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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 48 Abstracts search results
Document:
SP200-19
Date:
June 1, 2001
Author(s):
H. A. Razak and H. S. Wong
Publication:
Symposium Papers
Volume:
200
Abstract:
High strength concrete mixtures containing 10% metakaolin replacement and 10% metakaolin addition, water/cementitious material ratio of 0.3 and 1% super-plasticizer were studied.. Similar mixtures incorporating silica fume were also prepared. The effect of mineral admixtures on the fresh and hardened properties of concrete was investigated. Mixtures with mineral admixture exhibited lower workability, less bleeding, and slightly lower air content. Metakaolin resulted in a higher loss of workability compared with silica fume. Mixtures incorporating mineral admixture developed greater compressive strength and elastic modulus at all ages. The enhancement was more pronounced at early ages and in the addition mixtures. The study concludes that the performance of metakaolin is equivalent to silica fume in terms of contribution to the enhancement of strength and elastic modulus. The metakaolin addition mixture attained 70% and 50% strength improvement while the metakaolin replacement mixture achieved 67% and 39% strength increment at the respective ages of 3 and 28 days.
DOI:
10.14359/10586
SP200-20
T. Horiguchi, H. Okumura, and N. Saeki
bleeding; bottom ash; CLSM; compressive strength; deterioration; durability; flowability; fly ash; freezing and thawing; frost heaving; mix proportioning; slump flow; used foundry sand
10.14359/10587
SP200-21
T. R. Naik, R. N. Kraus, and S. S. Singh
This work was conducted to develop two types of controlled low strength materials (CLSM) or flowable slurry utilizing post-consumer glass (broken glass or glass cullet) aggregate and fly ash. Type A CLSM consisted of glass, fly ash, cement, and water; and Type B CLSM consisted of glass, sand, cement, and water. All mixtures were proportioned to achieve the 28-day compressive strength of 0.7 MPa (100 psi). The Type A CLSM mixtures consisted of a control mixture (100% fly ash without glass) and five other mixtures with glass, as a replacement of fly ash in the range of 20 to 80 percent. The Type B CLSM mixtures were composed of a control mixture (without glass) and two other mixtures at 30 to 75 percent replacement of sand with glass. The flowable slurry developed in this project satisfied the ACI Committee 229 definition of CLSM. Decreasing the amount of fly ash and increasing the glass content led to increased bleeding and segregation at high replacement levels of 60% and 80%. Permeability of Type A CLSM remained essentially unchanged except at high glass contents it was lower. For Type B CLSM, the permeability was about the same.
10.14359/10588
SP200-22
J. Ambroise and J. Pera
This paper deals with the development of self-levelling concrete at low cost for casting slabs and other horizontal structures. The 28-day compressive strength of such concrete is in the range of 25 to 40 MPa, and its cost is 15 % higher than that of usual concrete. This overcost is offset by some advantages: quicker execution, absence of noisy vibration at job-site and reduced painful task for workers. The cement content for this concrete ranges from 260 to 380 kg/m’, and that of limestone powder from 20 to 140 kg/m3, in order to get a total amount of fine particles of 400 kg/m3. To prevent segregation, a viscosity agent - a suspension of modified starch - was introduced in the mixture at different contents. The following characteristics were measured: static spread of concrete, unit weight, bleeding, resistance to segregation, compressive strength, elastic modulus and shrinkage. The results show that the optimum dosage of viscosity agent is 2 kg/m3, regardless of the amount of cement.
10.14359/10589
SP200-09
W. S. Langley and E. Brown
Alkali-aggregate reactivity, a reaction between the alkalies in the concrete pore fluid and certain siliceous aggregates was identified as a cause of disruptive expansion in concrete in Nova Scotia in 1962. Powerhouse structures, constructed with concrete containing meta-sediments and biotite schists which are commonly used as concrete aggregate in Nova Scotia, caused expansion which created problems with the operation of the plants within 10 years after construction. Extensive studies in the mid 1960’s and late 1980’s of operating quarries and deteriorated structures, indicated that the reactive aggregates were widespread. Studies in the 1980’s on the use of low calcium fly ash as a replacement or addition for portland cement showed conclusively that the reaction could be ameliorated with 15 to 30 percent fly ash replacement of the cement. Low calcium fly ash is now used systematically to lessen the potential for alkali-aggregate reaction.
10.14359/10576
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