Concrete Knowledge 100 Questions (4)

19. What items should be inspected when fly ash enters the factory?

A: The fineness and water requirement ratio of fly ash should be tested. The key item is water requirement ratio. 

If the fineness slightly exceeds the standard and the water requirement reaches the level II requirement, 

the ash can be used, otherwise it cannot be used.

20. What is concrete Admixture?

A: Additives used to improve the performance of concrete are called concrete admixtures.

21. What is the difference between water reducing agent and pumping agent?

Answer: Water reducing agent is the admixture to reduce water consumption and improve the strength of concrete 

under the condition that the work of the same concrete mix; The main raw material of pumping agent is water reducing agent, 

and then mixed with a small amount of plastic collapse protection components, in order to facilitate the pumping construction of concrete.

22. What kinds of concrete admixtures are there?

A: There are water reducing agent, pumping agent, retarding agent, accelerating agent, early strength agent, antifreeze, 

antifreeze pumping agent, expansion agent, waterproofing agent, etc.

23. Which items should be inspected when the pumping agent enters the factory?

A: Must test: water reduction rate, setting time, 1h slump time variation, compressive strength ratio. 

Conventional test can be used for C30 production of theoretical ratio test. It is not possible to replace the concrete ratio 

test with the flow degree of the clean pulp (the difference between the results of the clean pulp and the ratio test is too large, 

which is not conducive to guiding the production).

24. What is the detection status of good pumping agent?

Answer: Good pumping agent in the ratio of test, water reduction rate is not less than 20%, the workability of concrete mix is good, 

mortar wrapped with stone easy to flow, slump loss within 50mm. On the contrary: part of the stone surface non-stick mortar, poor liquidity, 

when slump > 80mm, that the quality of the batch of pumping agent is poor.