Gradation Segregation Control in Asphalt Pavement Construction

2010 ◽  
Vol 163-167 ◽  
pp. 4492-4500
Author(s):  
Yong Li Ren
Keyword(s):  
Large Scale ◽  
Asphalt Pavement ◽  
Effective Means ◽  
Processing Technique ◽  
Poor Quality ◽  
Aggregate Gradation ◽  
New Era ◽  
Pavement Construction ◽  
Almost All ◽  
The Relationship

The segregation of gradation is believed to be one of the main causes of the premature pavement deteriorations. Much of unqualified aggregates used in asphalt pavement construction result in the segregation of gradation. The traditional aggregate handling method has the defects of poor quality in processing and low rate of qualified aggregate in result in highway construction in china. The beginning of the study is from more than 30 sections of the asphalt pavement construction, in which the sieve sizes for aggregate processing and the variation of aggregate gradation is under investigation. Found and used a set of standardized screens for aggregate processing on a large scale processing. The key of the gradation segregation control in asphalt pavement construction is the quality control of the aggregate processing, is pointed out. The relationship between the sieve sizes for aggregate handling and the standard sieve sizes which should be controlled; the relationship between the aggregate specifications and the screens for aggregate processing; and the relationship between the sort of mix and the aggregate specifications, is put forward. With application of the new aggregate processing method, almost all variation factor percent passing key controlled sieves is smaller than 2.6%. The mean surface texture depth measured from 229 inspection sites is 1.03 mm and the maximum variation factor of the texture depth is only 2.7%. The authors believe that the standardized aggregate processing technique reported in this paper is the most effective means to reduce asphalt pavement segregation and may open a new era in the realm of aggregate processing for highway constructions in China.

Why Do People Stay Poor?

2021 ◽  
Author(s):  
Clare Balboni ◽  
Oriana Bandiera ◽  
Robin Burgess ◽  
Maitreesh Ghatak ◽  
Anton Heil
Keyword(s):  
Occupational Choice ◽  
Large Scale ◽  
Choice Model ◽  
Effective Means ◽  
Threshold Level ◽  
Poverty Traps ◽  
Asset Transfer ◽  
Small Livestock ◽  
Program Costs ◽  
Almost All

Abstract There are two broad views as to why people stay poor. One emphasizes differences in fundamentals, such as ability, talent, or motivation. The other, the poverty traps view, emphasizes differences in opportunities which stem from access to wealth. To test between these two views, we exploit a large-scale, randomized asset transfer and an 11-year panel of 6,000 households who begin in extreme poverty. The setting is rural Bangladesh and the assets are cows. The data supports the poverty traps view—we identify a threshold level of initial assets above which households accumulate assets, take on better occupations (from casual labor in agriculture or domestic services to running small livestock businesses), and grow out of poverty. The reverse happens for those below the threshold. Structural estimation of an occupational choice model reveals that almost all beneficiaries are misallocated in the work they do at baseline and that the gains arising from eliminating misallocation would far exceed the program costs. Our findings imply that large transfers which create better jobs for the poor are an effective means of getting people out of poverty traps and reducing global poverty.

The Influence of Porous Asphalt Pavement Based on DEMATEL

2012 ◽  
Vol 178-181 ◽  
pp. 1333-1337 ◽  
Author(s):  
Ching Tsung Hung ◽  
Shih Huang Chen ◽  
Chia Chen Wu
Keyword(s):  
High Performance ◽  
Asphalt Pavement ◽  
Laboratory Method ◽  
Road User ◽  
Porous Asphalt ◽  
Decision Method ◽  
Drainage Capacity ◽  
Pavement Construction ◽  
The Relationship ◽  
Multiple Conditions

Taiwan position is in the subtropics, the climate is high temperature and much rains of year. Freeway mostly uses traditional dense grade in pavement construction, so the pavement could not remove water quickly in rainy day. It will deteriorate by rutting and aging, due to increasing maintenance frequency and cost. Porous asphalt pavement has high performance on road user safe and amenity in many countries. But the prescription in porous asphalt is Variable, for example, the fiber has miner and wood. Base on multiple conditions, the best performance can choice by multiple criteria decision method. This methodology needs the criteria under independent, but the real world is not. The study use Decision-Making Trial and Evaluation Laboratory method to establish the relationship in criteria. With result, the drainage capacity was the important factor in porous asphalt pavement.

scholarly journals Development of an Automated Remote Asphalt Paving Quality Control System

2018 ◽  
Vol 2672 (26) ◽  
pp. 28-39 ◽  
Author(s):  
Sicong Zhu ◽  
Xiangdi Li ◽  
Haoyang Wang ◽  
Dongxiao Yu
Keyword(s):  
Quality Control ◽  
Real Time ◽  
Monitoring System ◽  
Asphalt Pavement ◽  
Implementation Process ◽  
Plant Production ◽  
Construction Quality ◽  
Aggregate Gradation ◽  
Automatic Data ◽  
Pavement Construction

