15 Asphalt & Manufacturing

ASPHALT &

MANUFACTURING

A message from Mickey Cox, General Manager of Asphalt Plants

ver this past year, there have been changes at O the manufacturing facilities to facilitate continued improvement and lead Ajax into the future. • All plant load out systems were upgraded to the Apex System allowing us to remain competitive and add new technologies such as E-ticketing as well as other technologies as they become available. • Plant 1, North Venice - three new silos were added, along with an AC tank and one of the virgin cold feed bins being replaced. • Plant 2, Punta Gorda – the existing 7 cold feed bin system was replaced in its entirety along with a new hot oil heater. • Plant 3, Palmetto - the Palmetto shop was remodled and converted into an inventory control room to store parts for all manufacturing facilities, a new lime silo was erected, the lab trailer was remodeled, and we will be installing a replacement hot oil heater in 2020. • Plant 4, Fort Myers - three additional silos will be erected and a new lab/storage building constructed in 2020. • Plant 6, Tampa - three new storage silos were erected.   The above changes have allowed the plants to be more flexible, increase production and better meet customer’s expectations.

Along with equipment upgrades and improvements, there have been some personnel changes.

IMPROVEMENTS INCLUDE: PROMOTIONS:

• Shane Williamson was promoted to the Northern

Regional Plant Manager in July of 2019. Shane was previously a lab technician at our Fort Myers facility. Shane is doing a great job meeting the needs and expectations of the position. • Cody McEwen has stepped into the role of plant foreman at the North Venice facility. • Tampa plant foreman Greg Hogue transferred to the Odessa facility to replace Rickey Stevens that retired in December of 2019. • Arnold Salinas was promoted from plant operator to plant foreman at the Tampa facility.

Congratulations A-Team!

  I would personally like to thank all plant employees that work hard every day and step up when needed so that we can continually meet our customers’ needs and expectations. I would also like to acknowledge our asphalt facility mechanics and electricians that work, night and day, and are critical in keeping our plants running. Each plant employee performs a vital role in the success of the plants and in turn Ajax Paving.

T he adoption of a cracking test for approval of asphalt mixes in the state of Florida seems to be getting closer each day. With this prospect in mind, a task group was formed by Association of Asphalt Contractors Association of Florida (ACAF) in late 2019 to analyze the implementation of one of the newer cracking tests, the IDEAL-CT.

The IDEAL-CT is a cracking test that has shown great potential to predict cracking resistance. It was developed by Fujie Zhou at the Texas A&M Transportation Institute. The IDEAL-CT test is currently being supported by large sectors of the asphalt research community. Its main advantages are that sample preparation is simple, it is highly repeatable, and it has a reduced testing time.

 Having one of only three labs in the state with this testing capability, Ajax was one of the main participants of the Task Group. The other two labs that perform IDEAL-CT tests in Florida are Asphalt Testing Solutions, and the FDOT State Materials Office. All three labs have done IDEAL-CT tests on mix samples provided by contractors from all over the state. The main focus of this project is to determine lab variabilities, analyze how current DOT mixes perform on this test, and finally make a recommendation on testing requirements if this test is ultimately adopted by FDOT.

Written by Alfredo Castro QC Engineer

Articles on pages 14-15 Written by Alfredo Castro, QC Engineer

In2019, the Federal Aviation Administration (FAA) incorporated an important new testing requirement for all of their P-401 asphalt mixes. Asphalt mixes used in FAA runways should now be tested on an Asphalt Pavement Analyzer (APA). This test determines the resistance to rutting of an asphalt mix.

This new requirement was implemented to identify mixes that will have a good rutting performance under the severe loading conditions imposed by heavy aircrafts. As one of only few contractors in the state with APA testing capabilities, Ajax has conducted APA testing for all of their P-401 designs in-house.

The APA is a wheel tracking test that consists of applying wheel loads on a set of asphalt samples compacted to 7% air voids. The load is applied by metal concave wheels sitting on a pressurized rubber hose that are inflated to a specified air pressure. The test is also run in a closed chamber that is kept to a constant temperature, usually 64 °C. This is meant to simulate the loads made by wheels of a truck or a heavy vehicle on a pavement under the most severe circumstances. A maximum allowable rutting for the testing samples is specified at 4,000 or 8,000 cycles of loading. Overall testing time is usually 7.5 to 8.5 hours.

Job Photo: SR 93 I-75 S of Moccasin Wallow Road to the Hillsborough County Line in Manatee County A. P. Bolton Category - Statewide Winner

The National Center for Asphalt Technology (NCAT) is the premiere institution in asphalt research. They are one of the main driving forces in the development and implementation of new technologies in the asphalt industry. Their research facilities include their Test Track, which is a 1.7 mile high-speed, full-scale accelerated pavement testing facility.

In 2018, NCAT initiated a Round-Robin study for asphalt performance tests used in balanced mix design. Ajax was one of the over 40 labs in the country that signed up for the different tests, which included Asphalt Pavement Analyzer (APA), Hamburg, IFIT, and IDEAL-CT tests. In 2019, the first phase of the study consisted of shipping asphalt mix from the latest Test Track research cycle to the different participants to test using the different procedures. The second phase, which is currently on its final stages, consisted of sending compacted samples ready for testing.

The study has two main objectives. The first objective is to give labs a chance to compare their results to those of other labs and if necessary, make the adequate corrections to their procedures. The second objective was to generate information and data on within-lab and between-lab variability of the different tests.

Results of the first phase have been received. They showed that Ajax had great comparisson to the other labs, with a very low deviation and variability. These results from an NCAT study serve as an assurance that when Ajax conducts any in-house performance test, the results obtained should be extremely reliable.