Evaluation of the effect of nonsphericity of fine aggregate particles in brownian coagulation

1981 ◽  
Vol 81 (1) ◽  
pp. 21-31 ◽  
Author(s):  
K Okuyama ◽  
Y Kousaka ◽  
A.C Payatakes
Author(s):  
Sharif Y. Gushgari ◽  
Yang Zhang ◽  
Ali Nahvi ◽  
Halil Ceylan ◽  
Sunghwan Kim ◽  
...  

Faced with limited financial resources, pavement engineers constantly seek more durable and economical technologies for road preservations and rehabilitations. Consequently, there have been many efforts to study resurfacing strategies, including various types of sealing for local roads. Among different sealing methodologies, Otta seal is a technique that has not yet been sufficiently studied in the U.S.A. For this investigation, the first Otta seal site in the state of Iowa was constructed using a double-layer Otta seal design over 6.4 km of cracked asphalt pavement. Otta seal design and construction details are documented and discussed, and test sections using various aggregates are compared for performance. The key lesson learned was that proper aggregate selection within gradation limits and aggregate spread rates were critical factors for Otta seal performance. Otta seal capability for holding loose aggregate particles and for dust control were examined, and there were indications that excessive proportion of fine aggregate particles could lead to diminished performance associated with fugitive dust emissions and unbound aggregate particles. Although the Otta seal provided a smooth surface satisfying road user and agency requirements, it did not significantly add structural capacity to the existing asphalt pavement. The findings from this study will benefit road officials and other decision makers who need to consider alternatives for resurfacing distressed low-volume asphalt roads.


2021 ◽  
Vol 268 ◽  
pp. 121123
Author(s):  
Thiago Delgado de Souza ◽  
Lucas Henrique Vieira ◽  
Alexis Jair Enríquez-León ◽  
Francisco Thiago Sacramento Aragão ◽  
Leni Figueiredo Mathias Leite

Author(s):  
Randy C. Ahlrich

Because approximately 85 percent of the total volume of hot-mix asphalt (HMA) mixtures consists of aggregates, the performance of HMA mixtures is greatly affected and influenced by properties of the aggregate blend. The angularity, shape, and texture of the aggregate particles have a significant effect on the performance of HMA mixtures by controlling the mixture's strength and rutting resistance. Rough, angular aggregates have been proved to produce higher-quality HMA pavements than smooth, round aggregates. Current aggregate tests are primarily based on experience and empirical characterization tests. A study was conducted to evaluate test methods that could be used to characterize aggregate properties that are related to HMA rutting potential of heavy-duty pavements. Specifically, FAA aggregate properties and aircraft loading conditions were addressed. The aggregate particles were characterized with the particle index (ASTM D3398), uncompacted void content for fine aggregate (ASTM C1252), modified ASTM C1252 for coarse aggregate, and unit weight and voids in aggregate (ASTM C29). The HMA mixtures were evaluated for rutting potential using the confined repeated load deformation (dynamic creep) test. The laboratory investigation indicated that the tests for particle index, uncom-pacted void content for fine and coarse aggregates, and unit weight and voids in aggregate could be used to characterize the shape and texture of aggregate particles. The study also indicated that the confined creep test could differentiate between HMA mixtures with different aggregate properties in terms of their rutting potential.


Author(s):  
Rizwan Ahmad Khan ◽  

This paper investigates the fresh and durability properties of the high-performance concrete by replacing cement with 15% Silica fume and simultaneously replacing fine aggregates with 25%, 50%, 75% and 100% copper slag at w/b ratio of 0.23. Five mixes were analysed and compared with the standard concrete mix. Fresh properties show an increase in the slump with the increase in the quantity of copper slag to the mix. Sorptivity, chloride penetration, UPV and carbonation results were very encouraging at 50% copper slag replacement levels. Microstructure analysis of these mixes shows the emergence of C-S-H gel for nearly all mixes indicating densification of the interfacial transition zone of the concrete.


1997 ◽  
Author(s):  
Gorden Videen ◽  
Ronald G. Pinnick ◽  
Dat Ngo ◽  
Qiang Fu ◽  
Petr Chylek

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Songlin Yue ◽  
Yanyu Qiu ◽  
Pengxian Fan ◽  
Pin Zhang ◽  
Ning Zhang

Analogue material with appropriate properties is of great importance to the reliability of geomechanical model test, which is one of the mostly used approaches in field of geotechnical research. In this paper, a new type of analogue material is developed, which is composed of coarse aggregate (quartz sand and/or barite sand), fine aggregate (barite powder), and cementitious material (anhydrous sodium silicate). The components of each raw material are the key influencing factors, which significantly affect the physical and mechanical parameters of analogue materials. In order to establish the relationship between parameters and factors, the material properties including density, Young’s modulus, uniaxial compressive strength, and tensile strength were investigated by a series of orthogonal experiments with hundreds of samples. By orthogonal regression analysis, the regression equations of each parameter were obtained based on experimental data, which can predict the properties of the developed analogue materials according to proportions. The experiments and applications indicate that sodium metasilicate cemented analogue material is a type of low-strength and low-modulus material with designable density, which is insensitive to humidity and temperature and satisfies mechanical scaling criteria for weak rock or soft geological materials. Moreover, the developed material can be easily cast into structures with complex geometry shapes and simulate the deformation and failure processes of prototype rocks.


Sign in / Sign up

Export Citation Format

Share Document