Conference Publications

Permanent URI for this collection

http://hdl.handle.net/10204/11486

Browse

Now showing 1 - 20 of 5890

CSIR Annual report 1961
(CSIR, 1961) CSIR
In the presentation of this report, attention is directed to the research services provided by the Council for industry, local authorities, provincial administrations and government departments.
Building design for the Rhodesian climate
(CSIR Division of Building Technology, 1974-10) Van Straaten, JF; Lotz, FJ
The need for conserving energy is emphasised. Recommendations are made to ensure the best thermal performance under the relevant climatic conditions. Several construction methods are discussed against a thermal comfort scale for housing.
Collapse settlement in compacted soils
(1977) Booth, AR
Research into collapse settlement in compacted soils is described, with special reference to recent cases in Southern Africa where collapse settlement occurred in road embankments following wetting of the soil. The laboratory work described consisted largely of oedometer tests over a range of saturations, on soils from four of these road embankments, compacted in a mould especially designed for this purpose.
Miners' dictionary: English/Fanakalo
(Chamber of Mines Services, 1978) Chamber of Mines, South Africa
In simple terms Fanakalo means 'like this'. Fanakalo originated in the sugar industry of KwaZulu Natal as a result of Indians trying to learn English and Zulu at the same time. The language spread across the boarders of KZN to industries and mines and became the common language amongst mine and industry workers. This book, the first out of two books, published will help those who are passionate about learning this language.
Alternative energy sources for the heating and cooling of a building
(1979-11-27) Strydom, JFS
The objective of two of the studies was to choose the most economical source of heating energy, taking cognizance of the building owner’s particular circumstances; in both cases a suitable alternative to light petroleum oil, which had been used previously, had to be found. The third study involved the possibility of using solar energy as an alternative.
Basic principles of solar water heating
(CSIR, National Building Research Institute, 1980-09-10) Page-Shipp, RJ
This article correctly reflects the principles of Solar Water Heating as they pertain to South African conditions. However, it was written in 1980 and the global energy situation has changed considerably. Furthermore, modern commercial units will have taken many, perhaps all, of the key design aspects into account. Potential purchasers should still check on position and orientation of units, attention to insulation and corrosion and freezing resistance.
Conservation – a new and efficient source of energy
(Council of Scientific and Industrial Research, 1981-09) National Building Research Institute
Energy is becoming increasingly expensive. Conservation can offset the increase in energy cost and can therefore be considered a new and can fairly inexpensive source of energy. The following article looks at the ways in which energy savings in both new and existing buildings can be achieved.
Advances in design of air-heating collectors
(1982-11) Johannsen, A
Principles of the operation of air-heating collectors are discussed. The fundamental differences between the design principles of air-heating as opposed to water-heating collectors are highlighted. The main requirement is the transfer of heat from the solar absorber to the air with minimum thermal losses and minimum pumping power. To achieve this objective, the basic arrangement with flow of air on the shaded side of the absorber is preferred. An optimum design of the absorber-to-air heat exchanger may be obtained by providing the sided of the absorber with slotted or interrupted fins in a staggered arrangement. The design of such heat exchangers should be based on correlations for the developing flow regime in the hydrodynamic and thermal entry regions. Solar absorber to the air with minimum thermal losses and minimum pumping power. To achieve this objective, the basic arrangement with flow of air on the shaded side of the absorber is preferred. An optimum design of the absorber-to-air heat exchanger may be obtained by providing the sided of the absorber with slotted or interrupted fins in a staggered arrangement. The design of such heat exchangers should be based on correlations for the developing flow regime in the hydrodynamic and thermal entry regions.
Acceptable indoor thermal conditions and implications for energy conservation in continental climate
(1983-08) Wentzel, JD; Kok, R; Lewis, MI; Meese, GB
Discuss the indoor temperature ranges found acceptable by occupants of buildings controlled by passive means, in areas where the influence of land mass dominates the local climate
Acceptability of the integral solar water heater by householders in the low income urban community
(National Building Research Institute, 1984) Basson, FA; Jammine, E; Heyl, L