The asphalt pavement construction monitoring system presented in this paper covers two main asphalt pavement construction processes: hot mix asphalt (HMA) plant production and the laydown and compaction operation. The main architecture of the monitoring system, the development of the required hardware and the software structure, and the implementation process are presented in this paper. The system is able to perform automatic data collection and data transmission, and can automatically provide feedback to the construction site for real-time asphalt pavement construction quality control. The entire process works automatically without much human intervention and covers the entire project throughout the entire construction period in real time. The monitoring system was successfully implemented in the ZhaoMa Highway construction project in China, where it proved to be effective and reliable. The key asphalt plant production parameters, including asphalt content and aggregate gradation, were improved to a statistically significant level as shown by comparing before and after the monitoring system’s deployment. Statistical analysis between asphalt core density and laydown and compaction monitoring data, collected at 20 locations, indicated that rolling passes were highly correlated with density, whereas finishing rolling temperature and HMA laydown temperature were moderately correlated with density. These results imply that implementation of the monitoring system proposed by this paper could improve asphalt construction procedure quality control and asphalt pavement construction quality.

Experiments on spin-up and spin-down on a β-plane

1994 ◽  
Vol 271 ◽  
pp. 153-172 ◽  
Author(s):  
W. J. Jillians ◽  
T. Maxworthy
Keyword(s):  
Ocean Circulation ◽  
Large Scale ◽  
Flow Characteristics ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Homogeneous Fluid ◽  
Video Record ◽  
Homogeneous Models ◽  
The One ◽  
The Relationship

Here we study the spin-up and spin-down of a homogeneous fluid with a free surface on an experimental ‘β-plane’ and describe the important features for both cases over a range of parameters. Quantitative values are found for the velocity fields using a new image processing technique that analyses a video record of particle motion and stores the results digitally. Streamlines, pressure fields and vorticity values are found by interpolation techniques and result in a complete description of the flow characteristics. We discuss the relationship between the results of these experiments and those observed in large-scale homogeneous models of ocean circulation, e.g. Moore (1963). This study extends the work of van Heijst et al. (1990) to the case of spin-up in a rectangular container but of non-uniform depth and we note the differences to and similarities with their observations. It is related, also, to more recent results of Maas et al. (1992), who considered spin-up on a β-plane but in a tank of very different proportions to the one considered here.

scholarly journals Restriction of RAP% in HMA Based on Aggregate Gradation and Binder Properties

CivilEng ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 811-822
Author(s):  
Bharath Gottumukkala ◽  
Sudhakar Reddy Kusam ◽  
Vivek Tandon ◽  
Amaranatha Reddy Muppireddy ◽  
Ramya Sri Mullapudi
Keyword(s):  
Hot Mix Asphalt ◽  
Asphalt Pavement ◽  
Asphalt Binders ◽  
Recycled Asphalt ◽  
Aggregate Gradation ◽  
Naturally Occurring ◽  
Milling Method ◽  
Pavement Construction ◽  
Point G

The use of recycled asphalt pavement (RAP) in pavement construction reduces the project cost and helps in conserving the naturally occurring aggregates. To incorporate RAP in hot mix asphalt, it is vital to know the amount and quality of the reclaimed binder. Three new asphalt binders were selected for this investigation. RAP material from one source was blended in different proportions with VG-10 and VG-30. Penetration, softening point, G */sin δ, G * sin δ and binder fatigue life Nf (from Linear Amplitude Sweep test) values of different blends were compared. The milled RAP aggregate gradation varied from source to source due to factors such as the gradation of the mix used in the existing layer, milling method and processing of RAP material. This variability controls the use of higher proportions of RAP in new mixes. To investigate the effect of RAP gradation on the proportion of RAP that can be used in the new mix, RAP sources with different gradation (three dense and two gap gradations) were selected. The proportion of RAP that can be used for preparing mixes with these gradations varied significantly with the source of RAP, and the target gradation. In most cases, it was found that allowable RAP percentages are smaller for the gap gradations compared to those permitted for dense gradations. The proportion of RAP in a mix can be increased by selecting an appropriate gradation for a RAP source or by using a suitable RAP source for a given gradation.

