Building & Civil Engineering Structures - New Construction

Finishing

With the current emphasis on concrete as an aesthetic finish in its own right, it is no longer acceptable to leave behind visible blow holes and surface defects when formwork has been removed. The exciting, complex designs we are now able to produce can create their own problems with compaction, producing honeycombing; whilst inadequate formwork support may result in grout loss and unsightly blemishes. Even the removal of formwork often damages edges, arises and fine detail work. All of these defects require reinstating prior to completion with materials that are visually and structurally compatible.

Flexcrete has a range of materials to suit all applications, whether it be a structural mortar for reinstating large areas of honeycombing right through to colour-matched, fine grade mortars to produce the finest fair faced finish.

Some defects in the surface finish cannot be avoided and formwork designers utilise various tie systems to support and hold the shuttering in place. On removal these require filling to achieve a homogeneous finish and, where basements and water retaining structures are concerned, a watertight seal is vital.

Rapid setting, non-shrink fibre reinforced mortars are available from Flexcrete which reliably seal voids left by either snap-tie or through-tie systems. These can be used in conjunction with colour matched fairing mortars to blend in well with the surrounding concrete.

Reinstatement of Cover

The depth of concrete covering reinforcement on structures is set by design standards and codes of practice to ensure that the required life under the expected exposure conditions can be achieved. This is 60 years for normal structures and 120 years for bridges and tunnels.

Even modern, well designed buildings and structures can soon start to suffer deterioration as a result of poor workmanship during the construction sequence. Inadequate securing of the formwork or fixing of the reinforcement can lead to low cover and if this is not identified and appropriate remedial action taken, premature failure can be guaranteed. Spalling of the concrete is a consequence of the corrosion cycle, leading to costly repairs and an ongoing maintenance programme.

Just 2mm of a Flexcrete cementitious coating is equivalent to a minimum of 70mm of additional good quality concrete cover. These advanced products are polymer modified and offer outstanding resistance not only to water and carbon dioxide but also to chlorides. They form a homogenous bond to the substrate and their excellent UV and weathering resistance ensures that they will never need replacing during the design life of the structure.

Flexcrete’s products have been successfully used on many major infrastructure projects world-wide where costly pre-cast and in-situ elements have been simply, speedily and economically brought within specification. A 2mm application, by brush or spray, is all it takes.