Anchoring Grouts

Technologies offered by unsaturated polyesters to the construction industry are directed at specific areas such as anchoring grouts, resin mortars and concretes, coatings and lighting sealants. The properties that make unsaturated polyesters more useful for construction are (Boeing, 1964 Demmler and Schlag, 1971 Manson, 1985) ... 

Anchoring grout controllable setting time rapid strength gain corrosion resistance Securing bolts, bars, tendons or dowels in drilled or formed holes in concrete masonry or natural rock... 

Polyester anchoring grouts are supplied in two components, consisting of measured quantities of resin base and catalysed filler. The two components are mixed before application. 

Polyester anchoring grouts are of two types pourable grouts and thixotropic grouts. Pourable products are designed for vertically downwards or declining anchor holes prior to insertion of the anchor unit. The... 

Specific areas of application for polyester anchoring grouts are (Fosroc International, undated a) ... 

Hybrid anchors (not to be confused with hybrid adhesives as discussed in 4.3.2) combine the working principles of adhesive anchors with expansion or undercut mechanisms. Torque-controlled adhesive anchors (Figure 4.7) transfer tension loads via friction. Because of their ability to re-expand upon the application of tension loads, they are particularly suited for use in concrete that may crack over the anchor life, and may be used in a variety of applications where the flexibility of an adhesive anchor system is required. They are also less sensitive to hole cleaning procedures than ordinary adhesive anchors. Grouted undercut anchors, like standard undercut anchors, transfer tension loads via bearing. The grout improves the form-fit between the anchor and the concrete thereby reducing initial anchor movement under load. 

The devices are conceived to be inserted at the joint between perpendicular walls, as part of longitudinal steel anchors grouted within the thickness of the walls. Devices are designed to work in tension, similarly to traditional crossties, which experience axial loading when one wall panel tilts outwards as a consequence of ground acceleration. This type of installation ensures a low impact on the aesthetics of the building as it does not affect the finishes. 

When solid blocks or termite caps are used, anchor bolts must be placed in the joints between the blocks. Lintel blocks and grouted top courses allow for more flexible placement. 

In addition to the requirements of 3.3.7, anchor studs, such as J hooks, shall be welded to the underside of baseplate decks on maximum 300 mm (12 in.) centers to provide additional locking into the grout. 

L.4.6 All water and foreign materials shall be removed from the anchor bolt sleeves before grouting. 

L.4.7 After the baseplate is installed, the anchor bolt sleeve holes shonld be filled with a nonbonding material or the chosen gront, depending on the user s preference. This shonld be done before the main grouting of the baseplate. 

To install, the anchor is driven into the ground with a siedge hammer or a pneumatic tool. The explosive charge is pushed to the bottom of the anchor with a push rod and then exploded. A rapidly curing cement (grouting material) is then poured into the anchor ar H tamped to fill the camouflet enclosing the anchor tines (See Fig El)... 

Structural adhesives General-purpose adhesives Crack injecting systems Anchoring systems Grouts... 

Soil nailing is similar to ground anchors or tiebacks in that a steel rod is grouted into a pre-drilled hole. There are, however, several important differences. Nails are considerably smaller and shorter than anchors, and while anchors are pre-stressed after placement, nails are not (with few exceptions in which a very small pre-stress is applied), and do not pick up load until the soil mass deforms. Nails, like anchors, add shear resistance to the soil mass. 

Polyesters and expoxies have been used to seal cracks in rock formations and to anchor rock reinforcement members in drilled holes. The mechanical properties of these materials are much better than those of Portland cement. However, the chemicals are (relative to other grouts) very expensive and very viscous. Rendering them less viscous by using diluents so that they will penetrate sands makes them even more expensive. Because of their limited application as grouts, polyesters and epoxies are not detailed further. 

T. S-6. Massive mat construction for heavy vibration-producing equipment showing. . ee types of anchors (a) removable anchor (b) fixed anchor (c) grouting. 

Bone cement functions as a grouting material consequently, its anchoring power depends on its ability to penetrate between bone trabeculae during the insertion of the prosthesis [Charnley, 1979]. Being a viscoelastic polymer, it has the ability to function as a shock absorber. It allows loads to be transmitted uniformly between the implant and bone, reducing locahzed high-contact stress. 

Other names are also used to imply micropiles, such as Pin-piles, Mini-piles, Pali Radice (Root piles), Fondedile piles, Miga-piles, Pieux Racines, Wurzelpfahle and Estaca Raiz, but all essentially refer to small diameter drilled and grouted piles. The fundamental characteristic lies in its ability to be constructed with equipment used for anchoring and grouting, unlike conventional piles that need to be driven or bored (Bruce Nicolson 1988). 

Qualify by testing. Cast-in anchors recommended. High strength anchor bolts preferred (pre-loaded). Redundant anchors desirable. Avoid grouted-in anchors. Through wall anchors are best. 

There are two basic methods by which steel bolts and bars may be anchored into concrete, masonry or brickwork utilising epoxy or polyester resin grouts(5). The first involves inserting a deformed bar or bolt into a preformed or drilled hole into which the resin grout has been poured (Fig. 7.3). 

Post-tensioning is the process of casting the concrete wdth ducts in. After the concrete has hardened and developed sufficient strength cables in the ducts are tensioned and anchored. Ducts may be filled with cement grout (bonded) or with protective grease (unbonded). The grouting process is vital to the corrosion protection of the posttensioning cables. 

Every bar in each curtain of two-way reinforcement of the new web which terminates at the interface with a frame member is fuUy anchored into that member. To this end, the bar is lap-spliced with a same-diameter starter bar, which is in turn epoxy-grouted into the frame member over the embedment length needed for the development of the bar s full yield force. Lap splices are dimensioned per (CEN 2004). 

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