Section 613 — Simulated Stone Masonry Surface

Description

613.01This work consists of constructing simulated stone masonry surfaces using concrete, staining, and grouting to simulate the texture and color of native stone masonry in a stone pattern.

Material

613.02Conform to the following Subsections: Neat hydraulic cement grout 701.04(a) (2) Penetrating stain for concrete 719.05 Preformed expansion joint fillers 712.01(b)

Construction Requirements

613.03Form Liner Fabrication. Take an impression of the stone shape, texture, and mortar joints from a designated location. Design form liners from the impressions according to the stone pattern shown in the plans. Submit detailed drawings of the form liner according to Subsection 104.06.

613.04Test Wall. Before production work on the simulated stone masonry, construct a 36-inch- high by 24-inch-wide by 10-foot- long test wall according to Section 552 and this Section. Cast the test wall on site using the same forming methods, procedures, form liner, texture configuration, expansion joint, concrete mixture, and stain application proposed for the production work. Demonstrate the quality and consistency of joint treatment, end treatment, top embossing methods, back treatment, and stain application on the test wall. If a test wall is rejected, construct a new test wall. Start production structural concrete work after the test wall is approved. Start production stain application after the stain application on the test wall is approved. Dispose of the test wall after use.

613.05Form Liner Installation. Provide a form liner that attaches easily to the forming system. Install the form liner so it does n ot compress more than ¼ inch during the concrete pour. Attach the form liners to the form. Attach adjacent form liners to each other with less than a ⅛ -inch seam. Do not repeat the form liner pattern between expansion joints or within 20 -foot intervals, wh ichever is greater. Form expansion joints at the intervals shown in the plans. Blend the butt joints into the pattern and the final concrete surface. Coordinate the forms with wall ties. Place form tie holes in the high point of rustication or in the morta r joint. Clean off build -up before reusing form liners. Visually inspect each liner for blemishes and tears. Repair the liner before installation.

613.06Top Surface. Emboss the plastic concrete in the exposed top surface by stamping, tooling, troweling , hand shaping, or a combination thereof, to simulate the stone masonry texture and mortared joints. Match the side pattern of the formed mortared joints. After the free surface water evaporates and the finish embossing is complete, cure the concrete for 7 days according to Subsection 552.13(b) . Do not use liquid membrane curing compounds.

613.07Form Liner Removal. Within 24 hours after placing concrete, remove or break free the form liners without causing concrete surface dete rioration or weakness in the substratum. Remove form tie material to a depth of at least 1 inch below the concrete face without spalling and damaging the concrete.

613.08Preparation of Concrete Surface. Finish exposed formed concrete surfaces according t o Subsection 552.14(b) . Finish so that vertical seams, horizontal seams, and butt joint marks are not visible. Minimize grinding and chipping to avoid exposing aggregate. Provide a completed surface free of blemishes, discolorat ions, surface voids, and conspicuous form marks. Make the finished texture and patterns continuous without visual disruption. 613.09 Stain Application. Age concrete, including patches, at least 30 days. Clean the surface of latency, dirt, dust, grease, and foreign material by approved methods. Remove efflorescence with a pressure water wash. Do not sand blast surfaces that receive stain. Correct surface irregularities created by the surface cleaning. Maintain the concrete temperature between 40 and 85 °F w hen applying stain and for 48 hours after applying stain. Stain exposed concrete surfaces. Use a stain application suitable to obtain the appearance of the native stone masonry. Use at least 3 colors of stains. Provide protection and avoid over -spray and color overlap at boundaries between two color tones or between surfaces receiving color at different times. Apply grout of a natural cement color to each form joint. Use sufficient grout so the over -spray of the stain is not visible. Give the form pattern grout joint the appearance of mortared joints in completed masonry. Recoat areas inconsistent with the approved test wall. Treat expansion joints with caulk, grout, or both to blend with the appearance of the adjacent stone or mortar joint.

613.10Acceptance. Material for simulated stone masonry surface treatment will be evaluated under Subsections 106.02 and 106.03. Installation of form liners will be evaluated under Subsections 106.02 and 106.04. Application of stain to exposed concrete surfaces will be evaluated under Subsection 106.02. Construction of the simulated stone masonry test wall will be evaluated under Subsection 106.02. Construction of simulated stone masonry surfaces will be evaluated under Subsections 106.02 and 106.04.

Measurement

613.11Measure the Section 613 pay items listed in the bid schedule according to Subsection 109.02 .

Payment

613.12The accepted quantities will be paid at the contract price per unit of measurement for the Section 613 pay items listed in the bid schedule. Payment will be full compensation for the work prescribed in this Section. See Subsection 109.05 .