Epoxy grouts

All platforms, regardless of the type of grout to be used, should be designed with oil drains. Epoxy grouts are recommended on platform installations because they provide an excellent oil barrier for the concrete below. Cement grouts should be used only for temporary installations. 

Unless otherwise specified, the vendor shall commercially sand blast, in accordance with SSPC SP 6, all grout contact surfaces of the baseplate, and coat those surfaces with inorganic zinc silicate in preparation for epoxy grouting. 

L.2.2 Linear shrinkage of epoxy grout shall be less than 0.080 percent and thermal expansion less than 54 x 10 mm/mm/°C (30 X lO in./in./°F) when tested by ASTM C 531 test method. 

L.2.3 The compressive strength of epoxy grout shall be a minimum of 83 MPa (12,000 psi) in 7 days when tested by ASTM C 579 method 8, modified. 

L.2.4 Bond strength of epoxy grout to concrete grout shall be greater than 14 MPa (2,000 psi) when using ASTM C 882 test method. 

L.2.5 Epoxy grout shall pass the thermal compatibility test when overlayed on cement grout using test method ASTM C 884. 

L.2.7 Gel time and peak exothermic temperature of epoxy grouts shall be determined by ASTM D 2471. Peak exothermic temperature shall not exceed 45°C (110°F) when a specimen 15 cm (6 in.) diameter x 30 cm (12 in.) high is used. Gel time shall be at least 150 minutes. 

L.3.3 No push rods, chains, or vibrators shall be used to place epoxy grout under baseplates. 

L.4.2 Before an epoxy grout is applied, the baseplate temperature should be estimated to ensure that the grout can resist the expected temperature. 

L.4.4 All grease, oil, paint, laitance and other undesired materials shall be removed from the surfaces to be grouted. The roughened concrete snrface shall be blown with oil-free compressed air to remove all dnst and loose particles. When cementitions grout is used, the concrete smface shall be thor-onghly soaked with water imtil absorption stops, and any excess water shall be removed. When epoxy grout is used, all surfaces shall be kept dry before application. 

L.4.8 If voids are present after the grouting sequence, epoxy grout may be used to fill them. If cementitious grout is used, a full 28-day cure is recommended before this epoxy is applied. Epoxy grout is usually hand pumped through high-pressure threaded fittings installed in the baseplate where voids have been found. Extreme care should be taken to ensure that excessive pressures do not buckle the baseplate. At least one vent hole should be drilled into each void to help prevent excessive pressures. 

CF. [Qistom Fibers] Cellulose fibers reinforcing filler and vise, control agent for epoxy grouts, gasket material, mastics as asbestos replacement... 

Thixotropic epoxies are convenient when the adhesive has to be applied from below or on vertical surfaces (Fig. 1, left). Epoxy grouts are employed to fill large volumes and should, therefore, be able to eliminate trapped air bubbles, should not stratify, should exhibit alow cure exotherm and be self-levelling (Fig. 1, right). 

Figure 1. Application of a thixotropic adhesive to be used in conjunction with GFRP rods to strengthen a bridge stringer (left) and an epoxy grout to repair a carrier beam in a roof structure (right) [8] (reprinted with permission from Rotafix Ltd.).

Possible approaches to deal with this problem include partial reconstruction of timber structural members by replacing the degraded timber with epoxy grout cast on-site into a permanent timber formwork, or, preferably, replacing decayed material with a new timber splice in both cases, the load is transferred to the remaining sound timber by FRP or steel rods or plates (Fig. 5). 

In the case of decayed timber (Fig. 7(a)), the whole joint area may be replaced by a new solid structural node made with cast-in epoxy grout, connected with rods to sound timber parts (Fig. 7(b)). A much better alternative, although requiring more time and means and more skilled operators, is the individual repair of the members meeting in the joint, thus maintaining the original joint behaviour (Fig. 7(c)). 

Option (a) is an orthodox solution, strictly following the letter of design codes (CEN 2004), but is labour-intensive because many bars are epoxy-grouted into the frame members ... 

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). 

Option (b) is an indirect connection the smaU-diameter starter bars are omitted the dowels play the role of starter bars by extending into the web by at least the lap length of the web bar they intend to anchor into the frame member. The dowel bar is dimensioned in this case per fib 2012) for simultaneous tension (as an anchor) and shear (as a dowel) it is epoxy-grouted into the frame member for 8-times its diameter, or for the length needed to anchor the full yield force of the web bar(s)... 

Despite having reached ultimate conditions, specimen no. 1 sustained with little further strength degradation another quasi-static test of six cycles of lateral forces with inverted triangular distribution over all four floors (Fig. 16.8). Old cracks re-opened despite been epoxy-grouted, but the major one at the base monopolized the deformations when the top drift reached 1.2 %, its width exceeded 7 mm at one edge and 4 mm at the opposite. Interface slippage reached 3 mm at the base, but was modest at all other interfaces. 

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