Navigating the Shift to Type 1L Concrete: Curecrete’s Expert Advice for Concrete Flooring Contractors/Applicators


Curecrete’s Type 1L Resource Page
Up to date news, insights and recommendations designed specifically for applicators, general contractors and architects.


As the concrete industry undergoes a significant shift with the adoption of Type 1L concrete, it is imperative for concrete flooring professionals to equip themselves with the knowledge and strategies to navigate this shift successfully. In response to this evolving landscape, Curecrete Distribution, Inc. is pleased to provide information and resources that delves into the intricacies of Type 1L concrete, offering valuable insights and practical recommendations for flooring contractors/applicators, architects, and general contractors.  

Type 1L concrete is concrete that contains Type 1L cement, also known as Portland Lime Cement (PLC). This cement is made from limestone, silica, iron ore, and clay, which are processed in a rotating kiln to produce clinker. The clinker is then cooled and ground, often with a maximum addition of 5% gypsum. 

This process of creating clinker heavily relies on fossil fuels and is a major contributor to CO2 emissions. To mitigate this, cement manufacturers are substituting 10-15% of the clinker with crushed, unfired limestone fines to create Type 1L cement, reducing CO2 in the process. 

Aerial view of cement production facility with emissions being released from 3 chimneys.
Concrete is estimated to account for 7-8% of the world’s carbon output, and is a focal point for reduction efforts.

Type 1L cement aims to reduce the CO2 output during cement manufacturing. This initiative arises from the Paris Climate Accords of 2015, with the United States agreeing to become carbon neutral by 2050, with some individual states aiming for 2045. Currently, the U.S. is less than 15% of the way there. Given that concrete is estimated to account for 7-8% of the world’s carbon output, it has become a focal point for reduction efforts.  Currently, the United States is the fifth largest cement producer, contributing approximately 1.5-2% of the global carbon output from cement production. 

As a result, many cement producers are exclusively shifting away from traditional OPC production in favor of Type 1L cement. This transition is not only driven by environmental regulations, but also by the increasing commitment of large corporations to lower their global carbon footprint. As cement producers exhaust their OPC supplies, Type 1L cement is becoming more widespread. Ready-mix concrete producers are also embracing this environmentally-conscious shift. Ultimately, traditional OPC will phase out, making Type 1L cement the industry standard. 

Type 1L concrete presents a range of opportunities and challenges for concrete flooring contractors/architects and related trades, general contractors, and architects. Understanding its impact on setting times, workability, and surface characteristics is essential for maintaining quality results and optimizing project outcomes across various applications.  

While cement manufacturers assert that Type 1L concrete is a 1 to 1 exchange, and thus exhibits no measurable differences from OPC, flooring contractors/applicators are sounding the alarm, stating otherwise as they encounter concerning differences. Areas of significant concerns are softer surfaces, increased cracking, increased water demand, variable set times, top surface cracking, and open, porous surfaces, to name a few.  

For flooring contractors/applicators, these concerns could translate into project delays, elevated costs in both labor and materials, and difficulties in meeting customer expectations, particularly regarding the uncertainty surrounding Type 1L concrete’s aesthetic qualities. 

“As a direct result of these concerns, industry professionals are increasingly seeking resources and guidance to navigate the nuances of Type 1L concrete,” noted Roy Bowman, Vice President of Product Engineering and Support at Curecrete. “Our resources on Type 1L concrete aim to empower industry professionals with the tools and strategies needed to embrace Type 1L concrete effectively,” he continued. “By providing actionable insights and best practices, we are helping concrete flooring professionals stay ahead of the curve and achieve success in this changing landscape.”  

Concrete flooring applicator wearing fluorescent yellow sweater, white hard hat, and safety goggles holding a hose and spraying Ashford Formula densifier on the concrete floor; blue Ashford Formula drum out of focus in the background.
Ashford Formula and RetroPlate still deliver their trademark hardening, dustproofing and optimal performance benefits on Type 1L concrete.

Yes! Ashford Formula and RetroPlate are effective and work well on Type 1L concrete surfaces. This has been confirmed in a series of tests, including third-party, long-term testing of cores sent for petrography.  

