Ever wondered what is Gritting Salt and if you can eat it?

Gritting | Health & Safety | Snow Clearing | 23 June

Firstly, the very short answer is that we 100% advise against it! Rock salt (grit) is the salt of choice for winter maintenance service providers to treat roads, pedestrian areas, car parks, building entrances, stock grit bins, etc. It is 100% not for your fish and chips!

Grit salt, commonly scattered on icy roads during winter, may seem like ordinary table salt, but its composition and purpose are far more specialised. Many wonder not only what makes up this essential winter tool but also if it’s safe for consumption. This article delves into the makeup of grit salt and its effectiveness in combating ice and snow and addresses the common question of its credibility.

Gritting Salt

What is Grit Salt?

Grit salt, often referred to simply as road salt, plays a crucial role in winter road maintenance. Unlike the table salt used in kitchens, grit salt is specifically formulated for deicing and comes with a coarser grain. The primary component of grit salt is sodium chloride, the same chemical compound as table salt, but it frequently includes other materials like calcium chloride and magnesium chloride to lower its freezing point and enhance its ice-melting efficiency.

Grit salt may also contain sand or gravel to improve traction on slippery surfaces. These additives not only help prevent vehicles from skidding but also aid in the faster breaking down of ice as temperatures rise. By understanding its composition, it’s clear that grit salt is tailored for safety and effectiveness in specific, challenging conditions.

What is Grit Salt Made Of?

Grit salt’s effectiveness stems from its specially engineered composition, which is designed to combat ice and snow under diverse environmental conditions. Primarily made of sodium chloride, which is commonly known as rock salt, grit salt often includes other chemical additives that enhance its de-icing capabilities. These additives, such as calcium chloride and magnesium chloride, are hygroscopic, meaning they attract moisture. This ability is crucial as it helps the salt remain effective even in very cold conditions by lowering the freezing point of water, thus preventing ice formation.

Additionally, grit salt is typically mixed with anti-caking agents that prevent the salt from clumping in storage, ensuring it spreads evenly when applied to roads. Some formulas also include small amounts of sand or crushed stone to improve traction on icy surfaces, making them safer for both vehicles and pedestrians. The exact composition can vary based on regional climate needs and environmental standards, reflecting the tailored approach to maintaining road safety during winter.

How Does Grit Salt Work?

Grit salt functions primarily by lowering the freezing point of water, a process known as freezing point depression. When spread on icy surfaces, the salt begins to dissolve into the water present in the ice. This dissolution process forms a salt-water solution that has a lower freezing point than pure water, effectively melting the ice even at temperatures below 0°C (32°F).

This mechanism is further enhanced by vehicles’ movement over the treated areas. As cars drive over the salted roads, the pressure and friction generated help distribute the salt more evenly and speed up the melting process. Additionally, as the salt continues to dissolve and spread, it prevents the reformation of ice, maintaining safer driving conditions for a longer period.

Furthermore, the effectiveness of grit salt can vary depending on the ambient temperature and the concentration of salt used. For example, while sodium chloride works effectively down to about -9°C (15°F), adding calcium chloride can lower the effective temperature to as much as -29°C (-20°F), making it a valuable addition in colder regions.

Applications of Grit Salt on Roads

The primary application of grit salt is to ensure road safety by preventing ice formation and melting existing snow and ice on roadways. Its widespread use during winter months is crucial for maintaining traffic flow and reducing accidents caused by slippery conditions. Cities and municipalities deploy grit salt before anticipated snowfalls and throughout storm cycles to keep roads passable.

Grit salt is typically spread using specialized trucks that can evenly distribute the salt over large areas. These trucks may be equipped with spinning disks that help scatter the salt across all lanes of traffic, ensuring comprehensive coverage. This proactive approach is essential not only for highways and major roads but also for bridges, overpasses, and local streets where ice poses a significant risk.

Additionally, grit salt is used in combination with other strategies, such as ploughing and scraping. It often serves as a preliminary measure that reduces the bonding of ice to the pavement, making mechanical removal by ploughs more effective. In colder regions where temperatures may drop below the effective range of sodium chloride, a blend of different salts and even liquid deicers are used to maintain road safety.

Safety and Environmental Considerations

While grit salt is indispensable for winter road safety, it does come with certain environmental and safety concerns that need to be addressed. One of the primary issues is the potential for salt to cause corrosion. Sodium chloride, the main component in most road salts, can accelerate the rusting process in vehicles and degrade road infrastructure, including bridges and guardrails. This necessitates frequent maintenance and can increase repair costs for both vehicles and public works.

From an environmental perspective, the runoff of salt-laden water into local waterways can have detrimental effects on aquatic ecosystems. High salt concentrations can lead to increased salinity in freshwater bodies, which can harm fish and other aquatic life. Additionally, the accumulation of salt in the soil can alter its composition and negatively affect plant growth, potentially harming local flora and diminishing biodiversity.

Safety for humans is also a concern, particularly regarding the question of whether grit salt is safe to eat. It is not recommended for consumption due to the chemical additives and impurities it often contains, such as anti-caking agents and small amounts of heavy metals. These components are safe for road use but not for human ingestion, highlighting the importance of keeping grit salt separate from culinary salt.

Given these considerations, it is crucial for municipalities to manage the use of grit salt responsibly, balancing the immediate safety benefits against long-term environmental impacts.

Alternatives to Grit Salt

In response to the environmental and infrastructural concerns associated with traditional grit salt, several alternatives have been developed and are being increasingly utilised to manage ice and snow on roads. One popular alternative is calcium magnesium acetate (CMA), which is less corrosive and more environmentally friendly than sodium chloride. CMA works similarly to grit salt by lowering the freezing point of water but does so with fewer negative impacts on roads and vehicles.

Another innovative solution is beet juice and other agricultural by-products mixed with salt. These mixtures can be more effective at lower temperatures and are biodegradable, reducing environmental harm. Beet juice, in particular, helps the salt stick to the road better, reducing the amount needed and thus minimising runoff.

Additionally, brine solutions, water saturated with salt, are used as a pre-treatment before snowfall. Spraying brine can prevent ice from bonding strongly to the pavement, making it easier to remove and reducing the amount of solid salt required.

While these alternatives may present higher upfront costs or require new infrastructure for storage and application, their long-term benefits in reducing environmental damage and infrastructure repair needs make them a compelling choice for sustainable winter road management.

So Where Do We Get Our Salt From?

AccuGrit has two offices and strategic salt stores. One is our central UK location in Leicestershire, which could not be better positioned to support our UK-wide Gritting and snow-clearing teams. The other is our second office and depot in East Anglia, from which our control room and operations are masterminded.

If you are interested in finding out more about our winter maintenance programme and how we can provide unrivalled gritting and snow-clearing services by using advanced technology, then get in touch with our team today. [email protected]