What Freeze-Thaw Cycles Really Do to Your Long Island Patio (New CT Scan Research)

Long Island winter weather does something invisible the first time you see it looks like a surprise. A patio that looked fine in September 2026 now has cracking pavers, a retaining wall with crumbling mortar and a concrete slab whose surface is scaling off in flakes. The cause is the freeze–thaw cycle — water soaking into tiny pores, freezing to ice and expanding, melting and repeating — but a new 2026 study finally shows exactly what happens inside the material as that damage builds up.

What Researchers Discovered Inside the Concrete

A team led by Qixiang Xu and Gang Cheng at Tsinghua University published findings in the journal Discover Concrete and Cement that used rapid freeze–thaw laboratory testing paired with X-ray computed tomography (CT) scanning to make a hidden deterioration process visible in three dimensions.

Their CT scans revealed that initial porosity and pore volume “stood at 1.6 percent and 80.8 mm3, consisting mainly of closed spherical pores,” the paper states. That changed dramatically as cycles accumulated.

After 75 freeze–thaw cycles, “pore volume and pore ratio had increased by 14.9 percent and 50.6 percent respectively, with visible internal cracks forming around original pores.” By 100 cycles, the jump was steeper: “porosity and pore volume jumped by 45.6 percent and 124.2 percent.”

The decisive signal came from surface area. Pore surface area “increased by 82.1 percent, 263.6 percent and 411.0 percent at 75, 100 and 125 cycles” compared to the unfrozen baseline. Because the surface area growth vastly outpaced volume growth, the researchers concluded that “microcrack widening rather than pore nucleation dominates damage progression beyond 75 cycles.”

In short: most of the real damage in the middle range of tested cycles does not come from new pores forming — it comes from existing tiny cracks widening and linking up until the material structure begins to fail.

The study also put a number on force behind that widening. The “9 percent volume expansion of water-to-ice phase change” enters as pressure inside every pore, and both numerical CT simulations and physical CT observations “consistently identified the interfacial transition zone” — the weak region around aggregate particles in concrete — “as the critical damage zone.”

The deterioration was measurable. After 150 cycles, “mass loss reached 1.16 percent at 100 cycles and 4.2 percent at 150 cycles, while the relative dynamic modulus decreased to 67.64 percent at 150 cycles.” A specimen is considered fully damaged when mass loss exceeds 5 percent or the relative dynamic elastic modulus falls below 60 percent — thresholds the researchers approached but did not quite reach by cycle 150.

What This Means for a Long Island Patio or Walkway

Long Island sees enough freeze–thaw cycling each winter to drive real damage: days when temperatures swing above and below freezing. That is fewer cycles than the lab tested, but the damage mechanism is the same: water in pores, expansion on freeze, stress at the weakest points.

What the CT scans show matters for every hardscape feature on a Long Island property:

• Patios and walkways: If you are planning a new installation, patio contractors on Long Island should design the base to shed water. The interfacial transition zone is exactly where paver bases and concrete slabs are most vulnerable. Microcrack widening means small hairline cracks you see in the fall will grow through the winter — not because the freeze is deeper, but because each cycle nudges them wider.
• Retaining walls: The researchers noted that “cube specimens showed more severe peeling than prisms, because corners and edges experience freeze–thaw cycling in multiple directions with a wider temperature range.” Retaining-wall faces and caps are exactly those exposed edges on a property.
• Chimneys and brickwork: Mortar joints are interfacial zones by definition. When the ITZ weakens, bricks crack or pop loose in cold weather — a common call for masonry repair around this time each year.

The practical takeaway from the CT scans is that visible cracks in October are not cosmetic. They are the surface sign of an internal process that each freeze–thaw cycle accelerates.

Common Questions About Freeze–Thaw Damage

Is the damage done all at once during one cold snap?

No. The research shows a progressive process: pores grow slowly before accelerating once microcrack linking begins — the rate rises sharply after that turning point around cycle 75. A single freeze can open a hairline crack wider; repeated cycles are what make it structural.

Does sealed or capped concrete resist this kind of damage?

Sealing fills surface pores and slows water ingress, which is exactly what the study points to: if less water gets inside, fewer pores exist to turn into cracking space. Sealing does not eliminate the volume expansion mechanism — the “9 percent volume expansion of water-to-ice” that drives pressure — but it buys time by reducing pore saturation.

How can I tell if my masonry is beyond simple patching?

The CT scans reveal that the interfacial transition zone is the weakest link: when spalling creates exposed aggregate, mortar joints crumble between bricks or paver bases shift, and cracks run deeper than a surface layer of flakes, the ITZ itself has begun failing. At that point, patchwork rarely holds — replacement of the damaged section is the reliable fix.

Does this research apply to pavers as well as concrete?

The study tested Portland-cement concrete with basalt aggregate and river sand, which matches typical patio-base and walkway mix designs. The mechanism — freeze expansion at weak interfacial zones — applies to any cementitious material that absorbs water: mortar in brickwork, the beddings under pavers, and sound blocks used in retaining walls.

What to Do Now Before Winter Sets In

• Walk your hardscape before the first hard freeze. Look for new hairline cracks, loose or wobbly pavers and any spalling (flaking) on concrete surfaces or brick faces. Mark spots with chalk so you can watch whether they grow through a few freeze–thaw cycles.
• Clear debris from drainage paths around patios and retaining walls so water does not pool against the base. The study makes clear that saturated concrete is the precondition for damage — if paver joints or weep holes are blocked, more water enters the pores that each cycle widens.
• Seal porous surfaces such as installed paver patios and exposed brick before temperatures hold below freezing. A quality penetrating sealer slows water uptake and gives your masonry more cycles before reaching critical damage.
• Call a licensed mason for an end-of-season inspection of any retaining wall, chimney or load-bearing feature that shows visible cracks, shifting pavers or crumbling mortar. Addressing freeze-related damage while the ground is still workable in October or November is far less expensive than waiting until the spring thaw reveals the full extent.

The CT scan research makes clear: what you see on the surface of a Long Island patio or wall in winter was already forming inside long before the first flake fell. Catching that hidden progress early — before the cracks become structural — is the difference between a simple repair and a full replacement.

When Your Hardscape Needs Professional Eye

Freeze–thaw damage does not show its full extent until months have passed, which is why a pre-winter inspection matters. If your patio has heaving pavers, your walkway shows scaling and spalling or you see cracks running through a retaining wall before cold weather sets in, the team at Long Island Stone and Masonry can assess what is reversible now versus what will need replacement once the ice cycle deepens.

Sources

• CT Scans and Simulations Reveal How Freeze–Thaw Cycles Crack Concrete from the Inside, Bioengineer.org, October 28, 2026
• CT image-based experimental and numerical simulation methods for freeze–thaw concrete microstructure, Discover Concrete and Cement, Vol. 2(1), Article 84, October 2026