Two employees were raking concrete in front of the concrete screed in a work zone. A semi-trailer entered the work zone and struck the concrete screed. The concrete screed then struck both employees and knocked them to the ground. Employee 1 suffered a fractured left leg and a laceration to the back of the head and was hospitalized. Employee 2 suffered contusions to both knees and the chest and whiplash. Employee 2 was treated and released.