The variability in commercial laboratory aggregate testing for road construction in South Africa

Simple data comparisons were undertaken using project data to illustrate the need for duplicate test analyses in road construction material investigations for hard rock aggregate sources. Test data was sourced from projects commissioned by the South African National Roads Agency SOC Limited (SANRAL). All test results except the polished stone value were reported by commercial geotechnical laboratories that are accredited with the South African National Accreditation System (SANAS). Only samples subjected to duplicate test analyses were used, as this method allows direct comparisons. The tests used for comparison included the polished stone value, wet and dry versions of the Aggregate Crushing Value test, wet and dry versions of the 10% Fines Aggregate Crushing Value test, the ethylene glycol-soaked version of the 10% Fines Aggregate Crushing Value test, and the water absorption test of both the fine (-5.00 mm) and coarse (+5.00 mm) material fractions. The results show that duplicate testing is firmly justified, as test results reported were often highly variable, despite all participating laboratories being SANAS-accredited and using standardised methods. Further consideration was then given to the additional cost of duplicate testing at project stage investigations compared to the cost implications of having erroneously reported materials failing in service or having good-quality materials rejected.

Download Full-text

Retrofit and Renovation of Concrete Bridges with Fibre Reinforced Polymer (FRP): The Third Alternative

MATEC Web of Conferences ◽

10.1051/matecconf/201819909010 ◽

2018 ◽

Vol 199 ◽

pp. 09010

Author(s):

Gerrit Visser ◽

Kees Van Ijselmuijden ◽

Ernst Klamer ◽

Gideon Van Zijl

Keyword(s):

The Netherlands ◽

South African ◽

Construction Material ◽

Concrete Bridges ◽

The South ◽

Awareness Campaign ◽

Reinforced Polymer ◽

Alternative Construction ◽

Pedestrian Bridges ◽

Fibre Reinforced Polymer

This paper presents Fibre Reinforced Polymer (FRP) as a third alternative construction material worth considering when retrofitting a bridge structure. FRP offers the following advantages: lighter than steel and concrete, non-corrosive, low in maintenance, stronger than structural steel and fatigue resistant. FRP has been used in Europe and more specifically in the Netherlands for almost 20 years in the retrofitting of road bridges, in new pedestrian bridges, road bridges and lock doors for sluices. The Netherlands has recently developed the updated Dutch Design Code CUR Recommendation 96, which was published in December 2017. The CUR Recommendation 96 will form the basis for developing the Eurocode FRP which is expected to be published between 2020 and 2025. The use of FRP in retrofitting of bridges is presented using examples which demonstrate how existing concrete decks, and steel and concrete substructures could be retained by the use of FRP in the retrofitting solution. Due to FRP being a relatively unknown material within the South African bridge design field, the authors have embarked on an awareness campaign targeting academics, government bodies, suppliers, manufacturers and contractors, with the aim of presenting FRP as a third alternative construction material in the South African bridge fraternity.

Download Full-text

Physical-Chemical Characteristics of South Aceh Marble and Its Suitability for Tiles Application

Jurnal Inotera ◽

10.31572/inotera.vol5.iss1.2020.id93 ◽

2020 ◽

Vol 5 (1) ◽

pp. 1

Author(s):

Lindawati Lindawati ◽

Irwansyah Irwansyah ◽

Nuzuli Fitriadi

Keyword(s):

Water Absorption ◽

Construction Material ◽

Chemical Properties ◽

Physicochemical Analysis ◽

Building Stone ◽

Test Results ◽

Water Absorption Test ◽

Natural Stones ◽

Physical And Chemical ◽

And Chemical Properties

Marble is a metamorphic rock that is widely distributed in the Earth�s continental layer. Regarding its antiquity and aesthetic appeal, it has been widely used as a construction material such as flooring tiles in buildings and monument. Physical and chemical properties of natural stones play an important role on deciding their application area as a building stone. This study reports the physicochemical analysis of marble stones from the Gunung Kerambil (GK), Alur Kering (AK) and Meukek (M) area in South Aceh District. Density, water absorption and chemical analyses of the marble samples were determined. Physical properties of samples were determined through laboratory measurements. Chemical characterizations were made using X-ray Fluorescence (XRF) method. Based on,water absorption test results, the marbles from South Aceh are applicable for tile application.

Download Full-text

Blood and breath alcohol test results: Uncertainty at the interface of science and law

South African Law Journal ◽

10.47348/salj/v138/i3a5 ◽

2021 ◽

Vol 138 (3) ◽

pp. 535-568

Author(s):

J B Laurens ◽

P A Carstens ◽

J B Laurens ◽

L G Curlewis

Keyword(s):

Measurement Uncertainty ◽

South African ◽

Due Process ◽

Road Traffic ◽

Test Results ◽

The South ◽

Scientific Principles ◽

Process Perspective ◽

National Road ◽

Alcohol Testing

Alcohol is well known for its ability to impair human faculties, which creates risks when driving a vehicle or when performing safety- and risk-sensitive tasks in workplaces. The article aims to highlight some shortcomings in the legal-scientific approach for alcohol testing in South Africa. In particular, we investigate the measurement uncertainty of blood alcohol test results, which is critical in adjudicating over-the-limit cases. The South African regulatory framework for alcohol testing in the criminal- and private-law environments is examined from an analytical due-process perspective, considering measurement uncertainty and other well-established scientific principles which are essential at the interface of science and law. Special attention is paid to the National Road Traffic Amendment Bill, which aims to decrease the alcohol limit to zero. We found that the measurement uncertainty concept has not yet been received into the South African legal system, even though it is a well-established scientific principle. We suggest changes to the current alcohol legislation to accommodate the measurement uncertainty principle and the related likelihood ratio, which we believe could assist in quantifying the odds of compliance. In particular, we believe that our suggestions regarding quantification and reporting of measurement uncertainty can assist the courts and tribunals to avoid false-positive errors that may have a devastating effect on innocent subjects.

