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
Showing 1-5 of 34 Abstracts search results
Document:
SP288
Date:
October 1, 2012
Author(s):
Editor: V.M. Malhotra
Publication:
Symposium Papers
Volume:
288
Abstract:
This CD contains 33 papers presented at the Tenth International Conference of Superplasticizers and Other Chemical Admixtures in Concrete held in Prague, Czech Republic, in October 2012. Topics include Synthesis, Characterization, and Dispersing Performance of a Novel Cycloaliphatic Superplasticizer; Compatibility between Polycarboxylate and Viscosity-Modifying Admixtures in Cement Pastes; Aspects of Gypsum-Free Portland Cement; A Novel Type of PCE Possessing Silyl Functionalities; and much more. Note: The individual papers are also available. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP-288
DOI:
10.14359/51684135
SP288-24
September 14, 2012
Valeria Corinaldesi and Saveria Monosi
This paper presents the results of an investigation carried out to develop colored self-compacting concretes (SCCs), especially devoted to architectural structures. Two different inorganic pigments were tested, both at a dosage of 20 kg [44.09 lb] per cubic meter of concrete, replacing limestone filler. The first is cobalt-salt based (for blue-colored SCC), the other iron-oxide based (for red colored SCC). SCC mixtures were characterized in the fresh state by means of slump flow and V-funnel tests as well as after hardening by means of compression tests and free dying shrinkage measurements. The influence of the inorganic pigments as well as of fly ash addition on the rheological behavior of the SCCs was also previously studied by means of rheological tests on cement pastes. Low water/binder ratio (0.45) was always adopted for durability reason. Moreover, shrinkage-free SCC was studied due to the combined use of a CaO-based expansive agent and a shrinkage reducing admixture.
10.14359/51684240
SP288-25
Wolfram Schmidt, Henricus J. H. Brouwers, Hans Carsten Kuehne, and Birgit Meng
Depending upon the chemical source and the polymeric structure, stabilizing agents affect cementitious systems differently with effect on rheology and early age prop¬erties. They can also modify the effects produced by superplasticizers. Additionally, envi¬ronmental temperatures can change their effectiveness significantly, yielding adverse work¬ability properties or modified early hydration. This study presents the effects of different stabilizing agents on cementitious binder pastes exposed to varied climatic conditions during casting and early hydration. Rheological measurements show in which ways envi¬ronmental conditions affect the flow properties and the resistance to segregation. Further¬more it is demonstrated that due to interactions, the typically observed retarding effect of stabilizing agents on the setting of cementitious systems does not necessarily occur when superplasticizers based on polycarboxylate ether are present.
10.14359/51684241
SP288-20
Charles K. Nmai and Joseph A. Daczko
In 2009, an innovative admixture technology that provides flexible amounts of workability retention when used in combination with water-reducing admixtures, in partic¬ular high-range water reducers, was introduced in North America. This admixture provides slump and workability retention without impacting initial workability and with no adverse effect on time of setting or early-age compressive strength. In this paper, the use of this innovative workability-retaining admixture in several unique applications are presented and discussed. The data presented in this paper show that the workability-retaining admix¬ture can be used to provide varying degrees of slump retention as desired and, more impor¬tantly, to improve batch-to-batch consistency with respect to plastic and hardened concrete properties.
10.14359/51684236
SP288-21
Eberhard Eickschen
From some job sites it was reported that the air void content of the hardened concrete was higher than that of the fresh concrete. Investigations with commercial air-entrainers based on synthetic and natural active agents showed that a substantial increase in air content can occur only if the fresh concrete is supplied with air-entrainer that is insuffi¬cient activated. The air void content may increase if mixing energy is subsequently applied during placement or transport. The air void formation was studied as a function of the type and quantity of the admixture added and of the mixing time. Furthermore, the precipitation of admixtures in calcium hydroxide was investigated. A subsequent increase in air content is to be expected only with admixtures based on synthetic active agents due to their better solubility in the pore solution. The knowledge of the working mechanisms allows giving recommendations for practice to avoid an increase in the air content.
10.14359/51684237
Results Per Page 5 10 15 20 25 50 100
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.
Edit Module Settings to define Page Content Reviewer