How to judge the quality of sand and gravel aggregate?
Sand and gravel aggregate is an important raw material in the production of construction concrete and mortar, so the quality of sand and gravel aggregate is related to the quality of construction and other industries. So how do we judge the quality of sand and gravel aggregates?
1. Look at the cleanliness
First of all, the surface of the aggregate should be clean and contain few harmful impurities, otherwise it will affect the durability of the concrete. The control of cleanliness is mainly achieved through sand washing, screening and other links in the process of sand and gravel aggregate production;
2. Look at the particle gradation
The so-called particle gradation mainly refers to the situation where sand particles with different particle sizes are matched with each other. If the sand aggregate has a good particle gradation and a low gap ratio, it is beneficial to adjust the performance of admixtures and improve the performance of concrete. This kind of sand and gravel aggregate can be better sold in the market;
3. Look at the mud content
Generally speaking, the size of the mud content in the aggregate will directly and indirectly affect the strength of concrete, which will reduce the quality of concrete, and then affect the production quality of construction and other industries. For example, if the content of mud blocks in the aggregate of sand and gravel is large, the water consumption of concrete will increase, then its plastic retention performance will become poor, and the shrinkage will increase, which will lead to the decrease of concrete strength;
4. Look at the strength and firmness
This is mainly related to the processing raw materials of sand and gravel aggregates. We know that in the processing of sand and gravel aggregates, the raw materials can be selected from natural ores, such as granite, dolomite, etc., or solid waste, construction waste, etc. However, if the processing raw materials contain more clay minerals, tailings or weathered components, the strength and firmness of the finished aggregates are relatively poor, but it still needs to be judged according to the specific use.