(1) Great loss of concrete slump
Causes of formation: poor adaptability of admixtures to cement or other raw materials; low admixture content; high temperature of cement or environment, fast hydration speed; improper use of concrete mix ratio.
Solutions: notify the additive manufacturer to adjust the adaptability of additives and cement, replace the raw materials with unqualified quality, increase the additive content, increase the mineral admixture content, and adjust the concrete mix ratio.
(2) too long coagulation time
Causes of formation: excessive dosage of retarder or sudden cooling did not timely adjust the amount of retarder, production did not pay attention to adjust the amount of additive according to temperature and retarder conditions; cement quality changes; mineral admixture quality problems; uneven mixing or mixing time is too short, the additive is not uniformly dispersed.
Solutions: adjust the dosage of additives according to the weather conditions; notify the supplier of additives to reduce the dosage of retarders or change the types of coagulants; replace cement or mineral admixtures; and adjust the mix ratio of concrete production in time according to the change of temperature.
(3) false coagulation
Cause of formation: Cement with anhydrite or industrial gypsum as setting agent meets cement containing xylithium or calcium sugar; admixture contains sodium carbonate early strength agent; triethanolamine dosage exceeds 0.1%; cement temperature is too high; premature strength agent dosage is too large.
Solutions: replacement of cement or admixture; control of triethanolamine content.
(4) Separation and bleeding
Causes of formation: improper mix ratio of concrete, low sand rate or cement material dosage; excessive admixture dosage, slump; better adaptability of cement and admixture; excessive carboxylate, phosphate or sugar in retarder.
Solutions: adjust concrete mix ratio, increase sand rate or increase the amount of cementitious materials; change retarder varieties, adjust the amount of additives; compound water-retaining components such as thickener or air entraining agent in additives.
(5) poor workability.
Cause of formation: low sand ratio or insufficient amount of cementitious material; low amount of admixture or poor water reducing effect.
Solutions: adjust the mix ratio of concrete, increase the sand ratio or the amount of cementitious materials; increase the amount of admixture.
(6) grasp the bottom
Cause of formation: too low water-binder ratio, too much water reducer and too much cement.
Solutions: adjusting concrete mix ratio, increasing sand ratio or increasing mineral admixture dosage; adding air entraining agent; reducing admixture dosage, etc.
(7) Concrete pan-alkali
Cause of formation: inorganic salt early strength agent, antifreeze agent content is too large; early maintenance is not good, water evaporation is fast.
Solutions: Reduce the dosage of inorganic salt admixtures, strengthen maintenance, and avoid early water loss.