Calcium Formate

01 Overview

Calcium formate is a salt formed from calcium ions (Ca²⁺) and formate anions (HCOO⁻). In cementitious systems, it is commonly used as an additive to improve early strength development and accelerate curing, especially in cold weather.

Calcium formate is white crystal with excellent fluidity, which is often used as an setting-Accelerator in mortar. In dry-mixed mortar products, such as thermal insulation mortar, tile adhesive, cement-based plaster, repair mortar, etc., in order to improve the early strength, high-alumina cement and gypsum are usually used as coagulant, (at low temperature, it is also necessary to add antifreeze ), calcium formate has a dual role as a new type of setting-Accelerator , which can accelerate the hardening speed of cement, improve the early strength, and avoid the slow setting speed of mortar in winter construction or low temperature and humidity. so that the mortar can be put into use as early as possible, especially contributing to the early strength.

ITEM STANDARD
Appearance White Crystal
Purity ≥98%
Calcium content ≥30.1
Moisture ≤1%
Bulk density(g/L) 900-1000g/l
Particle size(100mesh) ≤5%
Heavy metal 20ppm max
pH 6.5~8.0
Addition Rates

Dosage rates will be dependent on mix design, process, types of materials and the desired effect but typically:

500gms – 2000gms per 100 kg cement

(0.50% – 2.00% by weight of cement)

It is advisable to carry out preliminary tests to establish the correct dosage for the application.

 Application area

Calcium Formate can be used in concrete, dry mortar and tile adhesives, acting on both setting and hardening time by accelerating the formation of tricalcium alluminate silicate. Depending on the dosage of Calcium Formate, it also can strongly modify the initial workability of the wet mortar.

02 Application Features

Calcium formate is a kind of setting-Accelerator that can accelerates concrete/mortar coagulation and hardening, which means it can-

1,Shorten the initial setting time.

2,Normallzies the cement/mortar retardation under low temperature conditions.,

3,Increase the rate of early strength growth.

4,Shorten the mold closing time in the module during the production of concrete prefabricated parts.

5,Shorten the time of concrete reaching load capacity.

03 Questions & Answers

  1. 1
    Calcium Formate Synthesis Process

    Calcium formate is categorised into synthetic calcium formate and by-product calcium formate. Synthetic calcium formate is produced via two methods:

    1. Formic acid + calcium carbonate;

    2. COO + calcium hydrogen carbonate;

    The by-product method is subdivided into the pentaerythritol by-product method and the trimethylolpropane by-product method. By-product calcium formate contains organic impurities such as alcohols, exhibiting either a pungent odour or being odourless. These organic impurities or other substances significantly impact the later strength of mortar, rendering mortar quality uncontrollable.

  2. 2
    Differences in Calcium Formate Particle Size

    Calcium formate is available in powder, fine granules, and coarse granules. Due to its hygroscopic nature, powdered calcium formate readily lumps under high-temperature, humid conditions when subjected to compression, forming highly compacted lumps that prove difficult to pulverise. Fine and coarse granules exhibit superior flowability and larger bulk volume, making them less prone to lumping and thus the preferable choice.

  3. 3
    Why does synthetic calcium formicate solution appear slightly yellow?

    Because synthetic calcium formicate is produced by neutralising calcium carbonate powder. Calcium carbonate powder is ground from natural calcite, containing metal ions such as iron, copper, and magnesium. Consequently, the solution undergoes oxidation reactions, resulting in a yellow solution. The by-product formic acid reacts with calcium hydroxide, which contains fewer metal ions, yielding a clearer, more transparent solution.

  4. 4
    The effect period of calcium formate on mortar?

    At 5 ℃ low temperature, the influence law of calcium formate on the mortar strengths at 1 d, 3 d, 7 d and 28 d was studied in this work, and its effect on the early hydration of cement was also analyzed from the perspectives of hydration heat, hydration kinetics and hydration pro-ducts. The results showed that, calcium formate had a low-temperature early-strength effect, which could promote the early strength development of mortar at a low temperature of 5 ℃. And its effect time of strength improvement was mainly before 3 d, and its suitable dosage range was from 1% to 2%. The incorporation of calcium formate could promote the hydration reaction of cement at the initial stage (before 7 d), shorten the hydration induction period of cement slightly, advance the acceleration period, and advance the occurrence time of heat-releasing peak. Furthermore, the hydration heat release rate and cumulative heat release would be all increased significantly. Calcium formate increased all the hydration reaction rates of nucleation and crystal growth (NG)stage, phase boundary reaction (I)stage and diffusion reaction (D)stage, and extended the duration and increased the hydration degree of I stage. The incorporation of calcium formate increased the content of Ca(OH)2 at the initial stage of cement hydration, but the types of hydration products did not change significantly. –Materials Reports

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