scholarly journals The Variability and Evaluation Method of Recycled Concrete Aggregate Properties

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Zhiqing Zhang ◽  
Bozhao Shen ◽  
Hui Ren ◽  
Jin Wang ◽  
Shiyun Li ◽  
...  
Keyword(s):  
Euclidean Distance ◽  
Evaluation Method ◽  
Evaluation Model ◽  
Physical And Mechanical Properties ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Distance Method ◽  
Euclidean Distances ◽  
Mean Variance ◽  
Property Index

With the same sources and regeneration techniques, given RA’s properties may display large variations. The same single property index of different sets maybe has a large difference of the whole property. How shall we accurately evaluate the whole property of RA? 8 groups of RAs from pavement and building were used to research the method of evaluating the holistic characteristics of RA. After testing and investigating, the parameters of aggregates were analyzed. The data of physical and mechanical properties show a distinct dispersion and instability; thus, it has been difficult to express the whole characteristics in any single property parameter. The Euclidean distance can express the similarity of samples. The closer the distance, the more similar the property. The standard variance of the whole property Euclidean distances for two types of RA is Sk=7.341 and Sk=2.208, respectively, which shows that the property of building RA has great fluctuation, while pavement RA is more stable. There are certain correlations among the apparent density, water absorption, and crushed value of RAs, and the Mahalanobis distance method can directly evaluate the whole property by using its parameters: mean, variance, and covariance, and it can provide a grade evaluation model for RAs.

scholarly journals Convergence of daily mean coordinates of precise positioning methods

2021 ◽  
Vol 929 (1) ◽  
pp. 012014
Author(s):  
D V Kenigsberg ◽  
Yu M Salamatina ◽  
O A Prokhorov ◽  
S I Kuzikov
Keyword(s):  
Euclidean Distance ◽  
The Other ◽  
Local Reference Frame ◽  
Relative Precision ◽  
Distance Method ◽  
Local Reference ◽  
Euclidean Distances ◽  
Coordinates Transformation ◽  
Better Than

Abstract As part of the research of modern movements of the Earth’s crust, an analysis of 7 high-precision methods for calculating GNSS positions was carried out for the convergence of their daily mean coordinates. Based on Euclidean distances, regular and maximal discrepancies between coordinates of different methods are given. According to the coordinates in the ITRF, 5 methods are stood out with regular coordinate discrepancies <1 mm, and individual maximum discrepancies up to 30 mm. The other two methods have regular discrepancies in coordinates up to 2 cm, and the maximum differences reach 1 m. For a group of stations global coordinates transformation into a local reference frame leads to the effect of coordinate stabilization and increases their relative precision in the time series. As a result of such procedure, the level of maximum coordinate discrepancies between the methods decreased to 46%. Moreover, one of the methods of calculating coordinates has improved its convergence with the other methods by 80%. Based on the Euclidean distance method, the quality of the raw data for each station was evaluated. Thus, there is a group of 8 stations, for which the convergence of coordinates in different methods are approximately at the same level, and 2-3 times better than for the other 2 stations.

scholarly journals The Impact of Recycled Concrete Aggregate on the Stiffness, Fatigue, and Low-Temperature Performance of Asphalt Mixtures for Road Construction

2020 ◽  
Vol 12 (10) ◽  
pp. 3949 ◽  
Author(s):  
Aleksandar Radević ◽  
Ivan Isailović ◽  
Michael P. Wistuba ◽  
Dimitrije Zakić ◽  
Marko Orešković ◽  
...  
Keyword(s):  
Low Temperature ◽  
Environmental Sustainability ◽  
Construction Materials ◽  
Physical And Mechanical Properties ◽  
Asphalt Mixtures ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Road Asphalt ◽  
The Impact

The need for road (re)construction materials is constantly growing. At the same time, there is a limited quantity of new, high-quality materials available and a buildup of secondary/recycled construction materials. One possible solution may be the use of recycled concrete aggregate (RCA) in asphalt mixtures instead of natural aggregate (NA), which also promotes economic and environmental sustainability. The potential use of fine and coarse RCA in road asphalt mixtures is analyzed in this work. Nine asphalt mixtures were tested for base course layers, where RCA was used as a NA substitute. The impact of the quantity of RCA (up to 45% by mass) on the resulting physical and mechanical properties of asphalt mixtures was investigated, and consequently compared with the properties of a reference control mixture produced with NA only. Results reveal that the addition of RCA requires higher bitumen in comparison to the control mixture (up to 1%). Consequently, mixtures with RCA had 15−20% lower stiffness and up to 26% higher critical fatigue strain value (ε6). Although RCA mixtures contained more bitumen, their low-temperature resistance was slightly inferior compared with the control mixture (failure temperatures were up to 4.3 °C higher). In conclusion, asphalt mixtures with up to 45% RCA can be used without substantially reducing performance.