A research and demonstration project on the use and performance of low cost integral solar water heaters in urban low-income dwellings was carried out in 1982/83. The project involved technical and socio-economic components. This report summarises the socio-economic study where the reaction of respondents to the use of the integral solar water was obtained, together with data on energy costs and hot water usage.
Enhancements in the DEROB-IUA 1,0 building thermal simulation coding to improve the productivity of validation exercises
(Council of Scientific and Industrial Research, 1985-06) Higgs, FS
A series of enhancements to the DEROB-IUA 1, 0 building thermal simulation system coding which aid the advanced user of the system in validation exercises is described.
The effect of poor drainage on pavement structures studied under accelerated testing
(1987) De Beer, Morris; Horak, E
Most of the structural failures in road pavements are in one way or another associated with excess water trapped within the pavement structure owing to poor drainage. The combined effect of traffic loading and trapped water within the pavement is very destructive, particularly in the upper layers. The effect of excess porewater pressure (EPWP) was studied on several types of pavement strcutures with the aid of the South African Heavy Vehicle Simulator (HVS). The following pavement structures were tested, viz of bituminous base, cemented base, granular base and concrete base pavement structures. During the EPWP state, moisture-accelerated distress (MAD) of the pavement occurs. It was show that non-durable materials must be avoided, especially in the upper layers of the pavement structure. The measurement of permanent deformation on the surface of the pavement during HVS testing proved to be a relatively good indicator of behaviour during both dry and soaked conditions. In bituminous and concrete base structures durable subbases of adequate thickness and indispensable, whereas in cemented base and granular base structures it is essential to prevent surface water from entering through cracks in the relatively thin surfacing layers. This is accompanied by preventive maintenance and adequate drainage provision. Faulting and pumping on concrete pavement structures can also be limited by the use of durable subbase layers and concrete reinforcement to limit deflections.
Heavy Vehicle Simulator aided evaluation of overlays on pavements with active cracks
(1987-07) Viljoen, AW; Freeme, CR; Servas, VP; Rust, FC
Conventional overlay life estimates are often invalidated by the reflection of existing cracks in a pavement through an overlay. This is attributable to a lack of understanding of the factors influencing relative crack movements and their mechanisms. Inadequate knowledge of the ability of overlay techniques to tolerated induced strains originating from the discontinuities in the existing overlay pavement also contributes to the problem. This paper identifies the factors and mechanisms and illustrates their effects by means of field data from actual pavements. The South African Heavy Simulator was also used to evaluate a variety of conventional and innovative asphaltic overlays on a severely cracked concrete pavement of which the mechanisms and extent of relative crack and joint movements were determined prior to overlay placement. The results of this testing programme are discussed with special emphasis on the eability of the overlays to inhibit reflection cracking. It is believed that the improved knowledge of the parameters involved in reflection cracking will contribute to more realistic prediction models and result in more cost effective rehabilitation strategies.
Towards a classification system for the strength-balance of thin surfaced flexible pavements
(1988) De Beer, Morris; Kleyn, EG; Savage, PF
This paper deals with the development of a universal classification system for flexible pavements with thin surfacings. This classification is based on the results obtained with the Dynamic Cone Penetrometer (DCP) utilising the strength-balance concept of pavements. The pavement is classified according to its strength-balance in relation to Standard Pavement Balance Curves (SPBCs) developed for flexible pavements with relatively thin surfacing layers in South Africa. It is considered that the implementation of this universal classification system will enhance the interpretation of DCP results in general. It is further envisaged that the use of this system will not only result in the classification of pavements based on its strength-balance, but also aid in the understanding of basic pavement behaviour. Finally, it is considered that this system will also enhance existing methods of flexible pavement design, especially in the areas of greatest need such as the developing countries of southern Africa.
Temporal terrain shading
(CSIR, 1988-02) Cooper, Antony K
