Tennessee Concrete Conversations: Producing Durable Concrete with Portland Limestone Cement(Type 1L)

In this episode of Tennessee Concrete Conversations, TCA Executive Director Alan Sparkman dives deep into one of the most important changes in today’s concrete industry — the widespread use of Portland Limestone Cement (Type 1L). Alan breaks down what this shift means for contractors, finishers, designers, and even homeowners planning their next concrete project.

A Rapid Shift in Tennessee’s Concrete
Just a few years ago, only 2% of the cement used in Tennessee was a blended cement.
Today, 97% of all cement used to produce concrete in the state is Type 1L.

That’s an enormous transformation — and while Type 1L is an approved, high-quality material, it brings with it changes in how concrete behaves, particularly during placement and finishing.

Type 1L Cement: What You Need to Know

Type 1L (Portland Limestone Cement) can absolutely produce strong, durable concrete — but it requires careful attention to details in mix design, finishing, and curing. Alan outlines key differences and best practices, including:

Strength vs. Durability: While overall strength remains consistent, durability — not just compressive strength — should be the main focus for exterior applications.

Bleed Water and Finishing Timing: Type 1L affects how and when bleed water appears. Finishers must be careful not to work the surface too soon, and should never finish concrete while bleed water is still present.

Avoiding Surface Water: Sprinkling or misting water onto the surface during finishing weakens concrete. Instead, Alan recommends using finishing aids (such as colloidal silica-based products) — not evaporation retarders — to achieve a smooth, durable surface.

Water-Cement Ratio: The Foundation of Quality

The water-cement ratio remains one of the most critical factors in producing durable concrete.

For residential work, the maximum water-cement ratio should be 0.45, aligning with ACI recommendations.

A slump of 6–8 inches can still be achieved by using chemical admixtures (plasticizers or water reducers) rather than simply adding water.

Maintaining the proper ratio ensures both strength and long-term durability, even for driveways, patios, and sidewalks.

Residential Concrete: Finishing, Curing, and Cracking

For homeowners and contractors alike, Alan stresses a few essentials:

Finish in the right sequence. Strike off, bull float, wait for bleed water to evaporate, then proceed.

Cure every slab. Proper curing locks in moisture, ensuring concrete reaches its full strength and service life.

Plan for joints. Joints don’t make themselves — and they’re key to preventing random cracking.

Insist on a written contract. Include mix design details like 4,500 PSI strength, 0.45 max water-cement ratio, and use of water reducers.

Decorative & Colored Concrete Considerations

Colored concrete can be beautiful — but consistency depends on realistic expectations and controlled processes.

Factors like temperature, humidity, and surface water all affect final color, so contractors and clients should discuss color variation and review actual work samples before a project begins.

Choosing a Quality Contractor

Alan encourages homeowners and project owners to do their homework:

Review real past projects (not just photos online).

Ask for references and industry certifications, such as ACI Concrete Flatwork Finisher or membership in TCA, ASCC, or ACI.

Look for contractors committed to quality, education, and best practices.

Winter Maintenance Matters

Even the best concrete needs proper care. Alan warns against overusing chemical de-icers, which can damage concrete surfaces.

His tip?

“Use sand instead of de-icers when possible — it gives traction, helps your clay soil, and won’t harm your concrete.”

🔗 Learn More & Access Resources

Explore TCA’s full library of professional resources and technical guides under TCA’s Pro Resources tab on our website.

You’ll also find helpful references from ACI, including ACI 332 (Residential Code for Concrete), ACI 301, and ACI 318.

For additional questions, reach out anytime through — the TCA team is here to help you produce quality, durable concrete every time.

🎧 Listen now to the full episode of Tennessee Concrete Conversations with Alan Sparkman to learn how to get the best results with Portland Limestone Cement in every project.