“In one particularly tough area, the pour was a 10" (250mm) thick slab with double layer highway mesh (6x6 #3 rebar)(150x150 #10) chaired up every 4 feet (1200mm) using 4 foot (1200mm) bolster chairs. The chairs were laid parallel to the direction of screeding. This section of the pour was basically like walking on a spring-board. The S-840 continually traveled vertically 2"-4" (50-100mm) while riding on the mesh, in or out of concrete.
The slump for the job averaged around 3"-4" (75-100mm) with most of it on the 3" (75mm) side. The crew encountered some cold joints due to the pump moving but the machine blended the fresh concrete well, screeding parallel to the joint. They also screeded the concrete in one area when the machine was tilted 3-5" (75-125mm) lower on one side. The soft landing feature of the S-840 worked extremely well, leaving a very fine transition line, just like the Somero SXP®-D Laser Screed®.
In another 2,300 sq. ft. (230m2) section of the pour, with an 8" (200mm) slab and a single layer of mesh (6x6 #3) (150x150 #10), actual screeding time was 15 minutes, with no laborers working around or with the machine. Even though the machine was pulling 2-4" (50-100mm) of concrete there was never a loss of pulling power. And, the S-840 was intuitive enough to hold grade climbing out of the pour onto an 8" (200mm) slab and it did not leave any high or low spots in the concrete."