Properties of Dry-Mortar with Recycled Concrete Aggregate and Powder of Crushed Clay Bricks

2011 ◽  
Vol 374-377 ◽  
pp. 1637-1640
Author(s):  
Jian Hua Xue ◽  
Xiao Guang Li ◽  
Yun Xiao Liu ◽  
Qiang Du
Keyword(s):  
Compressive Strength ◽  
Physical And Mechanical Properties ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Mass Ratio ◽  
Clay Brick ◽  
Natural Sand ◽  
Clay Bricks

Recycled concrete aggregate (RCA) and crushed clay bricks (CCB) have been increasingly researched and used in past two decades. However, studies focusing on the properties of dry-mortar with RCA and CCB are very limited. In this research, results from physical and mechanical properties of recycled mortar with fine recycled aggregate (FRA), fine recycled powder (FRP) and crushed clay brick (CCB) were secured. It is shown that sinking degree of FRA mortar can be adjusted in the range of 70-90mm and their water-maintainability is superior to natural sand mortar. However, compressive strength of FRA mortar at various ages decrease, compared to natural sand mortar under the condition of same mixed proportion. Compressive strength of FRA mortar is above 5.0MPa with mass ratio of aggregate to cement lower than 6.0.Workability of FRP and CCB mortar is similar to fly ash mortar and their apparent densities are under the 2.0g/cm3. Compressive strength of FRP and CCB mortar is near to 8.5 MPa at 28 days of age.

scholarly journals Recycling Aggregates for Self-Compacting Concrete Production: A Feasible Option

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 868 ◽  
Author(s):  
Rebeca Martínez-García ◽  
M. Ignacio Guerra-Romero ◽  
Julia M. Morán-del Pozo ◽  
Jorge de Brito ◽  
Andrés Juan-Valdés
Keyword(s):  
High Performance ◽  
Physical And Mechanical Properties ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Concrete Aggregate ◽  
Structural Elements ◽  
The European Union ◽  
Self Compacting Concrete ◽  
Concrete Production ◽  
Complex Structural

The use of construction and demolition wastes (C&DW) is a trending future option for the sustainability of construction. In this context, a number of works deal with the use of recycled concrete aggregates to produce concrete for structural and non-structural purposes. Nowadays, an important number of C&DW management plants in the European Union (EU) and other countries have developed robust protocols to obtain high-quality coarse recycled aggregates that comply with different European standards in order to be used to produce new concrete. The development of self-compacting concrete (SCC) is another way to boost the sustainability of construction, due to the important reduction of energy employed. Using recycled aggregates is a relatively recent scientific area, however, studies on this material in the manufacture of self-compacting concrete have proven the feasibility thereof for conventional structural elements as well as high-performance and complex structural elements, densely reinforced structures, difficult-to-access formwork and difficult-to-vibrate elements. This paper presents an original study on the use of coarse recycled concrete aggregate (CRA) to obtain self-compacting concrete. Concrete with substitution ratios of 20%, 50% and 100% are compared with a control concrete. The purpose of this comparison is to check the influence of CRA on fresh SCC as well as its physical and mechanical properties. The parameters studied are material characterization, self-compactability, compressive strength, and tensile and flexural strength of the resulting concrete. The results conclude that it is feasible to use CRA for SCC production with minimal losses in the characteristics.

scholarly journals Analysis of Braycurtis, Canberra and Euclidean Distance in KNN Algorithm

SinkrOn ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 74 ◽  
Author(s):  
Annisa Fadhillah Pulungan ◽  
Muhammad Zarlis ◽  
Saib Suwilo
Keyword(s):  
Euclidean Distance ◽  
Evaluation Method ◽  
Nearest Neighbor ◽  
Distance Matrix ◽  
Training Data ◽  
Distance Functions ◽  
Classification Model ◽  
K Nearest Neighbor ◽  
Distance Method ◽  
Canberra Distance

Classification is a technique used to build a classification model from a sample of training data. One of the most popular classification techniques is The K-Nearest Neighbor (KNN). The KNN algorithm has important parameter that affect the performance of the KNN Algorithm. The parameter is the value of the K and distance matrix. The distance between two points is determined by the calculation of the distance matrix before classification process by the KNN. The purpose of this study was to analyze and compare performance of the KNN using the distance function. The distance functions are Braycurtis Distance, Canberra Distance and Euclidean Distance based on an accuracy perspective. This study uses the Iris Dataset from the UCI Machine Learning Repository. The evaluation method used id 10-Fold Cross-Validation. The result showed that the Braycurtis distance method had better performance that Canberra Distance and Euclidean Distance methods at K=6, K=7, K=8 ad K=10 with accuracy values of 96 %.

