Sulfate-resisting Portland cement (SRPC) is a special purpose cement used where sulfates are present in concentrations that would damage Normal Portland cement concrete or mortar. Sulfate resistance is achieved by adjustments to chemical composition to limit the level of tricalcium aluminate (C3A) in the SRPC. SRPC is made by fusing together a precisely controlled blend of very finely ground limestone, shale and iron oxide at high temperatures to form cement clinker. A small quantity of gypsum is added to this clinker before grinding to produce the final fine powder - Sulfate-resisting Portland cement. SRPC is manufactured in a modern dry process works at Platin, Co. Meath and is supplied in bulk. The quality of all SRPC produced by the company is guaranteed to meet in full the requirements of British Standard 4027 : 1996 ‘Sulfate-resisting Portland cement’ and is independently certified to BS 4027 by the British Standards Institution. Sulfate-resisting cement is specified in concrete for certain sulfate exposure classes as described in Irish Standard I.S. EN 206-1:2002 (see Table F1 (IRL)). Typical applications include concrete structures in sewage treatment works and sub-structures on reclaimed ground. The use of SRPC is not recommended in BS 6349 Part 1 ‘Maritime structures’ for reinforced concrete in contact with seawater. Due to the lower level alkalis in SRPC, arising from its chemical composition, it is sometimes used to provide greater resistance to the risk Alkali-Silica Reaction in concrete. The suitability of admixtures for use with SRPC should be specifically mentioned on adminxture suppliers literature. Regular information is available on the performance aspects of SRPC which are of direct interest to specifiers and users. The requirements of British Standard 4027:1996 (BS 4027) are compared hereunder to typical performance data for Sulfate-resisting Portland Cement class 42.5N. BS 4027 requires a minimum initial setting time of 60 minutes. Initial setting time for SRPC typically exceeds 100 minutes. Minimum compressive strengths for standard mortar prisms of 10MPa at 2 days and 42.5MPa at 28 days are stipulated in BS 4027 for cement class 42.5N, in accordance with statistically based compliance rules. Class 42.5N typical mortar prism strengths are in the range 50-60 MPa at 28 days for SRPC, with approx. 70% of this strength achieved at 7 days. Users are particularly interested in strength development and durability in concrete. Concrete strength is significantly affected by mix constituents and proportions, ambient temperature and the efficiency of curing. A durable concrete requires an adequate cement content, a low water/cement ratio and to resist sulfate attack, the correct cement type. Guidance is available in Irish and British Standards for concrete and concrete products and for all applications, directly from Irish Cement’s Technical Marketing Department. Sulfate-resisting Portland cement clinker consists predominantly of compounds formed from calcium, silica, alumina and iron. Calcium sulfate is present in cement due to the gypsum addition to control setting time. Specific chemical data (e.g. alkalis and chlorides) is provided regularly on test certificates Detailed information on chemical and compound composition is available on request.

Normal | Rapid Hardening | Sulfate-resisting | Other

About Us | Products | Customer Support | Technical Support | The Environment Quality Policy | Health & Safety | Contacts | Site Map | Home

Irish Cement Ltd., Platin, Drogheda, Co. Louth, Ireland. Tel: ++ 353 41 987 6000 Fax: ++ 353 41 987 6400 email: info@irishcement.ie