Research on the Preparation of Economical Powder Concrete-UHPC

2014 ◽  
Vol 513-517 ◽  
pp. 108-112
Author(s):  
Ke Wu ◽  
Shang Chuan Zhao
Keyword(s):  
Particle Size ◽  
High Performance ◽  
High Performance Concrete ◽  
Size Range ◽  
Close Packing ◽  
Particle Size Range ◽  
River Sand ◽  
Reactive Powder ◽  
Cement Grinding ◽  
The Cost

In this paper I will introduce a new kind of powder concrete which I call it UHPC.UHPC is a kind of high performance concrete. Now the cost and the condition of ordinary powder concrete is too high. It is unfavorable to the popularization and application of powder concrete. This article mainly is to use gravel that have particle size range between 3 ~ 5 mm and particle size range between 1 ~ 3 mm and particle size range between 0.21 ~ 0.42 mm river sand .the aggregate will through the close packing to match. Gelling materials mainly use three kinds of cement. They are ordinary Portland cement 52.5, sulfur-aluminum cement, and superfine cement grinding. The appropriate ratio of gelled material will determine by the experiment. Poly carboxylic acid additive and defoaming agent will be used to configure the reactive powder concrete. Main purpose is to configure economy powder concrete in Regular maintenance condition.

scholarly journals Influence of Particle Size of River Sand on the Decontamination Process in the Slow Sand Filter Treatment of Micro-Polluted Water

Water ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 100
Author(s):  
Xuemei Ji ◽  
Cui Zhao ◽  
Yufeng Lv ◽  
Jifu Yang ◽  
Bin Li
Keyword(s):  
Particle Size ◽  
Rural Areas ◽  
Size Range ◽  
Removal Rate ◽  
Polluted Water ◽  
Adsorption Model ◽  
Particle Size Range ◽  
River Sand ◽  
Term Operation ◽  
N Removal

Slow sand filters (SSFs) have been widely used in the construction of water plants in rural areas. It is necessary to find river sand of suitable particle size to improve SSF treatment of micro-polluted water so as to ensure the effective and long-term operation of these plants. In this study, SSF1# (particle size of 0.1–0.5 mm), SSF2# (particle size of 0.5–1 mm), and SSF3# (particle size of 1–1.5 mm) were selected. The physical absorption, CODMn and NH4+-N removal effect, and microbial community were analyzed. According to Langmuir and Freundlich adsorption model fitting, the smaller the particle size of the river sand, the more pollutants are adsorbed under the same conditions. SSF1# has the shortest membrane-forming time, highest CODMn and NH4+-N removal rate, and highest Shannon estimator, indicating that there are more abundant microbial species in the biofilm. Mesorhizobium, Pannonibacter, Pseudoxanthomonas, Aquabacterium, Devosia, and other bacteria have different proportions in each system, each forming its own stable biological chain system. The effluent quality of the three SSFs can meet drinking water standards. However, river sand with a particle size range of 0.1–0.5 mm is easily blocked, and thus the recommended size range for SSF is 0.5–1 mm.

381. Sampling Efficiencies of Three Personal Aerosol Samplers within and Beyond the Inhalable Particle Size Range

2001 ◽  
Author(s):  
V. Aizenberg ◽  
P. Baron ◽  
K. Choe ◽  
S. Grinshpun ◽  
K. Willeke
Keyword(s):  
Particle Size ◽  
Size Range ◽  
Particle Size Range

scholarly journals Ultra-high-performance concrete with local high unburned carbon fly ash

DYNA ◽  
2021 ◽  
Vol 88 (216) ◽  
pp. 38-47
Author(s):  
Joaquín Abellán García ◽  
Nancy Torres Castellanos ◽  
Jaime Antonio Fernandez Gomez ◽  
Andres Mauricio Nuñez Lopez
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Unburned Carbon ◽  
High Tech ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
The Cost

Ultra-high-performance concrete (UHPC) is a kind of high-tech cementitious material with superb mechanical and durability properties compared to other types of concrete. However, due to the high content of cement and silica fume used, the cost and environmental impact of UHPC is considerably higher than conventional concrete. For this reason, several efforts around the world have been made to develop UHPC with greener and less expensive local pozzolans. This study aimed to design and produce UHPC using local fly ash available in Colombia. A numerical optimization, based on Design of Experiments (DoE) and multi-objective criteria, was performed to obtain a mixture with the proper flow and highest compressive strength, while simultaneously having the minimum content of cement. The results showed that, despite the low quality of local fly ashes in Colombia, compressive strength values of 150 MPa without any heat treatment can be achieved.

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