2008-417A - Laserfiche WebLink

Home Browse Search

templates . If using sheet metal templates , ensure that they are of the dimensions , and are set to the lines , shown in the plans . Hold templates firmly while placing the concrete . Leave templates in place until the concrete has set sufficiently to hold its shape , but remove them while the forms are still in place . Saw contraction joints , for machine placed items , unless the Engineer approves an alternate method . Saw the joints as soon as the concrete has hardened to the degree that excessive raveling will not occur and before uncontrolled shrinkage cracking begins . Space contraction joints at intervals of 10 feet [3 m ] except where closure requires a lesser interval , but do not allow any section to be less than 4 feet [ 1 . 2 m ] in length . 520 - 6 . 2 Expansion Joints : Construct expansion joints at all inlets , at all radius points , and at other locations indicated in the plans . Locate them at intervals of 500 feet [ 150 m ] between other expansion joints or ends of a run . Ensure that the joint is 1 /2 inch [ 13 mm ] in width . 520 - 7 Finishing . 520 - 7 . 1 Repair of Minor Defects : Remove the forms within 24 hours after placing the concrete , and then fill minor defects with mortar composed of one part portland cement and two parts fine aggregate . The Engineer will not allow plastering on the face of the curb . Remove and replace any rejected curb , curb and gutter , or valley gutter without additional compensation . 520 - 7 . 2 Final Finish : Finish all exposed surfaces while the concrete is still green . In general , the Engineer will only require a brush finish . For any surface areas , however , which are too rough or where other surface defects make additional finishing necessary , the Engineer may require the Contractor to rub the curb to a smooth surface with a soft brick or wood block , using water liberally . Also , if necessary to provide a suitable surface , the Engineer may require the Contractor to rub further , using thin grout or mortar . 520 - 8 Curing . 520 - 8 . 1 General : Continuously cure the concrete for a period of at least 72 hours . Commence curing after completely finishing and as soon as the concrete has hardened sufficiently to permit application of the curing material without marring the surface . Immediately replace any curing material removed or damaged during the 72 hour period . After removing the forms , cure the surfaces exposed by placing a berm of moist earth against them or by any of the methods described below , for the remainder of the 72 hour curing period . 520 - 8 . 2 Wet Burlap Method : Place burlap , as specified in 925 - 1 , over the entire exposed surface of the concrete , with sufficient extension beyond each side to ensure complete coverage . Overlap adjacent strips a minimum of 6 inches [ 150 mm ] . Hold the burlap securely in place such that it will be in continuous contact with the concrete at all times , and do not allow any earth between the burlap surfaces at laps or between the burlap and the concrete . Saturate the burlap with water before placing it , and keep it thoroughly wet throughout the curing period . 520 - 8 . 3 Membrane Curing Compound Method : Apply clear membrane curing compound or white pigmented curing compound , as specified in 925 - 2 , by a hand sprayer meeting the requirements of 350 - 3 . 10 , in a single coat continuous film at a uniform coverage of at least 200 square feet per gallon [0 . 2 L/ M2] , Immediately recoat any cracks , checks , or other defects appearing in the coating . Thoroughly agitate the curing compound in the drum prior to application , and during application as necessary FAEngineering\Special Projects\Enclave Subdivision\Contract Documents\Contract Documents\The Enclave . doc\961 lA & 0001 - Technical Provisions.doc . 12 -