Concretes and grouts need to be designed and developed for their particular application and to overcome marine conditions.

Mix Parameters Typical Mix Design and Control
Strength and Durability - Mix design and testing
Mix Separation - Pumping/ placement in tremi fashion
Avoid Mix Washout - Provide protective compartments where needed
Fluidity - Flow cone control, pumping/ filling trials where required
Fluid Period - Retard mix beyond filling period, control compartment size
Top Laitance Layer - Avoid horizontal joints between pours (back up systems)
Shrinkage - Use additive where required
Thermal Cracking - Mix engineered where required
Environmental - Check pH rise and any local issues

Mix design, development and testing is more complex and important for successful maritime work as it has to meet a wider range of parameters in more onerous conditions. We regularly undertake this work and provide advice on mix and pumping arrangements and filling plans.

Traditional concretes are often used for simple mass pours where side confinement is provided and conditions are sheltered to avoid wash out during placement. Fluidity is limited for horizontal travel, but it is cost effective when appropriate

Micro Concrete
Micro concrete is a sand: cement mix with an aggregate size usually below 5 mm. This form of mix has traditionally been used for concrete mattress scour protection work and other uses of fabric formwork where it protects from wash out. The free water bleed from the mix increases strength and durability. It is important to select good local sands to achieve a reliably pumpable mix with good fluidity.

Automated concrete pumpingTypical Micro Concrete Mix Sheet (B65)
Concrete Mattress System (B66)

Neat Cement Grouts
These mixes have often been used for the grouting of :-
• Wide and sheltered bases
• Enclosed joints
• Grout Bag foundation and joint systems

These grouts are highly prone to wash out, and in other than still protected conditions, are often used with grout bag protection. Mixes are highly fluid with compartment lengths up to 24 m achieved. Neat cement grouts are relatively easy and reliable to pump and are often chosen for important or irreversible construction. Typical strengths are 50 to 70 N/ mm².

Past Projects

Retaining Wall, Hunterston (B118)