Wet-Process Equipment Overview
The development of efficient, swing-tube concrete pumps in the 1970's allowed the practical application of wet mix shotcrete which advanced the use of high volume shotcrete placement. Today Allentown Shotcrete Technology, Inc. designs, engineers and manufactures a wide range of wet-process equipment including: Pumps, Combination Mixer-Pumps, Mixers, Chemical Dosing Pumps, Nozzle Carriers, Mortar Machines and Concreting Machines.
WET-PROCESS FREQUENTLY ASKED QUESTIONS
- When was the wet-process developed?
- How does the wet-process work?
- What are the advantages of the wet-process?
- What are the disadvantages of the wet-process?
When was the wet-process developed?
The wet-process was developed in the 1960s with pressure tanks being used to force a stiff mortar through a hose. Additional air was added at the nozzle and the process came to be known as Shotcrete. The subsequent development of dependable concrete pumps of various types hastened the advancement of this technology, and today the wet-process is widely used and favored for certain applications.
How does the wet-process work?
All ingredients, including water, are thoroughly mixed and introduced into the shotcrete equipment. Wet material is pumped to the nozzle where compressed air is introduced to provide high velocity for placement and consolidation of the material onto the receiving surface.
Most wet-process shotcreting is done with premixed mortar or small aggregate concrete. The mix design and consistency of supply are very important in order to provide a mix with the workability or plasticity to be pumped through a small-diameter hose.
Sand gradation is the same as for the dry process and for coarse aggregate mixes, 20-30 percent of 3/8" aggregate is added. Cement content will vary according to the aggregate gradation and surface area; however most mixes contain approximately 700 pounds or more of cement.
What are the advantages of the wet-process?
- Little or no formwork is required.
- Cost effective method for placing concrete.
- Ideal for irregular surface applications.
- Allows for easier material handling in areas with difficult access.
What are the disadvantages of the wet-process?
- Equipment is more costly.
- Wet concrete requires special handling.
- Cleanup must be a consideration.