Download Full-text

Volatility dynamics and the risk-return relationship in South Africa: A GARCH approach

Investment Management and Financial Innovations ◽

10.21511/imfi.18(2).2021.09 ◽

2021 ◽

Vol 18 (2) ◽

pp. 106-117

Author(s):

Nitesha Dwarika ◽

Peter Moores-Pitt ◽

Retius Chifurira

Keyword(s):

South Africa ◽

Parameter Estimation ◽

South African ◽

Risk Estimation ◽

Probability Distributions ◽

Financial Data ◽

Test Results ◽

Sample Period ◽

The South ◽

Risk Return

This study is aimed at investigating the volatility dynamics and the risk-return relationship in the South African market, analyzing the FTSE/JSE All Share Index returns for an updated sample period of 2009–2019. The study employed several GARCH type models with different probability distributions governing the model’s innovations. Results have revealed strong persistent levels of volatility and a positive risk-return relationship in the South African market. Given the elaborate use of the GARCH approach of risk estimation in the existing finance literature, this study highlighted several weaknesses of the model. A noteworthy property of the GARCH approach was that the innovation distributions did not affect parameter estimation. Analyzing the GARCH type models, this theory was supported by the majority of the GARCH test results with respect to the volatility dynamics. On the contrary, it was strongly unsupported by the risk-return relationship. More specifically, it was found that while the innovations of the EGARCH (1, 1) model could account for the volatile nature of financial data, asymmetry remained uncaptured. As a result, misestimating of risks occurred, which could lead to inaccurate results. This study highlighted the significance of the innovation distribution of choice and recommended the exploration of different nonnormal innovation distributions to aid with capturing the asymmetry.

Download Full-text

The predictive validity of the selection battery used for junior leader training within the South African national defence force

SA Journal of Industrial Psychology ◽

10.4102/sajip.v29i3.119 ◽

2003 ◽

Vol 29 (3) ◽

Author(s):

Johannes Muller ◽

Johann Schepers

Keyword(s):

South African ◽

Predictive Validity ◽

Mental Stress ◽

Test Results ◽

The South ◽

Independent Variables ◽

Dependent Variables ◽

Leader Training ◽

National Defence ◽

Selection Of

The principal objective of the study was to determine the predictive validity of the test battery used for the selection of junior leaders in the South African National Defence Force. A sample of 96 respondents completed certain indices of the SPEEX-Battery as well as the Advanced Ravens Progressive Matrices test. The test results were compared with the course results. Using canonical correlation analysis, a highly significant relationship was found between the independent variables and the dependent variables (r = 0,787; p is less than 0,00005). The predictors with the highest loadings were cognitive ability, conceptualisation, reading comprehension, listening potential, physical stress, and mental stress. Opsomming Die hoofdoelwit van die studie was om die voorspellingsgeldigheid van die toetsbattery vir keuring van junior leiers in die Suid Afrikaanse Nasionale Weermag te evalueer. ’n Steekproef van 96 respondente het sekere indekse van die SPEEX-Battery asook die Advanced Ravens Progressive Matrices toets voltooi. Die toetsresultate is vervolgens vergelyk met die kursusuitslae. Die veranderlikes is aan kanoniese korrelasie-ontleding onderwerp wat ’n betekenisvolle verwantskap opgelewer het tussen die onafhanklike veranderlikes en die afhanklike veranderlikes (r = 0,787; p is kleiner as 0,00005). Die voorspellers met die hoogste ladings was kognitiewe vermoë, konseptualisering, leesbegrip, luisterpotensiaal, fisieke stres en psigiese stres.

Download Full-text

Antigenic relationship of West Nile strains by titre ratios calculated from cross-neutralization test results

Epidemiology and Infection ◽

10.1017/s0950268800068059 ◽

1987 ◽

Vol 99 (2) ◽

pp. 551-557 ◽

Cited By ~ 12

Author(s):

N. K. Blackburn ◽

D. L. Thompson ◽

P. G. Jupp

Keyword(s):

South African ◽

Prototype Strain ◽

Antigenic Relationship ◽

Test Results ◽

The South ◽

West Nile ◽

Indian Strain ◽

Relationship Of ◽

Prior Infection ◽

Prototype Virus

SUMMARYThe antigenic relationship of ten South African West Nile isolates, the South African prototype virus H442, the Egyptian strain EG101 and the Indian strain G2266 were compared using titre ratios. The titre ratios or ‘R’ values were calculated from heterologous and homologous neutralization titres and expressed as a percentage.Substantial antigenic differences were demonstrated between the South African prototype strain and the majority of the recently obtained South African isolates, seven of which were fairly closely related and possibly form a distinct antigenic sub-set. The recent isolates also differed from the Egyptian and Indian West Nile isolates. The heterologous results between the South African West Nile strains and the Indian strain G2266 suggest that prior infection with an Indian West Nile virus would give poor protection against the South African viruses, whereas the reverse would not be so.

Download Full-text