Post Date: 26,Apr,2022

Effects of machine-made sand quality and admixture adaptability on concrete quality

The mother rock and production technology of machine-made sand in different regions are very different. The water absorption rate of machine-made sand affects the slump loss of concrete to a certain extent, and the excessive content of mud powder in machine-made sand will not only affect the strength of concrete, especially the solid return. Elastic strength and durability, resulting in the phenomenon of powdering on the concrete surface, and also unfavorable for the cost control of the mixing plant. The fineness modulus of the currently produced manufactured sand is basically 3.5-3.8, or even 4.0, and the gradation is seriously broken and unreasonable. The proportion between 1.18 and 0.03mm is very small, which is a challenge for pumping concrete.

1. During the production of machine-made sand, the content of stone powder must be strictly controlled to be about 6%, and the content of mud should be within 3%. The content of stone powder is a good supplement for broken machine-made sand.

2. When preparing concrete, try to maintain a certain amount of stone powder to achieve a reasonable gradation, especially to control the amount above 2.36mm.

3. On the premise of ensuring the strength of the concrete, the sand rate should be well controlled, the proportion of large and small gravel should be reasonable, and the amount of small gravel can be appropriately increased.

4. The washing machine sand basically uses flocculant to precipitate and remove the mud, and a considerable part of the flocculant will remain in the finished sand. The high molecular weight flocculant has a particularly great influence on the water reducing agent, and the fluidity and slump loss of the concrete are also particularly large when the amount of admixture is doubled.

Influence of Admixture and Admixture Adaptability on Concrete Quality

Power plant fly ash is already scarce, and milled fly ash is born. Enterprises with good conscience will add a certain proportion of raw ash. Black-hearted enterprises are all stone powder. Large, the activity is basically 50% to 60%. The amount of limestone powder mixed in fly ash will not only affect the loss on ignition of fly ash but also affect its activity.

1. Strengthen the inspection of grinding fly ash, grasp the change of its loss on ignition, and pay close attention to the water demand ratio.

2. A certain amount of clinker can be appropriately added to the grinding fly ash to increase the activity.

3. It is strictly forbidden to use coal gangue or shale and other materials with extremely high water absorption to grind fly ash.

4. A certain amount of products with water-reducing ingredients can be appropriately added to the grinding fly ash, which has a certain effect on controlling the water demand ratio.