ABOUT THE INTERNATIONAL CONCRETE ABSTRACTS PORTAL

  • The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

International Concrete Abstracts Portal

Showing 1-5 of 58 Abstracts search results

Document: 

SP221-47

Date: 

May 1, 2004

Author(s):

H. Saricimen, M. Shameem, M. S. Barry, and M. Ibrahim

Publication:

Symposium Papers

Volume:

221

Abstract:

Plain cement and silica fume cement paste and mortar specimens prepared using Type I cement, 8% silica fume, and potable and treated waters were tested for setting time and compressive strength. Pore solutions extracted from the mortar specimens were analyzed for alkalinity and chloride content. The results showed that the treated water tested in this study qualifies to be used in making concrete on the basis that the chemical composition of treated water and variations in the setting time and compressive strength were within the tolerable limits.

DOI:

10.14359/13290


Document: 

SP221-15

Date: 

May 1, 2004

Author(s):

D. Boubitsas

Publication:

Symposium Papers

Volume:

221

Abstract:

The aim of this paper is to introduce a method for determining the coefficient of efficiency, the k-value, with respect to chloride migration in concrete. Some results for ground granulated blast furnace slag are presented and compared with traditional k-values for compressive strength. Finally, some recommendations on how to use the k-values and how to improve standards and regulations are given. Standards normally give a single k-value for each type of addition, regardless of what environment the concrete will be exposed to. The results in the investigation, how-ever, clearly indicate that this is too great a simplification. For chloride migration, for example, the k-value is three times higher for slag than is the corresponding k-value for compressive strength. For a reliable service life prediction of concrete structures produced with concrete containing additions, it is, therefore, necessary to find relevant k-values for different types of degradation mechanisms. The most important mechanisms are corrosion induced by carbonation, by chlorides from the sea or by other chlorides, freeze/thaw attack with or without chlorides and perhaps also chemical attack.

DOI:

10.14359/13258


Document: 

SP221-46

Date: 

May 1, 2004

Author(s):

H. B. Mahmud, E. Majuar, M. F. M. Zain, and N. B. A. A. Hamid

Publication:

Symposium Papers

Volume:

221

Abstract:

This paper reports an investigation on the mechanical properties and durability of high strength concrete containing rice husk ash (RHA). Mixtures containing 10% RHA by weight of cement and w/cm of 0.27 were cast. RHA was incorporated either as an admixture or as cement replacement material. A superplasticizing admixture was used to provide flowing characteristics. Results on the workability, mechanical properties and initial surface absorption (ISA) test are reported. The specimens were subjected to water and air-drying conditions and tests on the specimens were carried out up to 180 days. By applying a superplasticizer based on polycarboxylic ether, workability of RHA concrete in the range of 200—250 mm slump can be attained. This type of concrete can achieve high strength of 80 N/mm2 at 28 days, irrespective of method of inclusion of rice husk ash or curing conditions. Compared to condensed silica fume (CSF) concrete at similar w/cm and workability, the strength of RHA concrete is about 6% lower. In general, the mechanical properties of RHA concrete are higher than the control super-plasticized concrete but marginally lower than the CSF concrete. Durability of RHA concrete with regards to ISA is similar or better than CSF concrete.

DOI:

10.14359/13289


Document: 

SP221-39

Date: 

May 1, 2004

Author(s):

A. A. Ramezanianpour and A. R. Pourkhorshidi

Publication:

Symposium Papers

Volume:

221

Abstract:

It is well known that supplementary cementing materials can enhance the durability of concrete structures particularly in the hot and severe environment. In this study, concrete specimens containing different supplementary cementing materials, namely; silica fume, slag, a natural pozzolan (trass), and mixtures of cement and two pozzolans have been investigated. The tests conducted include, compressive strength, permeability, chloride diffusion, corrosion of reinforcing bars, and carbonation depth, all at different ages. The variables were cement types, supplementary cementing materials, water-cement ratio, and cover thicknesses. After standard curing, concrete specimens were transferred to the Gulf region and maintained in submerged, wetting and drying and coastal environments. For exposure to alternate cycles of wetting and drying, known as the most severe condition, the superior performance of silica fume was followed by the concrete mixture containing trass. However, all concrete mixtures containing natural or artificial pozzolans showed better performance compared with the portland cement control concrete mixtures.

DOI:

10.14359/13282


Document: 

SP221-07

Date: 

May 1, 2004

Author(s):

S. J. Barnett, M. N. Soutsos, J. H. Bungey, and S. G. Millard

Publication:

Symposium Papers

Volume:

221

Abstract:

The early age strength development of concretes containing fly ash and ground granulated blast furnace slag has been investigated in order to give guidance for their use in fast track construction. Their use in concrete, although economic, has not gained popularity in fast track construction because of the slower strength gain of these concretes at standard curing temperatures. There are however indications that these cement replacements are heavily penalised by the standard curing regimes. The continuous measurement of the in situ temperatures during a UK Concrete Society Core Project has allowed the early age strength development of concretes in full-scale structural elements to be monitored. The effects of a range of environmental conditions and structural element parameters, including cement replacements, on the early age temperature history and hence the strength development of these concretes has been quantified. High early age temperatures are shown to be especially beneficial to ground granulated blast furnace slag concretes.

DOI:

10.14359/13250


12345...>>

Results Per Page