ACI Global Home Middle East Region Portal Western Europe Region Portal
Email Address is required Invalid Email Address
In today’s market, it is imperative to be knowledgeable and have an edge over the competition. ACI members have it…they are engaged, informed, and stay up to date by taking advantage of benefits that ACI membership provides them.
Read more about membership
Learn More
Become an ACI Member
Topics In Concrete
Home > Publications > 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.
Showing 1-5 of 60 Abstracts search results
Document:
SP178
Date:
June 1, 1998
Author(s):
Editor: V.M. Malhotra
Publication:
Symposium Papers
Volume:
178
Abstract:
SP-178 This Symposium Publication contains the proceedings of the Fourth CANMET/ACI/JCI International Conference held in Tokushima, Japan, in June 1998. Sixty-two refereed papers were accepted for presentation at this conference and for this publication.
DOI:
10.14359/14171
SP178-01
P. K. Mehta
Among the major problems facing the concrete industry at the end of the twentieth century are the enormous infrastructural needs of a rapidly urbanizing world, the premature deterioration of many concrete structures, the need to improve concrete durability in a cost-effective way, and increasing public interest in finding ecological solutions for safe disposal of millions of tons of industrial by-products that might be suitable for incorporation into cementitious materials and concrete. In this paper the author has shown that all these problems are interrelated and can be resolved by adopting a holistic approach.
10.14359/5969
SP178-02
K.E. Hassan and J.G. Cabrera
Waste materials may be upgraded to specification standards and occasionally to premium materials for use in the preparation of composites or for use in their own. The treatment for upgrading is a matter of cost and of the potential environmental problems that the treatment can create. The investigation presented in this paper shows an example of the improvements of fly ash properties achieved by a simple physical process, that is, air cyclone separation. This process gives a very line ash with adequate pozzolanic activity and is suitable for producing high performance concrete with excellent durability particularly when exposed to aggressive environments. The paper presents data on the properties of the fine fly ash including lime reactivity, composition, size distribution and shape. The investigation was carried out using two fly ashes obtained by the process of air separation using a prototype small air cyclone separator and an air mini-splitter. The properties of these ashes were compared to the properties of the original raw ash and with the properties of a fly ash processed industrially by the conventional mechanical separation process, which produces a fly ash conforming to the appropriate British specifications for use in the production of structural concrete. In this test programme, high performance concrete made with 0.3 fly ash and 0.7 ordinary Portland cement (by weight) as binder was assessed by measuring strength, porosity, and permeability. These properties were used to evaluate the performance of concrete and potential long term durability.
10.14359/5970
SP178-52
J. Pera and J. Ambroise
This paper presents a research carried out to convert paper sludges from de-inking and water-treatment processing plants into a pozzolanic product usable in the cement and concrete industries. Paper sludges contain inorganic fillers like ground limestone, kaolinite, clay, and organics. The process consists in heat treatment in the range of 600 to 700°C in order to transform the kaolinite present in the sludge into metakaolinite, a very reactive pozzolan, without the formation of large amounts of free lime (due to the decarbonation of the calcite also present in the sludge). In addition, the organic compounds in the sludge must be burned off and their presence reduces the use of fossil fuels to reach the temperature needed for processing. The results of both laboratory and field tests show the feasibility of the process. A reactive pozzolan is obtained when the amount of kaolinite present in the sludge is higher than 20 % of the dry inorganic phase. This metakaolin is sometimes more reactive than that obtained by calcining pure kaolinic clays, and can be used to enhance the durability of concrete in severe environments.
10.14359/6020
SP178-53
R.E. Rodriguez-Camacho
Concrete in contact with a sulfate environment can severely degrade due to expansion accompanying the formation reaction products such as ettringite. The use of Portland-pozzolan cement has been successful in mitigating this expansion. However, it is important to study the effectiveness of natural pozzolans to improve the resistance to attack by sulfates. This paper reports results of different portland-pozzolan cements containing different natural pozzolans and ASTM Types I, II, and V portland cements. The pozzolanic activity and composition of each pozzolan was evaluated. The susceptibility to sulfate attack was studied by measuring the expansion in mortar bars at different ages according to ASTM Method 1012 for 78 weeks. It was found that cements containing pozzolans with high activity or low alumina content improved the sulfate resistance. Also, the pozzolan content in the cement was found to be important.
10.14359/6021
Results Per Page 5 10 15 20 25 50 100
Edit Module Settings to define Page Content Reviewer