1. The inspection items for early-strength agent and early-strength water-reducing agent entering the construction site (or concrete mixing station) should include density (or fineness), 1d, 3d compressive strength and corrosion effect on steel bars. For early-strength water-reducing agents, the water-reducing rate should be measured. If the concrete has finishing requirements, it should also be observed whether salt precipitation occurs on the surface of the concrete after hardening. Only when the requirements are met can it be stored and used.
2.: The early strong agent and early strong water reduction agent of the powder should be extended in the concrete dry material. When using natural curing for concrete, it is advisable to cover it with plastic film or spray curing solution. After final setting, it should be watered and moistened immediately. When the temperature is below 0°C, in addition to plastic film, insulation materials should also be added. Antifreeze should be used when the temperature is below -5°C.
4. When steam curing is used for concrete mixed with early strength agent or early strength water reducing agent, the steam curing system should be determined through experiments.
JH-II early strength agent and JH-7 early strength water-reducing agent are suitable for steam-cured concrete and concrete projects with early strength requirements constructed in environments with normal temperature, low temperature and temperatures below -5℃. . It is not advisable to use early-strengthening agents and early-strengthening water-reducing agents under hot environmental conditions.
2. Chemical substances that cause harm to the body or cause pollution to the environment after being mixed into concrete are strictly prohibited from being used as early strength agents. Early strengthening agents containing harmful components such as hexavalent chromium salts are strictly prohibited from being used in drinking water projects and food contact projects. Ammonium nitrate is strictly prohibited from being used in office, residential and other construction projects.
3. It is strictly prohibited to use early-strengthening agents and early-strengthening water-reducing agents containing chlorine salts in the following structures:
(1) Prestressed concrete structures;
(2) Structures used in environments with a relative humidity greater than 80%, structures in locations where water levels change, open-air structures, and structures that are often exposed to water or washed by water flow;
(3) Massive concrete;
(4) Structures that are in direct contact with acid, alkali or other corrosive media;
(5) Structures that are often exposed to temperatures above 60°C and require steam-cured reinforced concrete precast components;
(6) Concrete with decorative requirements, especially concrete that requires consistent color or metal decoration on the surface; (7) Thin-walled concrete structures, intermediate and heavy work Structures such as crane beams, roof trusses, drop hammers and forged hammer concrete foundations;
(8) Structures using cold-drawn steel bars or cold-drawn low-carbon steel wires;
(9) Concrete structures in which aggregates are alkali-active. </p
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