Recommendations for Pumping Self-Consolidating Concrete

Mixing Strength With Satisfaction TECHNICAL REPORT RECOMMENDATIONS FOR PUMPING SELF-CONSOLIDATING CONCRETE Using self-consolidating concrete in vertical and overhead FORMWORK applications has become an accepted and proven concrete repair method. Based on the orientation of the • Formwork should be designed to be stronger than normal concrete formwork, repair, pumping self-consolidating concrete can be the in order to account for the hydraulic pressure exerted by the self-consolidating required method of placement for this material. However, concrete and any additional pressure from pumping. pumping can also be the preferred method of application, over form-and-pour techniques, as it can save time • Formwork should be designed to allow for air to escape from high points in and money. the form and provide points to observe the progression of the pour. If necessary 13 mm (½ inch) plastic tubing can be placed at extremely high points, to ensure King provides self-consolidating concrete technology that the air is pushed out of the form. in a pre-packaged solution. Our company offers MS-S6 Self-Consolidating Concrete for shallow depth • Minimum hose and valve sizes should be 38 mm (1½ inches) for MS-S6 repairs of 25 mm (1 inch) to 75 mm (3 inches) and Self-Consolidating Concrete and 50 mm (2 inches) for MS-S10 Self-Consolidating MS-S10 Self-Consolidating Concrete for full depth repairs Concrete. of 50 mm (2 inches) or greater. When pumping MS-S6 • Different types of valves can be used to connect hoses to the formwork, although Self-Consolidating Concrete or MS-S10 Self-Consolidating the most common type is the guillotine valve which can be seen in Figure 1. Concrete in a closed-form vertical or overhead application, The guillotine valve can be struck and closed when the self-consolidating concrete the following recommendations should be considered reaches or progresses beyond the valve opening. in order to ensure success. • Valves should be spaced at a maximum distance of 600 mm (2 ft) in both the horizontal and vertical directions of the formwork. • Formwork should be sealed as tightly as possible at the joints, as the paste of self-consolidating concrete tends to leak from the form more readily than normal concrete. PUMPING SEQUENCE • Pumping should begin at the lowest point in the formwork and move toward the highest point in the formwork, to allow air to escape through the subsequent valves and air vents. • All of the valves should be open during the pumping procedure until the concrete has progressed to the subsequent valve, at which point the current valve should be closed and the hose should be moved to the subsequent valve for pumping to continue. • The entire section of self-consolidating concrete should be pumped in one pour, without stopping. This procedure will help the concrete already in the formwork from Figure 1: Guillotine valve connected to formwork. losing slump flow before the formwork is completely filled. KING PACKAGED MATERIALS COMPANY 1-800-461-0566 • [email protected] • www.kingshotcrete.com Mixing Strength With Satisfaction TECHNICAL REPORT RECOMMENDATIONS FOR PUMPING SELF-CONSOLIDATING CONCRETE PRIOR TO PUMPING SELF-CONSOLIDATING CONCRETE • Ensure that the concrete pump intended for • For the optimum balance between strength development and slump flow retention, use is capable of pumping self-consolidating concrete temperatures should be maintained between 10ºC and 21ºC (50ºF concrete with either 6 mm (1/4 inch) and 70ºF). aggregate (MS-S6 Self-Consolidating Concrete) or 10 mm (3/8 inch) aggregate (MS-S10 • Maintain the concrete slump flow (Figure 2) between 600 mm and 700 mm Self-Consolidating Concrete), over the required (24 inches and 28 inches) at the exit of the pump hose, in order to promote proper distance. This information should be available consolidation. If the slump flow is below 600 mm (24 inches), the self-consolidating from the concrete pump manufacturer, although concrete may not be fluid enough to navigate highly congested zones of rebar. testing the pump set-up prior to commencing the work is also beneficial in some circumstances. • Host a pre-pour meeting to outline the pumping procedure and responsibilities of all crew members involved in the pour. *Note: King’s technical staff is available for pre-pour meetings or on-site consultations, in order to help contractors achieve a successful concrete repair. • Ensure that constant communication between the pump operator and the individual responsible for valve and hose placement can be maintained. Figure 2: Slump flow of self-consolidating concrete. • Fill the formwork with water prior to pumping, in order to check for water tightness and DURING AND AFTER PLACEMENT to saturate the parent concrete and formwork. • Do not vibrate the self-consolidating concrete during placement as this action can • Ensure that the parent concrete and formwork cause segregation. If necessary, tap the outside of the formwork to ease placement is in a Saturated Surface-Dry (SSD) condition, and indicate the level that the concrete has reached in the formwork. and that all excess water is removed from the formwork, prior to pumping MS-S6 Self- • The pump operator should be notified to stop pumping as soon as any stress Consolidating Concrete or MS-S10 Self- on the formwork or anchorage becomes apparent, when the concrete reaches Consolidating Concrete. the highest point of the form, or when the maximum design pressure of the formwork is reached. It is possible to blowout the formwork and cause failure if the pressure in This report is intended for use as a guide only. the formwork becomes too high. Please consult the Technical Services Department of King Packaged Materials Company for further • Once pumping has stopped, the last valve should be closed and the concrete should information regarding the pumping of self- be allowed to set and begin to develop strength. The forms should not be removed consolidating concrete for a specific application. until the concrete has achieved 75% of the indicated 28 day compressive strength. V0213 KING PACKAGED MATERIALS COMPANY Burlington Office Boisbriand Office Brantford Office Sudbury Office 3385 Harvester Rd. 3825 rue Alfred-Laliberté 541 Oak Park Rd. 644 Simmons Rd. Burlington, ON Boisbriand, QC Brantford, ON Dowling, ON L7N 3N2 J7H 1P7 N3T 5L8 P0M 1R0 Phone: (905) 639-2993 Phone: (450) 430-4104 Phone: (519) 756-6177 Phone: (705) 855-1155 Fax: (905) 333-3730 Fax: (450) 430-6855 Fax: (519) 756-7490 Fax: (705) 855-1122.

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