Colorado Public Works Journal, Summer 2022

UPDATES Works News Portland Limestone Cement Every cement supplier will be ceasing production of ASTM C150 Type I/II cements this year and replacing them with ASTM C595 Type IL cements. This is part of the cement industries push for carbon neutrality. CDOT has been using Type IL cements since 2006 in our pavements, but the ready mixed side has not due to building codes and architects unwilling to update their specifications. Due to recent changes in building codes, the architects are being forced to update their specifications Subsection 601.05 states (in part): The Contractor shall submit a new Concrete Mix Design Report meeting the above requirements when a change occurs in the source, type, or proportions of cement, slag cement, fly ash, high-reactivity pozzolan, silica fume, or aggregate. This will affect CDOT projects once the ready mixed concrete supplier can no longer obtain Type I/II cement and will be required to use Type IL cement. Per CDOT specifications, a change in cement source or type requires a new mix design which takes a minimum of 28-days plus for review. The cost of a typical trial mix is $5,000-$9,000. Type IL cement and Type I/II cement are very similar. Type I/II cement is a clinker that is ground with up to 5% limestone and represents about 3-4% in the Colorado market. Type IL cement uses the same clinker but is ground with 5-15% limestone. The Type IL cements in Colorado typically have 10-12% limestone. The cement companies determined how much limestone to use based on performance. These companies have determined that the Type IL cements with 10-12% limestone perform similarly to the existing Type I/II cements in workability, strength gain and ultimate strength. CDOT Materials has met with industry representatives and have approved the following transition plan through the Materials Advisory Committee, to minimize the impact on projects statewide: 1. All Concrete mix designs on the CDOT Approved products list set to expire in 2022 will be extended to December 31, 2022, if they are using an ASTM C150 cement. 2. ASTM C595 Type IL cement from the same source can be swapped pound-for-pound with ASTM C150 cements on approved mixes provided the following conditions are met: a) If the mix design aggregate has been determined to be alkali-silica reactive (ASR) through ASTM C1260 (a mix design requirement) then the ASR mitigative measures with the new Type IL cement must be tested and pass per ASTM C1567. b) The sulfate resistance requirements in Subsection 601.04 have been met for the sulfate resistance class on your Project. 3. Concrete mix designs that make a change to Type IL cement will expire at their natural expiration date after December 31, 2022. 4. Concrete mix designs expiring after December 31, 2022, will require a new mix design upon expiring if they have not already changed over to Type IL cement. If a Contractor needs to make the mix change involving Type I/II and IL cement, the PE/PM should contact the Concrete & Physical properties lab at dot_concretemixdesigns@state.co.us to have your existing mix design(s) reviewed and re-issued with the new cement type. On Projects with concrete pavement, a new process for strength will be created when the change is made. Questions can be addressed by Staff Materials Lab or Region Materials Engineer. Summer 2022 | 11 CCA Awarded Planning Grant CCA Awarded Planning Grant to Create New Civil Construction Bootcamp for Young People Interested in a Career in Construction. CCA has been awarded a planning grant to fund, over the next four weeks, the creation of a Civil Construction Bootcamp that will prepare participants for careers in the construction industry. The Civil Construction Bootcamp will provide training to participants to increase their readiness to work and provide them with several industry-recognized credentials that employers highly value in new hires within the construction industry. The Civil Construction Bootcamp is a four-week training course tailored for Coloradoans who are interested in entering the civil construction industry. The training courses will be offered in areas covering all of Colorado, as well as through a virtual learning format, to provide geographic equity across the state. The Civil Construction Bootcamp course will utilize a nationally recognized curriculum created by the National Center for Construction Education and Research (NCCER). The NCCER provides a highly recognized standard in a multitude of construction skilled trades curriculum and instruction. Much of the NCCER's core curriculum will be the key focus of the coursework. This will include instruction in basic safety, construction math, hand and power tools, construction drawings, material handling, employability skills and more. Civil construction activities will be emphasized to better prepare attendees for the rigors of the unique environment of underground utility installation, asphalt and concrete paving, reinforcing and structural ironwork, bridge construction, and roadway/work zone safety. Once CCA successfully completes the four-week planning period, the next step will be awarding the remainder of the grant that will fund the program over the next 12-24 months. Watch for more information as CCA moves forward with this innovative and exciting new program to help fill the workforce gap for CCA members! Metro Water Recovery Expands Fort Lupton is Metro Water Recovery’s newest member connector since the City of Brighton and South Adams County joined the organization in July 2009. “Positioning Fort Lupton for the future, our inclusion with Metro is a positive move for our citizens and businesses. Metro’s voice when dealing with Colorado’s regulatory agencies is far better heard than ours alone,” said Mayor Zo Stieber-Hubbard. Metro will accept Fort Lupton’s flows at its Northern Treatment Plant in Brighton no later than December 31, 2025, with the option to extend the connection by one year to December 2026. The agreement was signed on June 7, 2022. Metro’s service area now extends to the north of Brighton and straddles both sides of U.S. 85. Meet Metro’s Newest Member Connector Anchored along the South Platte River and established as a trading post in 1836, the City of Fort Lupton has served an important role in Colorado’s history for nearly 200 years. With a population of 7,995 (2020 census), Fort Lupton maintains a small-town atmosphere with a high quality of life within commuting distance to larger population centers – including Greeley, Denver, and Fort Collins.

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