Concrete can corrode when an alkali reaction in concrete occurs, causing cracks as well as damage to the structure. Lithium compounds can prevent damaging reactions like this when lithium admixtures are used in concrete. Lithium ions minimize damage and expansion by modifying the chemical composition of reaction products.
Lithium Nitrate is the most effective in preventing the negative effects of alkali-aggregate reactions. It is a lithium salt that doesn’t raise the pH value of the solution in the concrete pores. This rids it of the risk of the pessimum effect.
Lithium-based compounds can suppress expansion due to the alkali-silica reaction (known as ASR) in concrete. Lithium nitrate solution is often marketed as a chemical admixture that inhibits ASR.
A study was performed to determine the extent that a lithium admixture influences the properties of fresh as well as hardened concrete if used at the necessary dosage needed to suppress expansion caused by ASR.
Benefits of Lithium-based Products
Because lithium silicates contain smaller particles, they can evenly disperse into tight steel trowelled concrete. Some of the benefits include:
- Consistently fill empty pores
- Provide great density and abrasion-resistance
- Increased long-term durability
- Effectively penetrates concrete
- Reduces cleaning and maintenance needs
- Slip-resistant
- Improves the condition of older concrete floors
- Upgrade reflection & ambient lighting
However, inappropriate doses of lithium ions such as lithium carbonate as well as lithium hydroxide could lead to increased expansion and are deleterious to concrete, as has been found in studies on mortars and lithium.
With the addition of lithium salts, the cement’s setting time, amount of hydration, long-term strength, and expansion caused by ASR is affected. Depending on the reactivity levels of aggregates, lithium ions’ effectiveness can vary.
In the mortars containing lithium nitrate admixtures, expansion was reduced by up to 93% in mortars with gravel aggregate and lithium nitrate. This demonstrates that lithium is an effective inhibitor of expansion in mortars made with these aggregates.
Using Lithium in Building Materials
Lithium is most effective in the following materials:
- Opaline silica
- Chert
- Volcanic glass
Comparatively, lithium is less effective in the following as the reactive phase:
- Microcrystalline quartz
- Strained quartz
According to studies, the amount of necessary lithium increases along with the amount of alkali in the Portland concrete. Lithium-based admixtures need to be used in sufficient quantities to be effective. Lab testing has demonstrated that concrete affected by ASR can be topically treated with lithium-based compounds to slow the rate of expansion.
At Bisley International, we supply Lithium Nitrate and Lithium Acetate to mitigate ASR and other related problems like surface sweating. Protect your concrete by employing lithium acetate and nitrate into your building materials. Contact us today to find out more.
