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 55 Abstracts search results
Document:
SP199
Date:
June 1, 2001
Author(s):
V.M. Malhotra
Publication:
Symposium Papers
Volume:
199
Abstract:
Conditioning coal-burning power-plant flue gases with ammonia reduces the emission of nitrous oxide compounds. But the ammonia often combines with available sulfur and other compounds that attach to the fly ash. If the ammoniated fly ash is then used in concrete, the high-pH environment causes a release of ammonia and a strong, objectionable ammonia smell. This can make the fly ash unmarketable. What’s the solution? Fly ash beneficiation processes that can remove ammonia and also reduce the unburned carbon content. Some of the processes are described in one of the 54 papers included in ACI SP-199, Seventh CANMET/ACI International Conference on Fly Ash, Silica Fume, Slag and Natural Pozzolans in Concrete. Other papers deal with effects of fly ash and admixture combinations on setting time, use of slag concrete to reduce corrosion of reinforcement, and the role of chemical and mineral admixtures in concrete made with recycled concrete as aggregate. Note: The individual papers are also available as .pdf downloads.. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP199
DOI:
10.14359/14006
SP199-38
J. Pera and J. Ambroise
Two silica-manganese slags containing about 11 % MnO were ground to Blaine finenesses of 360 to 600 m*/kg. Their C/S (CaO/SiO2) modulus was very low (0.47 to 0.58) and, for this reason, these slags were considered likely to be unsuitable for use in the preparation of blended cements. They were therefore introduced in concrete instead of either fly ash or silica fume. The cement content of these concrete mixtures was in range of 2 1 0 kg/m3 t o 4 5 0 kg/m3. The quantity of each supplementary cementing material was adjusted according to the French standards and varied from 50 to 80 kg/m3. The slags behaved as well in concrete as fly ash or silica fume: no decrease in strength was observed and the water permeability was the same.
10.14359/10541
SP199-39
K. 0. Ampadu, Kazuyuki Torii, and Takashi Kubota
Synopsis: Ecocement is a new type of hydraulic cement made from incinerator ashes. In this study, the effect of blast-furnace on the corrosive behaviour of steel bars embedded in mortars made from two types of ecocement; rapid hardening type with high chloride content, and NPC type with low chloride content, was investigated. Cement-slag mortars were prepared with both types of cement. The mortar specimens, with mild steel and stainless steel bars embedded, were placed in an environmental chamber under severe saline conditions. The corrosion of the mild steel bars was monitored by electro-chemical measurements. Chloride concentration profiles in cylindrical mortar specimens were also measured after the exposure period. The results of the various tests clearly indicate the beneficial effect of slag on the time of corrosion initiation and the degree of corrosion of the steel bars.
10.14359/10542
SP199-44
H. Justnes and T. Ostnor
Amorphous silica with high whiteness decomposing the basic mineral olivine, solution of magnesium and ferrous salt washing and filtering or decanting. And (Mg s and surface can be produced by simply Fe)SiO2 in any acid. The result is a silica slurry that can be purified by Such silica has been produced by treating an olivine mineral residue, a by-product of nickel ore recovery, by hydrochloric acid. The free flowing silica residue, after drying at 105C, is proven to have pozzolanic activity (consumption of calcium hydroxide) by thermal analysis (DTA/TG) and by strength measurements of mortars where cement is replaced with silica. The reactivity and strength gain was comparable to conventional silica fume obtained from ferrosilicon plants. The abundant mineral olivine can be a valuable source of amorphous silica for concrete technology, while the waste product lye could be used as a CO2 free magnesium chloride source for magnesium metal production, after purification. The process could also use waste acids, from paper pulp industry.
10.14359/10547
SP199-45
J. Paya, J. Monzo M. V. Borrachero, A. M. Mellado, and L. M. Ordonez
Different non-aqueous solvents (NAS), such as ethylene glycol, 1,2-propylene glycol and glycerol, were tested in the study of the behavior of NAS/SiOz-rich pozzolans (rice husk ash, RHA, and silica fume, SF). Dissolved SiOa in NAS/pozzolan mixtures was evaluated by several procedures: a) electrical conductivity measurements of the suspension; b) weighing of non-dissolved matter in reflux conditions; and c) titration using barium hydroxide solution. The obtained results were compared to those obtained by the reference method (solubility in boiling KOH solution). A good correlation between data obtained in NAS and the reference method was observed.
10.14359/10548
Results Per Page 5 10 15 20 25 50 100
Edit Module Settings to define Page Content Reviewer