Abstract: A concrete strike-off vibrator is characterized by a manifold member having at least one cylinder assembly disposed in a force-transmitting relationship therewithin. The manifold includes a pressurized fluid inlet adapted to introduce a pressurized fluid into the interior volume of the manifold. The cylinder assembly includes a piston adapted to define first and second volumes within the cylinder assembly and has associated therewith an intake for introducing pressurized fluid from the interior volume of the manifold into the first and second volumes defined within the cylinder assembly. Included is an exhaust isolated from the intake and from the interior volume of the manifold for venting the first and the second volumes within the interior of the cylinder assembly.

Abstract: A concrete control joint is characterized by a substantially T-shaped member having a slit extending substantially vertically through the upright member of the T to define first and second leg portions thereof. The lower ends of each leg portion are resiliently and hingedly connected together. An arm of the T is connected to the end of each leg portion opposite the hinged connection. The arms terminating in fingers which extend substantially perpendicular from the underside of the arms in a direction substantially parallel to the leg portions toward the hinged joint therebetween.