A Study on the Effect of Surface-Treated Coarse Recycled Concrete Aggregate (RCA) on the Compressive Strength of Concrete

2014 ◽  
Vol 935 ◽  
pp. 184-187 ◽  
Author(s):  
Sallehan Ismail ◽  
Ramli Mahyuddin
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Physical And Mechanical Properties ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Experimental Works ◽  
Compressive Strength Of Concrete ◽  
Coarse Recycled Concrete Aggregate ◽  
Effect Of Surface

This paper reports the experimental works performed to improve the properties of recycled concrete aggregate (RCA) by using different acid molarities at low concentration as agent for surface treatment. The effects of using RCA after treatment on the improvement in the strength of concrete were evaluated and compared. The findings reveal that this treatment can enhance the physical and mechanical properties of RCA. Moreover, treated RCA particles can significantly promote surface contact between the new cement paste and the aggregate, thereby improving the strength of concrete.

scholarly journals Durability of Structural Recycled Aggregate Concrete Subjected to Freeze-Thaw Cycles

2020 ◽  
Vol 12 (16) ◽  
pp. 6475 ◽  
Author(s):  
Caroline Santana Rangel ◽  
Mayara Amario ◽  
Marco Pepe ◽  
Enzo Martinelli ◽  
Romildo Dias Toledo Filho
Keyword(s):  
Physical And Mechanical Properties ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Demolition Waste ◽  
Aggregate Concrete ◽  
Damage Level ◽  
Freeze Thaw

The increasing global demand for natural resources and the extensive production of construction and demolition waste (CDW) raise concerns for both the economic and environmental consequences that they can induce. Several efforts are being made with the aim to promote sustainable practices in the construction industry. In this context, one of the most relevant options refers to reusing CDW in new construction: specifically, the use of recycled concrete aggregate (RCA) is attracting a growing interest. Unfortunately, although the behavior of recycled aggregate concrete (RAC) has been widely investigated in the last few years, there are still knowledge gaps to fill on various aspects of the RAC performance, such as its durability in extreme conditions. The present study deals with the freeze-thaw performance of normal- (C35) and high-strength (C60) RAC produced with RCAs derived from different sources. Specifically, ten concrete mixtures were subjected to a different number of freeze-thaw cycles (namely, 0, 150 and 300), with the aim of analyzing the degradation of key physical and mechanical properties, such density, compressive strength, elastic modulus and tensile strength. Based on the obtained experimental results, a novel degradation law for freeze-thaw cycles is proposed: it unveils a relationship between open porosity of concrete, which is directly correlated to the peculiar properties of RCAs, and the corresponding damage level determined on RAC specimens.

Study on the Workability and Mechanical Properties of Recycled Aggregate Concrete Containing Ultra-Fine Fly Ash

2006 ◽  
Vol 302-303 ◽  
pp. 314-320
Author(s):  
Yi Jin Li ◽  
Shi Qiong Zhou ◽  
Jian Yin ◽  
Jun Li
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Physical And Mechanical Properties ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Engineering Properties ◽  
Concrete Aggregate ◽  
Wide Range ◽  
Concrete Recycling

The subject of concrete recycling is regarded as very important in the general attempt for sustainable development in our times. Due to a wide range of variability of engineering properties for recycled concrete, a large number of experiments are usually required to decide a suitable mixture. Within the scope of this study, 13 different concrete mixtures were manufactured. The amount of recycled concrete aggregate (RCA) were 0 %, 20 %, 40 %, 60 %, 80 %, and 100 %, respectively. The replacement levels of ultra-fine fly ash are 0 %, 15 %, 25 %, 35 % and 50 %, respectively. The physical and mechanical properties along with their workability of concrete produced with RCA and ultra-fine fly ash were investigated. The experiment results showed that ultra-fine fly ash replacement had an important effect on performance of concrete with different amount of RCA.

A fuzzy evaluation method of road vehicle automatic weighing instrument in dynamic force metrological performance

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1365-1372
Author(s):  
Xiaohui Mao ◽  
Liping Fei ◽  
Xianping Shang ◽  
Jie Chen ◽  
Zhihao Zhao
Keyword(s):  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Evaluation Model ◽  
Dynamic Performance ◽  
Dynamic Force ◽  
Fuzzy Evaluation ◽  
Road Vehicle ◽  
Evaluation Standard ◽  
The Road ◽  
Metrological Performance

The measurement performance of road vehicle automatic weighing instrument installed on highways is directly related to the safety of roads and bridges. The fuzzy number indicates that the uncertain quantization problem has obvious advantages. By analyzing the factors affecting the metrological performance of the road vehicle automatic weighing instrument, combined with the fuzzy mathematics theory, the weight evaluation model of the dynamic performance evaluation of the road vehicle automatic weighing instrument is proposed. The factors of measurement performance are summarized and calculated, and the comprehensive evaluation standard of the metering performance of the weighing equipment is obtained, so as to realize the quantifiable analysis and evaluation of the metering performance of the dynamic road vehicle automatic weighing instrument in use, and provide data reference for adopting a more scientific measurement supervision method.

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