1. Advantages and disadvantages of wet mixed mortar
Wet mixed mortar is a ready mixed mortar that measures and mixes raw materials such as cement, fine aggregate, mineral admixtures, admixtures, additives, pigments and water in a certain proportion in the mixing plant, and then transports them to the construction site through a transport vehicle with mixing device for use, which is required to be used up within the specified time. The quality is stable and the supply quantity is large at one time. After arriving at the site, the mortar is stored first, and then the construction workers manually lay the mortar on the base material. Wet mixed mortar is produced in concrete mixing plant, which has the characteristics of accurate measurement and fast production speed. Wet mixed mortar is a kind of mortar mixture, and its use time is limited, so it must be used up within a certain time after production.
These characteristics of wet mixed mortar also show its advantages and disadvantages in development. Its advantages are as follows:
（1） Industrialized production is conducive to quality control and assurance;
（2） Large one-time supply, especially suitable for bridge pavement leveling layer construction, layer waterproof construction and other projects;
（3） There is no need for on-site mixing, which saves the expenses of drying equipment and packaging equipment;
（4） The construction site has good environment and less pollution;
（5） There is a wide choice of raw materials. The aggregate can be dry or wet without drying, which reduces the cost;
（6） It can be mixed with a large amount of industrial waste residue such as fly ash, which can not only save resources, but also reduce the cost of mortar.
Of course, it also has many disadvantages in production and use:
（1） Since it is well mixed by professional manufacturers, it needs to be stored in closed containers on site, and the one-time transportation volume is large, which must be used up in a limited time, so it is impossible to flexibly control the consumption according to the construction progress;
（2） There is a large amount of one-time transportation, so it is inevitable to store it in closed containers on site. Over time, it will have high requirements on the workability, setting time and stability of working performance of mortar;
（3） The time of transportation is restricted by traffic conditions.
2. Advantages and disadvantages of dry mixed mortar
Dry mixed mortar is a kind of ready mixed mortar, which is made of various dry raw materials in a certain proportion, accurately configured and mixed by the factory, transported to the construction site in bags or bulk, and mixed with water or supporting components in the specified proportion at the place of use. Therefore, compared with the wet mixed mortar, it is not limited by the use time and quantity, so it is the leading direction of the development of ready mixed mortar.
Dry mixed mortar has many advantages:
（1） The production efficiency is high. Because it is transported in the silo, automatically stirred, pumped and mechanically applied mortar, its production efficiency reaches 500% – 600% of the traditional production efficiency;
（2） The mechanized mixing of construction efficiency can ensure the correct treatment and construction of mortar, so as to avoid the occurrence of too much or too little mixing water and wrong formula;
（3） Mortar has many varieties, excellent quality, stable performance and convenient application;
（4） Economic benefits dry mixed mortar has good sand grading and small particle size. On the premise of ensuring the quality, the thickness of mortar can be reduced and the construction dosage can be reduced;
（5） Social benefits dry concrete mortar has realized the management system of integration of production, circulation and supply, which represents the industrialized production direction of new building cementitious materials. In addition, it can be used immediately with water, the operation is mechanized, the recognized working conditions are improved, and the labor productivity is improved.
However, dry mixed mortar still has the following disadvantages:
（1） The investment of dry powder mortar production line is relatively large, and the investment of bulk tanks and transportation vehicles is also large;
（2） Because the raw materials are mixed by dry raw materials, there are high requirements for the moisture content of materials, so there are certain restrictions on the selection of raw materials;
（3） Site water mixing is required during construction, so there are high requirements for the professional technology of material mixing personnel;
（4） In the process of storage and pneumatic conveying, it is easy to produce material separation, resulting in uneven mortar.