WELD-CRETE®
The original chemical concrete bonding agent incorporates polyvinyl acetate homopolymer in the patented formulation. For exterior and interior use, Weld-Crete® will bond new concrete, portland cement plaster, and cementitious mixes to structurally sound concrete floors, walls, columns, beams, steps and ramps. It can be "painted on" in a single application, 1 to 10 days prior to concrete placement. Use Weld-Crete's open time to your advantage in bonding to concrete shear walls, where you need a time lapse between application and bonding agent, placement of reinforcing steel, placement of formwork and placement of concrete. Weld-Crete® is also used for bonding setting beds for ceramic tile and for bonding portland cement plaster and stucco mixes; and to bond to such surfaces as brick, block, tile, marble, metal, glass block, soundly adhered paint (non-soluble in water), and silicone. Bonds new concrete, stucco, tile setting beds, and terrazzo to any structurally sound surface, interior and exterior. GUIDE SPECIFICATIONSDivisions 3 & 9 1. General 1.1 PRODUCT HANDLING a. Deliver Weld-Crete® to job in original container with seals unbroken and use without reducing. 1.2 ENVIRONMENTAL CONDITIONS 2.1 MATERIALS a. Bonding Agent: Weld-Crete®, Larsen Products Corp., Jessup, Maryland (Show bonding agent in cross section detail). 3. Execution3.1 SURFACE PREPARATION a. Surfaces to receive Weld-Crete® MUST BE CLEAN, free from loose material, dust, dirt, oil, grease, wax, loose paint, mildew, rust, laitance, or efflorescence. If preparing an old concrete floor surface (steel trowel finish), mechanically scarify the surface and follow with an acid wash and thoroughly rinse with clean water. An economical method for cleaning concrete floor surfaces is to use a 10% muriatic acid solution followed by a thorough washing. Degreasing solvents such as Varsol are also effective. Surfaces to receive Weld-Crete® MUST BE STRUCTURALLY SOUND. On newly placed concrete floors to receive a bonded topping, give the surface a rake or broom finish. Surfaces with form releasing agents, curing compounds, hardeners and sealers must be compatible with Weld-Crete®. Glossy painted surfaces should be dulled with an abrasive. New paint should cure 60 days before applying Weld-Crete®. Paint must be firmly adhered to undersurface. Do not apply over paints or materials that are soluble in water. Do not apply over frozen concrete or plastic surfaces. Weld-Crete® may be applied over dry or damp surfaces (eliminate all water puddles). Do not apply where hydrostatic pressure is present in the substrate. Surfaces should be inspected for excessive cracking and properly repaired prior to application of the bonding agent. 3.2 INSTALLATIONa. Application of bonding agent: Apply Weld-Crete® uniformly, using brush, roller or spray, to form a continuous blue film over entire surface. Allow to dry one hour. EXCEPTION: FAST SET PATCHING CEMENTS AND GROUTS MUST BE APPLIED WHILE WELD-CRETE® FILM IS STILL TACKY. 3.2.1 APPLICATION OF CONCRETE OVERLAYS: Delayed toppings shall be over Weld-Crete® in a minimum of 1/2 inch thickness on surfaces as shown and specified. Provide for a butt joint at adjacent edges. All joints must duplicate the joints in the substrate and all joints must be sealed against water penetration. Form isolation joints or cut with a dry vacuum saw. Cut control joints not more than one-half the depth of the concrete overlay. Remove standing water from newly bonded concrete surfaces. Concrete toppings can be applied as soon as film is dry or delayed a week to 10 days with no effect on bond. Follow same application for concrete overlays on precast hollowcore floor systems. See Figure 1. Follow Portland Cement Association standards. Follow accepted industry standards for protection of newly bonded concrete. Do not use a "wet" type saw to cut isolation joints on newly-bonded concrete overlays. Seal all joints against water penetration. 3.2.2 BONDED CONCRETE SHEAR WALL: Prior to application of Weld-Crete®, set all anchors on existing wall as shown and specified. Apply Weld-Crete® as directed, then proceed with placement of reinforcing steel, erection of forms and placement of concrete. Seal all joints against water penetration. 3.2.3 APPLICATION OF PORTLAND CEMENT TERRAZZO: shall be over Weld-Crete® to surfaces as shown and specified. 1/2 inch Portland Cement Terrazzo Flooring: install terrazzo dividing strips prior to application of Weld-Crete®. Follow NTMA specification for monolithic terrazzo. Do not allow standing water or wet materials to remain on newly bonded terrazzo surfaces. Seal all joints against water penetration. 3.2.4 APPLICATION OF PORTLAND CEMENT PLASTER: shall be over Weld-Crete® to surfaces shown and specified. (NOTE: Portland cement plaster can be applied as soon as film is dry or delayed a week to 10 days with no effect on bond). Seal all joints against water penetration. a. Two and Three Coat Applied: Apply scratch coat a minimum of 3/8" over Weld-Crete® on surfaces as shown and specified. (NOTE: Do not scratch through to Weld-Crete® film.) Allow to dry 24 hours. Follow with second and third coat applications. Seal all joints against water penetration. 3.2.5 APPLICATION OF MORTAR SETTING BEDS to receive ceramic tile, precast terrazzo, etc. shall be a minimum of 3/8" thickness over Weld-Crete® surfaces as shown and specified. Seal all joints against water penetration. 