The effect of superplasticisers on OPC and PPFA concrete

• Autorzy: Moffat I. , Klemm A. J.
• Języki publikacji: EN

Abstrakty

EN

Although the use of superplasticisers within cement is well established, there is still lack of consensus on their effect on the hydration process. The problem complicates even further, when superplastizisers are incorporated into the concrete mix containing Pfa as partial replacement. The aim of the paper therefore was twofold: firstly to assess the effect of partial replacement of OPC by PFa and secondly, to explore the effect of increased lever of superplasticizing admixture and reduced cement content on the PPFA. Comparative studies have demonstrated that improved long-term performance to that of OPC concrete is achievable with the addition of pulverized fuel ash (PPFA). Early strength of the PPFAC concrete is however compromised with parity being obtained after 80 days. Increased level of cement and PFA content does not always provide satisfactory results in terms of the 28 days compressive strength. Increased amount of fines and water content may lead to heaping up of the cement particles and altering workability. Introduction of a superplasticiser reduces water demand without the need to change the cement content. It is possible therefore to produce a concrete of 40 N/mm² strength and reduced level of water absorption.

Słowa kluczowe

PL

beton; mieszanka betonowa; superplastyfikatory; wytrzymałość betonu

• Wydawca: Wydawnictwo Politechniki Częstochowskiej
• Czasopismo: Budownictwo o Zoptymalizowanym Potencjale Energetycznym
• Rocznik: 2007
• Tom: nr (4)
• Strony: 219--225
• Opis fizyczny: Bibliogr. 11 poz., tab., wykr.

Twórcy

autor

Moffat I.

• Glasgow Caledonian University

autor

Klemm A. J.

• Glasgow Caledonian University

Bibliografia

• 1.Soroka I., Portland cement paste and concrete, The McMillan Press Ltd, UK 1979.
• 2.Smith L.A., The design of fly ash concretes, Institution of Civil Engineers, 1967, 770-789.
• 3.Day K.W., Concrete mix design, quality control and specification, (2nd edition), E and FN SPON, UK, 1995.
• 4.Hover K.C., Concrete mixture proportioning with water reducing admixtures to enhance durability: A quantities model, Journal of Concrete and Cement Composites 1998, 20, 113-119.
• 5.Erdogdu S., Compatibility of superplasticisers with cements different in composition, Journal of Cement and Concrete Research 2000, 30, 767-773.
• 6.Swamy R.N., Dhir R.K., Cement replacement materials (Volume 1), Surrey University Press 1986, 197-250.
• 7.Brandt A.M., Cement based composites. Materials, mechanical properties and performance, (1st edition), E and FN SPON, 1995.
• 8.Khatib J.M., Mangat P.S., Influence of superplasticizer and curing on porosity and pore structure of cement paste, Journal of Concrete and Cement Composites 1999, 21, 431-437.
• 9.Papayianni I., Tsohos G., Oikonomou N., Mavria P., Influence of superplasticiser type and mix design parameters on the performance of them in concrete, Journal of Concrete and Cement Composites 2004, 27, 217-222.
• 10.Babu K.G., Rao G.S.N., Efficiency of fly ash in concrete, Journal of Concrete and Cement Composites 1993, 15, 223-229.
• 11.Dhir R.K., Zhu W.Z., McCarthy M.J., Use of Portland PFA cement in combination with Superplasticizing admixtures, Journal of Cement and Concrete Research 1998, 28, 1209-1216.