http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
살라스-몬토야안드레스 ( Salas-montoya Andres ),정철우 ( Chung Chul-woo ) 한국건축시공학회 2021 한국건축시공학회 학술발표대회 논문집 Vol.21 No.1
The use of recycled concrete aggregates (RCA) as a substitute for natural aggregates in new concrete produces both economic and environmental advantages. Most of the RCA applications for pavements have been primarily applied to support layers for roads and airfields. This paper summarizes a work completed at the University of Illinois in partnership with the O’Hare Modernization Program to examine the effect of coarse and fine RCA on the concrete’s fresh and hardened properties for airfield rigid pavement applications. Ten different RCA concrete mixtures were prepared with the incorporation of different percentages of RCA fines as well as replacement of cement with high volume percentages of supplementary cementitious materials such as Class C fly ash and ground granulated blast furnace slag to improve the workability and long-term properties of RCA concrete. All the mixes on this stage included 100% recycled coarse aggregates and the Two-Stage Mixing Approach was used as a mixing procedure. Based on the results obtained in the research, mixes with high percentages of recycled fine and coarse aggregates could be used for construction of airfield concrete pavements in conjunction with supplementary cementitious materials
Freeze-Thaw Resistance of Concrete using Acid-Leached Rice Husk Ash
박철우,Andres Salas,정철우,이창준 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.4
The main purpose of this research is to investigate the freeze-thaw resistance of concrete incorporating acid-leached rice husk ash. The research has been initiated because of its unique microstructural characteristic: rice husk ash maintains the original cellularstructure of rice husk that has large amount of empty space, so it has a potential possibility of reducing the air void spacing factor. Thefreeze-thaw resistance of concrete using rice husk ash is compared to that using silica fume. The result shows that the freeze-thawresistance of concrete using acid-leached rice husk ash is slightly less than that of silica fume concrete during 300 freeze-thaw cycles. When freeze-thaw cycles are extended to 600 cycles, freeze-thaw resistance of concrete using acid-leached rice husk ash isequivalent to the concrete using silica fume.
Oxidation of polystyrene aerosols by VUV-photolysis and/or ozone
Vicente, Jose Salas,Gejo, Juan Lopez,Rothenbacher, Sonja,Sarojiniamma, Sumalekshmy,Gogritchiani, Eliso,Worner, Michael,Kasper, Gerhard,Braun, Andre M. Korean Society of Photoscience 2009 Photochemical & photobiological sciences Vol.8 No.7
Aerosols of submicron polystyrene particles were oxidized by either vacuum-ultraviolet (VUV) irradiation in the presence of molecular oxygen ($O_2$) and/or by ozone ($O_3$). Different degrees of oxidation and oxidative degradation were reached by VUV-photolysis depending on radiant energy, $O_2$ and $H_2O$ concentrations in the bulk gas mixture as well as on particle diameter. The same functionalization was obtained by exposing the aerosol to $O_3$, however, oxidation, in particular oxidative degradation, was less efficient. The evolution of hydroxyl and carbonyl functions introduced was quantified by ATR-FTIR spectroscopy of filtered particles, and oxidative degradation of the polymer particles was confirmed by determining size and number of aerosol particles before and after oxidation. Efficiency analyses are based on the results of an $O_3$ actinometry and on an evaluation of the rate of absorbed photons by the aerosol particles in function of their size.