In the process of construction management, the commonly used concrete admixtures are early-strength admixture, superplasticizer, retardants, antifreeze agents and so on. Following are the brief introduction of several kinds of admixtures used in winter.
1 Water Reducing Agents
Use water reducing agents can reduce the moisture content of the concrete, make the ice crystals fine and uniform, further reducing destructive power of ice water on the concrete. Thus, water reducing agent used in winter construction of concrete is essential. Currently, the more common varieties of water reducing agent are:
(1) lignin sulfonate (calcium or sodium) common reducing agent;
(2) naphthalene sulfonic acid formaldehyde condensation product superplasticizer;
(3) polycyclic aromatic sulphonate formaldehyde condensation product superplasticizer;
(4) formaldehyde condensation product superplasticizer melamine sulfonate;
(5) the aliphatic superplasticizer;
(6) polycarboxylate water reducing agent;
(7) modification of lignin sulfonic acid calcium (or sodium) of superplasticizer.
Naphthalene water reducing agent and aliphatic water reducer is the main kind Winter construction. Besides, early strength composite components of polycarboxylate water reducing agent in winter construction of concrete is more common.
2 Air-entraining Agents
Add air-entraining agent can introduce closed tiny pores (air content in 3%-5%) in concrete and these pores can buffer produced by mixing water ice volume expansion. This helps to resistance to early frost damage and improve the durability of hardened concrete. According to chemical composition of air-entraining agent can be divided into the following categories:
(1) wood resin acids;
(2) the detergent category;
(3) lignin sulfonate salts;
(4) oil acid salts;
(5) hydrocarbon organic sulfonic acid salt.
When it is needed to be air entrained concrete in winter construction, air-entraining water-reducing agent can also be used, such as sodium calcium lignosulphonate, wood and polycarboxylic series of water reducing agent.
In addition, rust inhibitor in reinforced concrete engineering to reduce or prevent corrosion of metal embedded in concrete to improve the durability of concrete in winter construction. If you have interest in construction chemicals of OKCHEM, please visit https://www.okchem.com to get more!