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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 34 Abstracts search results
Document:
SP119-02
Date:
September 1, 1989
Author(s):
F. D. Kinney
Publication:
Symposium Papers
Volume:
119
Abstract:
Discusses a chemical approach to dealing with returned concrete that has the potential of reducing the amount of waste in concrete production to a level unmatched by other methods. This approach allows use of concrete up to 72 hr after batching and the reduction of wash-out slurry and reclaimer debris. This two-part chemical system is comprised of a stabilizer that strongly retards the hydration of all clinker minerals and a hydration initiator or activator added to stabilized concrete prior to its placement. Data presented on commercial portland cement and individual clinker minerals treated with this system show the effects of the stabilizer and initiator on the different clinker phases and were drawn from calorimetry, x-ray diffraction, and SEM studies. Control of nucleation and nuclei growth are proposed as the mechanism by which the chemical system works. Data from field-batched mixes demonstrate that the plastic and hardened properties of concrete made using this chemical system are no different than those of conventionally batched concrete.
DOI:
10.14359/2389
SP119-03
A. J. Ulshizer, J. J. Ucciferro and G. E. Gray
Describes the expanded achievements possible in concrete placements with the aid of superplasticizers and identifies the importance of preplacement testing and planning to determine structural performance and placing characteristics and limitations. Diff
10.14359/2399
SP119-04
K. Mitsui, H. Kasami, Y. Yoshioka, and M. Kinoshita
Gives results of laboratory investigations to determine the effect of a slump-retaining-type high-range water reducer. Various effects such as temperature, mix proportions, and admixture dosages on rheological and mechanical properties of concrete before and after hardening of concrete were examined. Slump, air content, and flow were tested after mixing. Setting time and bleeding were also measured. The hardened concrete was tested for strength, modulus of elasticity, shrinkage, and durability. The results indicated that it was possible to produce workable high-strength concrete and retain its workability by the admixture better than conventional superplasticizers. Higher temperature at mixing resulted in the retention of high workability. Too much admixture delayed the setting time, while no other adverse effects were noticed on mechanical properties of hardened concrete.
10.14359/2409
SP119-05
E. Ista and A. Verhasselt
In addition to a quickly obtained distinction between plasticizer and superplasticizer by means of a deflocculation test, it seems useful to complete this information by identifying their nature and chemical composition. Infrared spectrography, emission spectrometry, and wet chemical methods were applied to characterize various plasticizers. Methods employed were found to distinguish easily the various types of potential composition for such materials. They are therefore useful not only in establishing conformity of an admixture to previously submitted samples but also can discover the presence of potentially deleterious components.
10.14359/2420
SP119-06
J. Khorami and P. C.
Presently, most of the commercial superplasticizers used in concrete are characterized by their chemical formulation (melamine or naphthalene), their specific gravity, and their solid content. However, from a practical point of view, it is observed that t
10.14359/2430
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