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34 <br /> preceding vertical rebar stubs below. Insure rebar is installed according to the plans. Rebar <br /> should extend out of the concrete a minimum of 12"on partial wall filling. <br /> 8.3 Cement Specifications <br /> Use cement having minimum strength of 2500 psi or greater, as required by local code;the <br /> aggregate should be pea gravel no larger than 3/8"in diameter. Cement slump should be 6-7". <br /> Cement that is too stiff will not flow properly into the horizontal cavities and will cause <br /> incomplete beam formation.Cement mix that is too wet will reduce strength of the concrete and <br /> also create tremendous inertial pressures that could cause blowouts. <br /> 8.4 Concrete Pumps <br /> A line pump is recommended with a 2"to maximum of 2.5"outlet for good control of the <br /> process. Pumps with boom arms may be used but can be more difficult to control. Minimize the <br /> fall height through the boom arm to reduce the out flowing concrete pressure. Too high pressure <br /> can damage and shift wallforms. <br /> 8.5 Spiral Pour Method <br /> Concrete must be placed carefully so that equal pressures on the wall form are maintained. The <br /> optimum method for wall filling is to start at one corner and work around the entire perimeter of <br /> the building adding approximately 24"of concrete on each pass around the entire perimeter. This <br /> `spiral pour' method insures proper filling without voiding. Do not allow the mouth of the pump <br /> hose to contact and possibly damage the Wallforms. Also,any extra length of hose should be <br /> kept away from the Wallforms as the weight of the concrete pushing laterally against unfilled <br /> Wallforms could cause slight shifting. Do not fill the wallforms to the top surface if this is not <br /> the final lift. To assure optimal strength and bonding of the concrete between the various <br /> pours/lifts within the overall wall, stop filling halfway up the topmost horizontal row of <br /> Wallforms(4 inches from the top). <br /> 8.6 Vibration <br /> Following the instructions above insures proper filling. Properly mixed concrete at the required <br /> slump will flow very well throughout the cavities. Typically,a simple"rodding"motion done by <br /> shelterWorks General Application and Technical Information(GATI)version 2.5 <br />