Holmesdale Tunnel

RonaBond Concrete Cover 150, played a part in a major project to improve traffic flow and safety on the M25 near Waltham Cross; a busy stretch of road taking 120,000 vehicles daily.

 

The £75 million project involved adding extra lanes to the Holmesdale Tunnel and upgrading lighting, ventilation, incident detection systems and CCTV in the tunnel. An extra lane was also added to the M25 eastbound through junction 25.

 

Part of the widening scheme involved partial removal of concrete, exposing steel reinforcement.  RonaBond Cover Plus 150 was used to coat the concrete and exposed steel, thus returning reinforcement cover.

 

RonaBond Concrete Cover 150 is formulated to improve equivalent reinforcement cover to concrete where actual cover is low or absent.  RonaBond Concrete Cover 150 is supplied as a pre-packed product, comprising liquid and powder components. It is mixed to form a slurry which is applied in as many coats as may be needed to produce the required equivalent cover.  The appearance or concrete protection may be enhanced by application of coloured anti-carbonation coatings from the RonaBond range.

DRYING OF SCREEDS

BS 8204-1 “Concrete bases and cementitious levelling screeds to receive floorings — Code of practice” section 6.11.1 suggests the following calculation for drying of screeds with no fast drying additi ...

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AVOIDANCE/ MITIGATION OF THE EFFECTS OF COMMON FORMS OF CRACKING IN CEMENTITIOUS SCREEDS

Aggregate is usually 0–4 mm and is mixed with cement in the ratio of 1:3 or 1:4 cement to sand, depending on strength requirements and drying requirements. For total screed thicknesses in excess of 50 ...

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Carbonation of Reinforced Concrete

Carbonation is the single most common cause of reinforcement corrosion in above ground structures and although many construction professionals and contractors are familiar with the progression of carb ...

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