Masonry Magazine October 2011 Page. 24
CASE STUDY
HARDSCAPING
By Brett Martin
Caring for Hardscapes in Cold Climates
The Effects Deicing Salt Can Have On Pavers
Every year in the northern United States, homeowners, business owners and public employees spread deicing salts on roads and walkways to melt snow and ice. While these salts can effectively eliminate slippery conditions, they also may adversely affect landscaping and hardscaping pavers by causing visual and structural damage. However, properly manufactured pavers can resist the degradation caused by the salts.
WITHSTANDING COLD CLIMATE CONDITIONS
Interlocking concrete pavers typically perform better in colder climates than rigid asphalt and solid concrete surfaces. "The high compression, low absorption rates of pavers make them more resistant to deicing agents," says Len Browning, technical advisor for Belgard Hardscapes by Oldcastle.
Resistance to salts is related directly to a low absorption rate and a high compressive strength, and pavers generally outperform solid concrete and asphalt in both areas.
"The quality of aggregate materials used to manufacture pavers is an important component in the performance of pavers and their resistance to deicing salts," says Browning. "Belgard sources aggregate materials that are high strength with low absorption rates, and no deleterious material that may contaminate the finished product."
This produces a high-quality, salt-resistant surface that withstands extreme weather better than other surfaces.
Additionally, pavers withstand expansive soils and freeze-thaw movement better than rigid asphalt and solid concrete, which often crack under this type of shifting. Water can enter these cracks, and subsequent freeze-thaw cycles that cause the trapped to water to freeze and expand can cause additional damage to paved surfaces. By contrast, pavers shift with the movement of the ground, avoiding cracking and consequential damage. Properly constructed pavers create a flexible, load-bearing surface that can accommodate ground movements without sustaining damage.
According to the Herndon, Va.-based Interlocking Concrete Pavement Institute (ICPI) Technical Committee, concrete pavers have these advantages over ready-mixed concrete:
* Stronger aggregate bonding from higher cement content than typically used in pavement quality concrete
* Smaller aggregates for more surface area for the cement to bond
* Lower water-to-cement ratio, and vibration and compaction during the manufacturing process to increase aggregate-cement contact and eliminate overwatering
* Produced in a highly controlled manufacturing plant, leading to lower variation in material properties and eliminating surface over-finishing
* Can be successfully installed in cold weather, since they are cured before leaving the manufacturing plant.
UNDERSTANDING THE INDUSTRY STANDARD
Lou Mangiaracina, VP of sales in the Northeast for Belgard, has witnessed the effects that excessive use of deicing salts can have on pavers. "I've seen salt damage pavers in as little as three years," says Mangiaracina. "After a while, salt buildup can disintegrate pavers, if they are not properly manufactured and maintained."
Contrary to some consumer misperceptions of industry advertising claims, no paver is truly deicing salt proof, although most are deicing salt resistant. Fortunately, ways to extend the lifespan and appearance of pavers, even where salts are used, do exist.