One of them is anti-freezing concrete hardening accelerator which helps carry out concrete tamping in low temperature without corrosion of reinforcement bars.

It was developed by the Pyongyang Jonghyang Building Materials Factory, one of building materials producers in the DPRK.

The factory produces scores of kinds of building materials, including concrete additives, waterproof agents and inorganic heat-insulating materials, for green architecture and dry-process fabrication.

Its products have been applied to the construction of monumental edifices like the Sci-Tech Complex and Ryugyong General Ophthalmic Hospital.

The factory is located in Rangnang District.