Optimizing Type 1L Cement with MCE and Pavix

The use of Type 1L cement is a significant step toward more sustainable infrastructure. Its production reduces CO₂ emissions compared to traditional portland cement and its use is now approved by all 50 state departments of transportation. Yet this progress has introduced significant jobsite challenges and performance issues in finished concrete. Fortunately, innovative technologies like Chem-Crete® MCE™ and Pavix® offer powerful solutions to unlock the full potential of low-carbon concrete. 

While Type 1L cement helps lower the carbon footprint of construction, its adoption has been linked to reduced strength durability and workability. Issues include slower early strength gain, increased water demand and a higher susceptibility to freeze/thaw damage. These challenges can compromise the long-term integrity of concrete structures, potentially offsetting the initial environmental benefits with the need for more frequent repairs and replacements. Chem-Crete’s advanced admixture, MCE, and penetrating sealer, Pavix, directly address these performance gaps. 

The challenges with Type 1L Cement 

The shift to portland-limestone cement (PLC) or Type 1L has been rapid. Consumption has grown more than tenfold since 2021, now accounting for over 60% of total cement used in the U.S. While its environmental advantages are clear, the practical implications are complex.

Jobsite crews have reported that mixtures with Type 1L cement often require more water and, without diligent mix design and finishing practice protocols, defects such as paste voids, blisters and scaling can occur. Achieving consistent workability and finishability can be difficult. The cement's altered chemistry can also cause compatibility issues with traditional admixtures, requiring extensive recalibration and testing. In its hardened state, concrete made with Type 1L cement can be vulnerable to excessive shrinkage cracking and discoloration. Its increased permeability makes it particularly susceptible to surface damage from freeze/thaw cycles and deicing salts—a critical concern for infrastructure in colder climates. 

MCE: A multi-crystalline admixture for superior durability 

Chem-Crete MCE is a multi-crystalline concrete admixture engineered to enhance performance from within. Added during batching, this ASTM C494 Type S admixture is fully compatible with Type 1L cement. It works in conjunction with 1L cements by forming a dense internal crystalline network that minimizes porosity and protects against moisture in liquid, vapor and ice forms.

MCE’s benefits include: 

• Internal waterproofing and protection: MCE’s primary function is to create a robust crystalline structure within the concrete matrix. This network blocks interconnected capillary pathways, impeding moisture migration. By minimizing porosity, MCE provides integral waterproofing and shields the concrete from common deterioration mechanisms. 

• Enhanced freeze/thaw resistance: The internal barrier and minimized capillary pathways created by MCE are exceptionally effective in keeping water out and insulating concrete against rapid temperature changes. These structural changes help maintain internal temperatures above critical thresholds even in sub-zero environments. This protects fresh concrete from damage during curing and ensures consistent strength development. Rigorous ASTM C666 testing shows MCE can reduce mass loss in freeze/thaw cycles by an impressive 91.6%. 

• Improved strength and hydration: MCE facilitates a more complete and efficient cement particle reaction, which has proven beneficial with the 1L cements. This improved hydration process results in a denser microstructure, leading to higher compressive strength and improved load-bearing capacity. Structures benefit from greater structural integrity and resilience to mechanical stresses. 

• Increased chloride protection: For infrastructure exposed to deicing salts or acetates, MCE provides critical resistance to negatively impacting chloride ion and chemical intrusion. Its internal barrier significantly impedes the ingress of chlorides, preventing reinforcement corrosion and extending the lifespan of concrete structures. 

Pavix: A dual-crystalline penetrating sealer 

Pavix is a unique patented dual-crystalline penetrating sealer that provides superior protection for on-grade concrete substrates. Unlike coatings that form a surface layer or products that require residual chemicals in which to react, Pavix penetrates the concrete to create a sub-surface barrier. Its dual-action technology combines pore-blocking and pore-lining crystals to deliver exceptional moisture and salt protection.



Pavix offers the following benefits: 

• Dual-action crystalline technology: Pavix’s innovative formula creates an expansive crystalline network that intercepts and blocks pathways from moisture migration. This dual-crystalline structure provides comprehensive protection against water, vapor and ice. 

• Delayed saturation and water release: Research from Iowa State University’s Institute for Transportation found that sealers like Pavix decrease initial water absorption and delay the time it takes for concrete to reach critical saturation. This is vital for reducing freeze/thaw damage and oversaturation in PCC pavements and jointing. The technology also facilitates superior desorption properties, allowing the concrete to dry out and reduce internal moisture levels faster. 



• Surface frost and freezing delay: This is achieved with standard applications of Pavix. Lab testing, using brine, resulted in a minimum 30% delay in frost and up to a 60% delay in freezing with a Pavix-treated surface. 

The effectiveness of MCE and/or Pavix is not just theoretical. These technologies have been successfully deployed in demanding real-world applications, delivering measurable improvements in concrete performance. 

Engineers for a two-mile stretch of County Highway P48 in Dallas County, Iowa, specified a multi-crystalline admixture to combat premature joint failure from de-icing chlorides. By adding MCE at one percent of the cementitious volume, the project team created a pavement that is more resilient to ice adhesion and requires less de-icing brine. The concrete also exhibited increased strength, reaching 3600 psi in just seven days. 

Another case study involving a lateral slide bridge constructed over the Chariton River on Iowa Highway 5 in Centerville, Iowa, served as a large-scale field trial for a combination of MCE and Pavix. The concrete mixture was dosed at two percent MCE with Pavix applied on the surface. Independent lab testing and evaluation by the Iowa Department of Transportation (IDOT) confirmed notable improvements in compressive, flexural and tensile strengths. The finished road showed no surface cracking or distress after construction, effectively mitigating these Type 1L cement-associated issues. 



The widespread adoption of lower-carbon cements is crucial for reducing the environmental impact of the construction industry. However, sustainability cannot come at the expense of durability. If structures built with Type 1L cement are less durable, they will require more repairs and replacements, each with its own carbon footprint. 

Chem-Crete MCE and Pavix offer a clear path forward. These advanced crystalline technologies are specifically formulated to address the challenges of Type 1L cement. By enhancing strength, durability and workability, they ensure that concrete structures are not only more sustainable, but also stronger and longer lasting. Designers, engineers and contractors should explore these innovative solutions to ensure project performance from start to finish. Reach out to ICC Distribution today to learn more.  

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