| Duracem |
New Zealand is home to many harsh environments which can impact on the usable life of concrete. Duracem has been specifically designed by Holcim New Zealand, using blastfurnace slag, to counter the effects of these aggressive environments.Marine Reinforced – Concrete in harbour and coastal works, marine structures and building exteriors exposed to sea air are susceptible to chloride attack. Countering chlorides is particularly important to avoid corrosion of steel reinforcement and consequent expansion, cracking and spalling of the concrete. Duracem reduces the permeability of the concrete, inhibiting chloride ions from reaching the steel. Processing – Industries based on dairying, meat, hides, fruit, forestry and fishing often generate acidic solutions which either by spillage or design come into contact with and corrode concrete floors, tanks and pipes. These can all benefit from the increased acid resistance of Duracem. Geothermal – Duracem provides resistance against the corrosive effects of sulphatic and acidic conditions found in geothermal areas. Waste Water – Sewage and water treatment facilities, including pipe and channel work, benefit from Duracem’s ability to counter sulphatic and acid conditions. Aggregates – Duracem cement offers maximum protection against cracking and deterioration of concrete which contains aggregates known to be potentially reactive with alkalis. The blastfurnace slag has a very low soluble alkali content while the relative impermeability of the concrete inhibits ingress of water necessary for the reaction to occur. Large Pours – With large concrete pours, reduced heat evolution is required at the early stages. The slower hydration of the blastfurnace slag component in Duracem results in a much lower heat of hydration than general purpose cement. Product Description Duracem is a blastfurnace cement with a nominal iron blastfurnace slag content of 65%. It is manufactured by intergrinding high quality blastfurnace slag in granulated form with cement clinker and gypsum. The granulated slag, a by-product of iron blastfurnace operations, has latent hydraulic properties that can be chemically activated to produce cementitious products. Gypsum, which is present in cement as a set regulator, and lime (Ca[OH]2), derived from the normal hydration of cement, serve as activators. Duracem is a light coloured cement. It has lower specific gravity than Portland cement, consequently a given weight of Duracem has a larger absolute volume than the same weight of Portland cement. This should be taken into consideration when designing concrete mixes. Further Information For more detailed information on Duracem, including a typical analysis and typical physical properties, please download the Duracem brochure by clicking the link on the right hand side of this page. |
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