Some coastal countries and regions have begun to consider using sea sand instead of natural river sand, such as the Netherlands, France and Denmark. China, with its long coastline and vast shallow seas, is rich in sea sand resources. Therefore, some areas such as Guangdong Province have begun to accelerate the mining of sea sand, but some areas still resolutely resist sea sand, such as Shanghai. The same is the coastal area, why is the attitude towards sea sand completely different? Can sea sand be used for concrete aggregate? If so, how to use sea sand for construction?
The workability, compressive strength, splitting tensile strength, compressive modulus of elasticity and carbonization resistance of concrete prepared with dry-processed manufactured sand (M-sand) are better than those of ordinary manufactured sand. In the case of little difference in workability, dry-process manufactured sand can save the amount of water-reducing agent, and manufactured sand produced by different production processes has the same effect on the electric flux of concrete.
To give full play to the pozzolanic activity, morphological water reduction effect and micro-aggregate filling effect of active admixtures and inactive admixtures, and improve the quality and performance of concrete, admixtures must have a finer particle size and larger than cement Specific surface area.
According to a large amount of data and practice, the blockage of pump pipeline is the most common problem in super high-rise structure concrete pumping.
The complete sand production system can produce manufactured sand for high-performance concrete. It must have the following five indicators
High-strength concrete has a low water-binder ratio and a large amount of cementitious materials, which leads to an increase in hydration temperature, so plastic shrinkage and self-shrinkage. Although high-strength concrete has a higher tensile strength, it has a high elastic modulus, which will cause higher tensile stress under the same shrinkage and deformation, so the risk of cracking in the early stage and during use cannot be ignored.
Mud content refers to the content of fine particles with a particle size of less than 75μm in sand, its mineral composition and chemical composition are different from those of the parent rock, and with relatively strong adsorption.