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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 40 Abstracts search results
Document:
SP217-28
Date:
September 1, 2003
Author(s):
C.-S. Shon, D. G. Zollinger, and S. L Sarkar
Publication:
Symposium Papers
Volume:
217
Abstract:
A test apparatus called "dilatometer" has been developed to predict the dosage of lithium nitrate (LiNO3) required to control ASR expansion as a function of the alkali level and aggregate reactivity. The dilatometer is instrumented so as to monitor within a short period of time the volumetric expansion of the siliceous gel produced by a siliceous aggregate. The rationality of this test procedure was explored from comprehensive laboratory experiments related to the effects of temperature, normality of NaOH test solution, and LiNO3 dosage. Determination of the level of expansion within 30 hours, using this method enables one to predict the dosage of LiNO3, which is now being used as an ASR mitigating agent, needed for a particular aggregate to control expansion due to ASR. Based on the test results, it is anticipated that this test method will be useful for predicting the optimum dosage of LiNO3 required for a particular aggregate type and source.
DOI:
10.14359/12929
SP217-29
J. Sakamoto, Y. Takaki, Y Takeichi, and S. Enomoto
This paper describes the properties of lightweight aggregate concrete consisting of high performance artificial lightweight aggregate. The concrete was developed in order to be used on a rigid frame prestressed concrete bridge with a length of 256m. The concrete had good pumpability, resistance to freezing and thawing action, and high strength. The maximum equivalent horizontal pumping distance of the concrete was more than 150m with no prewetting of the lightweight aggregate. The compressive strength of the concrete was about 6OMPa and the elastic modulus was more than 21GPa.
10.14359/12930
SP217-24
R. L Munn, G. Kao, and Z.-T. Chang
A substantial research program has been undertaken at the Australian Centre for Construction Innovation of the University of New South Wales to determine the benefits resulting from the use of permeability reducing admixtures as integral components of concrete required to demonstrate superior durability in aggressive environments. This program used commercial concretes which contained conventional water reducing admixture, different types of supplementary cementitious materials and permeability reducing admixtures at various dose rates. The program included testing of both plastic state and hardened state properties of these concretes to assess the compatability and impact on performance properties. Both concrete and mortar testing have been undertaken in order to determine a range of properties including setting time, strength, drying shrinkage, chloride resistance, and sulphate resistance. Assessment of these tests indicates that these permeability reducing admixtures can positively influence the key performance properties indicative of improved durability.
10.14359/12925
SP217-25
E. Sakai, D. Atarashi, A. Kawakami, and M. Daimon
Polymers with a shorter graft length or longer intervals of graft chains are adsorbed more easily even though the adsorption sites are decreased. The content of carboxyl groups in polymer increased with the decrease in graft chain length. The intervals between graft chains are prolonged, with changed composition of the copolymer where methoxypolyethylene is replaced by styrene or allyl sulfonates. When a larger amount of carboxyl groups was introduced on the main chain or when the distance between the graft chains was extended, the influence of inorganic electrolytes on the fluidity of the suspension with the superplasticizer was decreased. These superplasticizers can be adsorbed on limestone powder even though the adsorption sites were decreased when inorganic electrolytes were added. In contrast to the case of C032-, the addition of S042may possibly cause shrinking of the polymer chain as well as hindering the adsorption of the superplasticizer. Superplasticizers containing graft chains with longer chain length are effective for preventing the fluidity decrease when S042- is added.
10.14359/12926
SP217-26
K. Tsukada, M. Ishimori, and M. Kinoshita
Three new polycarboxylate-based liquid superplasticizers (SPI-3) and powder superplasticizers (PSPI-3), which are made from SPI-3, are synthesized and evaluated. SP3, which has two different lengths of polyoxyethylene chains in one polymer molecule, showed high cement dispersing capability, good fluidity retention and short setting time. PSP3, which is made from SP3, showed low moisture absorption and excellent antiblocking property. The results show the following properties of PSP3, compared to those of general powder type superplasticizers such as Naphthalene-based powder superplasticizer (NS) and Melamine-based powder superplasticizer (MS). 1) Necessary dosage to obtain equal fluidity is about a tenth. 2) Fluidity retention is better. 3) Setting time is shorter. 4) Compressive strength of mortar is higher. 5) PSP3 is non-formalin type superplasticizer.
10.14359/12927
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