NOTE: Flooring contractors/applicators should thoroughly assess and comprehend the characteristics of the floor, as adjustments to application techniques may be necessary to achieve comparable densification benefits to those typically observed with OPC. 

Close up of Mohs pencil hardness test being performed on Type 1L concrete floor.
Testing the concrete surface for hardness before and after densification ensures the process’s effectiveness.

To ensure effective densification with Type 1L concrete, test the floor surface hardness before and after densification using a Mohs pencil hardness test. It is also important that flooring contractors/applicators possess a thorough understanding of the slab they are working with and can recognize and address any potential issues that may arise. Potential conditions include:

  • Premature gelling of the densifier; and 
  • “Thirstier” slab due to high porosity, increasing the amount of densifier used.

Should these challenges arise, flooring contractors/applicators can proactively plan for and mitigate these challenges. 

Three concrete flooring applicators with push brooms brooming the Ashford Formula liquid densifier on the floor surface in a newly constructed warehouse.
Flooring contractors/applicators are on the front lines when it comes to seeing and remedying challenges and concerns with Type 1L concrete.

There are three primary areas of concern for flooring contractors/applicators:   

  1. Pre-Placement Considerations 
    Discuss known common problems associated with Type 1L concrete early and often. Understand the mix design, prepare for potential challenges, and document key aspects for successful project execution. 
  2. Post-Placement Considerations 
    Once flooring contractors/applicators are ready to begin work, it is crucial to inspect the floor thoroughly, documenting and evaluating any deficiencies or concerns related to floor finish, softness, appearance, or the condition of the concrete. Share this documentation with the general contractor and other project stakeholders and ask for their buyoff once they are made aware of the concerns. This step is essential to ensure that everyone is in alignment and agreement. 
  3.  Finished Aesthetics Considerations
    Addressing finished aesthetics is critical to managing expectations. Identify all deficiencies that can impact the aesthetic quality of the floor and its long-term durability. Clarify what can and cannot be corrected before work commences. For polished concrete jobs, Curecrete recommends performing a mockup, and for densified floors, highlighting aesthetic issues early on is key.
general contractors
  1. Thorough Planning & Collaboration
    General Contractors should start with detailed planning, understanding Type 1L concrete’s requirements and potential challenges, and collaborate closely with all project stakeholders.
  2. Quality Control & Floor Protection
    Emphasizing strict quality control and documentation of mix designs is crucial to achieving desired outcomes with Type 1L concrete. It is imperative to effectively manage the temperature during the placement and curing process and ensure adequate floor surface protection measures are in place. Type 1L concrete tends to have a softer, more porous surface, making it more susceptible to scratches, staining, and other forms of damage. 
  3. Education & Communication
    Ensure all stakeholders become well-versed in Type 1L concrete’s properties. Maintain open communication between all parties as it is critical to proactively addressing challenges effectively. 
architects
  1. Transparent Mix Design Documentation
    Encourage transparent mix design documentation as it is a critical tool for enhancing collaboration, ensuring accountability, and facilitating informed decision-making among all project stakeholders.  
  2. Revised Product Application Methods
    Be aware that certain concrete trades may need to adapt their standard application methods to ensure proper performance and compatibility of their products with Type 1L concrete. 
  3. Extended Time Frames & Added Costs
    Anticipate the likelihood of extended time frames and additional costs arising from trades needing to adjust their application practices to achieve accepted results for concrete.

    NOTE: Curecrete offers an AIA presentation focusing on Type 1L concrete, open to all architects in pursuit of continuing education credits. For further details, please click here.

As the world increasingly pivots towards sustainable practices, Curecrete actively embraces the transition to Type 1L concrete and doing our part. Despite the uncertainties inherent in this shift, we continuously commit to learning, adapting, and sharing knowledge.

Our goal is not only to develop innovative solutions for the challenges posed by Type 1L concrete, but also to empower industry professionals to navigate these complexities with confidence. We trust these resources will assist concrete professionals in achieving successful, high-quality projects and ensuring ongoing customer satisfaction.