,

Bob Jerman

ISSA Technical Director