Fabrication and Installation - Offshore Structures: Design, Construction and Maintenance - page 380

promote thixotropic behavior, to increase strength, and to reduce bleed. Admix-
tures may be used to provide water reduction, retardation, and expansion char-
acteristics. It is important that trial batches be made to ensure that the grout has
the proper flow characteristics as well as strength. Flow rate should be kept low
to avoid entrapment of voids. Grout should be overflowed to ensure that the
initial mixture of cement and seawater is cleared. Pressures should be carefully
controlled to prevent forcing the grout out from under the jacket sleeve; usually
this exit is restricted by a grout retainer, but many times the grout retainer will
have been damaged during pile driving. Therefore, a second grouting entry pipe
is often provided, to permit the first grout to set and form a plug; then the main
grouting is carried out through the upper entry port.
The final installation of the platform is presented in Figure 5.53 .
FIGURE 5.53 Final installation.