Relationship between total plasma homocysteine and the risk of aneurysms – a meta-analysis

VASA ◽  
2020 ◽  
pp. 1-6
Author(s):  
Hanji Zhang ◽  
Dexin Yin ◽  
Yue Zhao ◽  
Yezhou Li ◽  
Dejiang Yao ◽  
...  
Keyword(s):  
Large Scale ◽  
Meta Analysis ◽  
Single Species ◽  
Total Plasma ◽  
Control Groups ◽  
Randomized Controlled ◽  
Randomized Controlled Studies ◽  
The Difference ◽  
The Relationship ◽  
Healthy Participants

Summary: Our meta-analysis focused on the relationship between homocysteine (Hcy) level and the incidence of aneurysms and looked at the relationship between smoking, hypertension and aneurysms. A systematic literature search of Pubmed, Web of Science, and Embase databases (up to March 31, 2020) resulted in the identification of 19 studies, including 2,629 aneurysm patients and 6,497 healthy participants. Combined analysis of the included studies showed that number of smoking, hypertension and hyperhomocysteinemia (HHcy) in aneurysm patients was higher than that in the control groups, and the total plasma Hcy level in aneurysm patients was also higher. These findings suggest that smoking, hypertension and HHcy may be risk factors for the development and progression of aneurysms. Although the heterogeneity of meta-analysis was significant, it was found that the heterogeneity might come from the difference between race and disease species through subgroup analysis. Large-scale randomized controlled studies of single species and single disease species are needed in the future to supplement the accuracy of the results.

Computer Analyses in Preventive Health Research

1967 ◽  
Vol 06 (01) ◽  
pp. 8-14 ◽  
Author(s):  
M. F. Collen
Keyword(s):  
Medical Research ◽  
Preventive Medicine ◽  
Health Research ◽  
Large Scale ◽  
Preventive Health ◽  
New Era ◽  
Large Numbers ◽  
Normal Test ◽  
Computer Analyses

The utilization of an automated multitest laboratory as a data acquisition center and of a computer for trie data processing and analysis permits large scale preventive medical research previously not feasible. Normal test values are easily generated for the particular population studied. Long-term epidemiological research on large numbers of persons becomes practical. It is our belief that the advent of automation and computers has introduced a new era of preventive medicine.

Editor’s Pick: Regulatory and Ethical Issues in the New Era of Radiomics and Radiogenomics

EMJ Radiology ◽  
2020 ◽  
Author(s):  
Filippo Pesapane
Keyword(s):  
Ethical Issues ◽  
Medical Images ◽  
Practical Significance ◽  
Innovative Technology ◽  
New Era ◽  
Naked Eye ◽  
Disease Characteristics ◽  
The Future ◽  
Using Data ◽  
The Relationship

Radiomics is a science that investigates a large number of features from medical images using data-characterisation algorithms, with the aim to analyse disease characteristics that are indistinguishable to the naked eye. Radiogenomics attempts to establish and examine the relationship between tumour genomic characteristics and their radiologic appearance. Although there is certainly a lot to learn from these relationships, one could ask the question: what is the practical significance of radiogenomic discoveries? This increasing interest in such applications inevitably raises numerous legal and ethical questions. In an environment such as the technology field, which changes quickly and unpredictably, regulations need to be timely in order to be relevant.  In this paper, issues that must be solved to make the future applications of this innovative technology safe and useful are analysed.

Contemporary Qur'anic Studies in Iran and its Relationship with Qur'anic Studies in the West

2012 ◽  
Vol 14 (1) ◽  
pp. 45-72
Author(s):  
Morteza Karimi-Nia
Keyword(s):  
Islamic Law ◽  
Human Sciences ◽  
The West ◽  
Communications Technologies ◽  
Religious Learning ◽  
The Status ◽  
Islamic Republic Of Iran ◽  
Almost All ◽  
The Impact ◽  
The Relationship

The status of tafsīr and Qur'anic studies in the Islamic Republic of Iran has changed significantly during recent decades. The essay provides an overview of the state of Qur'anic studies in Iran today, aiming to examine the extent of the impact of studies by Western scholars on Iranian academic circles during the last three decades and the relationship between them. As in most Islamic countries, the major bulk of academic activity in Iran in this field used to be undertaken by the traditional ʿulamāʾ; however, since the beginning of the twentieth century and the establishment of universities and other academic institutions in the Islamic world, there has been increasing diversity and development. After the Islamic Revolution, many gradual changes in the structure and approach of centres of religious learning and universities have occurred. Contemporary advancements in modern sciences and communications technologies have gradually brought the institutions engaged in the study of human sciences to confront the new context. As a result, the traditional Shīʿī centres of learning, which until 50 years ago devoted themselves exclusively to the study of Islamic law and jurisprudence, today pay attention to the teaching of foreign languages, Qur'anic sciences and exegesis, including Western studies about the Qur'an, to a certain extent, and recognise the importance of almost all of the human sciences of the West.

Sign in / Sign up

Export Citation Format

Share Document