3.2.6 APPLICATION OF NON-SHRINK FAST-SET MORTARS AND GROUTS shall be over Weld-Crete® while Weld-Crete® film is still tacky. Seal all joints against water penetration. 3.2.7 APPLICATION OF BEDCOAT for Simulated Stone Finish (Marblecrete) shall be a minimum of 3/8" thickness over Weld-Crete® on surfaces as shown and specified. Seal all joints against water penetration. TECHNICAL DATATechnical services and laboratory facilities are available through the manufacturer. Distributors in principal cities throughout the United States and Canada can assist owners, developers, architects, specifiers, engineers and contractors. Write for nearest representative. See Table 1: Performance Properties. STANDARDS & APPROVALSASTM C 932; ASTM C 631; Military Specification, MIL-B-19235C (YD); General Services Administration Specification for Bond Adhesive; Corps of Engineers Specification CE-240.01; Canadian Standard CSA A 261; Approved: New York City Board of Standards & Appeals under Cal. No. 626-52 SM; City of Los Angeles Board of Building and Safety Commissioners (Research Report No. 2463). ac...availability/cost Weld-Crete® is available from building supply dealers throughout the United States and Canada. Obtain local quotations to determine cost factors. Coverage: 200 to 300 sq. ft./gallon, approximately, depending upon method of application, temperatures, porosity and texture of the substrate. Packaging: 55 gal. drum, 5 gal. pail, gal., and qt. Canada: available in litres. Color: Blue (non-bleeding) ACRYLIC ADMIX 101™Acrylic Admix 101™ is an integrally added bonding agent to bond new concrete, portland cement plaster, and mortar mixes, interior or exterior. It is an organic polymer (a white, milky liquid) which is mixed with varying proportions of water according to the performance required for the modified portland cement mix, i.e., tensile bond strength, etc. This ratio usually ranges from one part acrylic to one to three parts water. It also creates a hard, durable surface resistant to most chemicals and acids, imparts excellent water and weather resistance, improves curing qualities and reduces shrinkage cracking. Bonded assemblies are unaffected by water. GUIDE SPECIFICATIONS Divisions 3 & 91. General 1.1 PRODUCT HANDLING a. Deliver Acrylic Admix 101™ to job in original containers with seals unbroken. 2.1 MATERIALS a. Integral Bonding Agent: Acrylic Admix 101™, Larsen Products Corp., Jessup, Maryland. 3. Execution3.1 PREPARATION a. Surfaces to receive Acrylic Admix 101™ modified mixes MUST BE STRUCTURALLY SOUND and CLEAN, free from loose material, dust, dirt, oil, grease, wax, loose paint, mildew, rust, laitance or efflorescence. Surfaces with form releasing agents, curing compounds, hardeners and sealers must be compatible with Acrylic Admix 101™ mixes. For areas embedded with grease or oil, sandblast to clean surface or remove with a concrete cleaner and conditioner. Smooth, steel troweled surfaces should be scarified. 3.2 INSTALLATION 3.2.1 THIN CEMENT TOPPINGS: For portland cement/sand toppings (1 inch or less), use one part Acrylic Admix 101™ to two parts water. Mix to the proper workable consistency for troweling. Do not use a high speed mechanical mixer because this will entrain excessive air. Place the topping mix using a steel trowel, and spread to desired thickness. 3.2.2 APPLICATION OF MODIFIED PORTLAND CEMENT PLASTER one coat work to concrete. Use one part Acrylic Admix 101™ to two parts water and stir well in clean container before adding to dry portland cement mix (no lime is needed in the mix). Dampen surface to reduce suction, then apply the modified portland cement plaster to a total thickness not to exceed 3/8" thickness for finish. 3.2.3 APPLICATION OVER MASONRY SURFACES: Follow mixing instructions. To prevent masonry joints from shadowing through the finish, apply a thin dash or scratch coat of modified portland cement plaster, allow it to take up and double back to the full 3/8" thickness for finish. ac...availability/cost Acrylic Admix 101™ is available from building supply dealers throughout the United States. Packaging: 55 gal. drum, 5 gal. pail and gallon. Color: Milky White (dries clear). LIMITATIONS: DO NOT USE WITH HIGH EARLY STRENGTH CEMENTS, AIR ENTRAINING CEMENTS, OR WITH AIR ENTRAINING ADMIXTURES, or with cements, containing self-bonding adhesives. DO NOT PLACE FINISHES OR PATCHES AT TEMPERATURES BELOW 50°F, or when temperatures are expected to fall below 40°F within 24 hours. When high temperatures prevail with rapid movement, cover surface with wet burlap. Acrylic Admix 101™ fortified mixes are not suitable for use over surfaces dried with wax base curing and parting compounds. WARRANTY: Plaster-Weld®, Weld Crete®, and Acrylic Admix 101™ are suited for the purposes described when used according to directions. Buyer agrees in purchasing this product that Seller's liability for breach of warranty shall in no case exceed the price of the product. Because of the broad range of conditions beyond our control which may be encountered in the use of the product, Larsen Products Corp. makes no other warranty, express or implied, and no agent or other person is authorized to do so. Nevertheless, we will be glad to provide information about any type of installation you may request. LARSEN PRODUCTS CORP. |