How do the thermal expansion coefficients of marble and concrete compare in planters?

When selecting materials for outdoor planters, understanding thermal expansion coefficients is crucial for long-term durability. Marble, a natural stone, has a relatively low thermal expansion coefficient of approximately 5-10 x 10^-6/°C, making it stable under temperature fluctuations. Concrete, on the other hand, typically has a higher coefficient ranging from 10-14 x 10^-6/°C, meaning it expands and contracts more with temperature changes.

In planters, this difference affects structural integrity over time. Marble's lower expansion rate reduces cracking risks in extreme weather, while concrete may develop microfissures due to repeated expansion and contraction. However, concrete's flexibility can sometimes accommodate stress better than brittle marble.

For outdoor use, marble planters offer superior resistance to thermal deformation but require careful installation to prevent stress points. Concrete planters are more affordable but may need reinforcement or expansion joints to mitigate thermal effects. The choice depends on climate, budget, and design priorities.