RepairQ We have a client that has requested a shotcrete application for a dirt crawlspace. The facility is located in the Northeast part of New York. I’m not the designer, but I believe we are looking at a wet-mix, applied at a 4 in. (100 mm) depth throughout the crawlspace. I had a few questions I was hoping could get answered as we move through the technical specifications process. 1) Is there an off-season for the shotcrete product? Does it have to be applied in warm weather? Again, this is upstate NY. 2) What kind of equipment is used to dispense/place the product? (same as concrete?) 3) What is the noise level of the dispensing equipment? Typical of any concrete pour or much louder? The facility is a childcare center, so they are concerned about noise levels.
Here are the answers in the same order as your list.
- Shotcrete is just a placement method for concrete, so there is no “off-season.” However, as with cast concrete, cold weather placement needs more planning and material delivery controls. As wet-mix shotcrete material is predominately delivered by ready-mix trucks, the concrete should be delivered at 50°F (10°C) or higher. Then once shot, if temperatures are less than 50°F, the concrete should be protected by insulated blankets or the area enclosed by vented heaters to keep temperatures above 50°F. We also don’t want to shoot onto frozen surfaces.
- We use small line concrete pumps standard in the concrete industry.
- Concrete pumps and air compressors are generally diesel-powered engines. Pump engines range in horsepower from 75 to over 200 hp, depending on the pump size. Your application is of relatively low volume, so one of the smaller pumps should do fine. We also use relatively small air compressors, and many contractors who work in residential or metropolitan areas use equipment equipped with sound reduction. The sound at the point of placement where the air-accelerated material stream exits the nozzle is generally just the sound of the airflow.
