Evaluating the Quality Assurance and Control of Hot-Mix Asphalt from Selected Plants in South West, Nigeria

Roads are essential necessity of every nation and it is possible that even with proper designs, the roads might not be constructed to the design standard due to poor quality assurance and control resulting in poor pavement quality. This study presents experimental results carried out on various hot - mix asphalt (HMA) samples obtained across different Asphalt plants in South West Nigeria. This was done to determine the extent to which the HMA used in the construction and rehabilitation of Nigerian roads affect their service life. Six samples of the asphalt binder (bitumen) were obtained from each plant over a period of six months and tested. The tested properties were assessed based on the level of conformance with the specifications and requirements from the FMWH General Specification (Roads and Bridges). The results revealed that HMA from plant B had a specific gravity of 1.01, penetration of 65.00 mm, softening point of 53 oC, flash point of 237.00 oC, peak Marshall Stability of 18.25 kN, flow of 3.87 mm and voids in total mixture peak value of 5.08 %. HMA from plant E had a specific gravity of 1.03, penetration of 65.00 mm, softening point of 51 oC, flash point of 239.00 oC, peak marshall stability of 18.26 kN, flow of 3.67 mm and voids in total mixture peak value of 4.99 % and these were adjudged the best in conformance with the FMWH specifications. Adequate monitoring of HMA quality for either binder or wearing courses by carrying out quality control and assurance tests is thereby recommended as it affects pavement durability and performance. Keywords: Hot-mix asphalt, quality assurance, quality control, marshall stability, flow test

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A nationwide evaluation of the prevalence of human papillomavirus in Brazil (POP-Brazil study): protocol of data quality assurance and control (Preprint)

10.2196/preprints.31365 ◽

2021 ◽

Author(s):

Jaqueline Driemeyer Correia Horvath ◽

Marina Bessel ◽

Natalia Luiza Kops ◽

Flávia Moreno Alves Souza ◽

Gerson Fernando Mendes Pereira ◽

...

Keyword(s):

Quality Control ◽

Quality Assurance ◽

Quality Indicators ◽

Sampling Errors ◽

Online Data ◽

Monitoring Visit ◽

Multicenter Clinical Trials ◽

Double Entry ◽

And Control ◽

Quality Assurance And Control

BACKGROUND The credibility of a study and its internal and external validity depend crucially on the quality of the data produced. Quality control aims to monitor sampling errors and measurements during the execution of a study and is based mainly on two pillars: planning and standardization of procedures. OBJECTIVE The present article aimed to describe the stages of quality control in the POP-Brazil study and to present an analysis of the quality indicators. METHODS Quality assurance and control included several phases and processes that were initiated with the planning of the study and continued through the development of the project; thus, all centers were trained in loco. RESULTS The data were through a structured questionnaire and collection of biological samples, both performed by more than 250 trained and certified health professionals. Furthermore, to correct possible inadequacies, all 119 centers (public health units) received at least one monitoring visit, which evaluated the professionals' performance and the process of completing the online data platform. The data were monitored daily and were audited through the double entry of data, performed by the central team. The reliability of data was analyzed through the test-retest method, comparing data from the online platform and a second application of the interview, and conducted through telephone, also by the central team. The agreement between the test and retest was considered good (kappa between 0.59 and 0.74). Large multicenter clinical trials are the basis of medical evidence-based and health-based prevention, so their design, logistics, and quality processes should always be carefully considered. CONCLUSIONS This article presents the processes and quality indicators in the POP-Brazil study that allow other studies to generate reliable data.

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