This paper describes a suite of programs that simulates the lighting effects of the sun or moon on the earth's surface. A digital terrain model (DTM) is typically a two-dimensional regular tessellation of some measured phenomenon, the most common being elevation; such DTMs are known as digital elevation models (DEMs). The tessellation represents an area fixed to the surface of some celestial body, normally the earth. The suite of programs described here simulates the lighting effects of the sun or the moon by taking as input a DEM, a date and a time. The suite determines the position of the sun or the moon relative to the DEM and produces as output a DTM shaded accordingly. The treatment of shadows is also discussed. The resulting DTM may be used to paint a perspective view of the original DEM to provide a more realistic representation of the area.
The South African standard for the exchange of digital geo-referenced information
(1989-04) Cooper, Antony K
Geographically referenced (geo-referenced) information consists of all information that refers to the human-environment system and that can be localized in space and time. This includes cadastral, topographic, hydrographic and statistical information. The need for standards for the exchange of digital geo-referenced information is well known. The author was a member of the project team which drafted the South African standard and is a member of the committee charged with maintaining this standard. This paper will provide a technical overview of the South African standard for the exchange of digital geo-referenced information. It will describe briefly our concepts of geo-referenced information and the relational model used, which makes the standard easy to use and update. A set of data being exchanged consists of the File Identification (a fixed length, fixed format file that identifies the data), the Global Information Section (giving general details about the data being exchanged, such as reference surface and coordinate offsets used) and the Georeferenced Information elations (containing the data being exchanged). This paper will describe these components, specifying how they cater for information on data quality, classification, non-spatial attributes, alternate spatial attributes, vector and raster data.
Performance of various modified binders in road trials and under simulated crack movement in the laboratory
(Asphalt Pavements for Southern Africa, 1989-06) Rust, FC; Servas, VP; Van Der Walt, N
The use of bitumen-rubbers and other modified binders to inhibit reflection cracking, highlighted the need to investigate the phenomena of load-associated crack movement and crack reflection and the evaluation of the field performance of modified binders. The development of the Crack-activity Meter (CAM)and its use with the Heavy Vehicle Simulator (HVS) has led to an improved understanding of crack movement behaviour. The N3 trial sections, which were built to determine the field performance of various modified binders under normal traffic, as well as initial rsults from this experiment are discussed in this paper. To date, fatigue testing under simulated crack movement in the laboratory was conducted on four of the binders used in the N3 trials. Initial results from this work, including fatigue curves of the four materials, are reported. Guidelines are suggested for the identification of sections on pavements where crack reflection problems can be expected. Models were also developed to predict crack movement from a knowledge of block sizes and structural parameters such as basin of deflection and an example of this is shown. It is also shown that these models can be used to predict the decrease in crack movement due to the overlaying of a pavement with a structural layer. It is concluded that the measurement of an analysis of crack movement can aid rehabilitation design.
Large stone asphalt mix design for heavy duty asphalt pavements
(1990-08) Rust, FC; Hugo, F; Myburgh, PA; Grobler, JE
The recent increase in traffic volumes and also axle loads on some of the major routes in South Africa has extended the traffic classes beyond the current highest design class. Additionally there is a strong lobby to increase the legal axle load to between 9 and 10 metric tonnes. There is also a tendency from overseas to use higher tyre pressures with new tyre types. One of the main reasons why the top size stone in mixtures has been limited to 26,5 mm is because the conventional mix design procedures cannot handle aggregates larger than 26,5 mm. A design method to incorporate the benefits of large stone mixes is urgently needed. Mix design, pavement design and pavement performance needs to be considered simultaneously and should not be independent functions as currently is so often the case. A mix design method must therefore be based on engineering properties, structural behaviour and long term performance.
Comparison between Falling Weight Deflectometer (FWD) and Benkelman Beam Deflection Basin Parameters and back-calculation of layer moduli
(1991) Lacante, SC; De Beer, Morris; Horak, E
Many years of experience exist in South Africa on the use and interpretation of Benkelman beam type of road surface deflection measurements with the Road Surface Deflectometer (RSD), as well as depth deflection measurements with the use of the Multi-depth Deflectometer (MDD). These measurements are mainly associated with slow moving (creep or static) loads. The development however, of the impulse load deflection technology, which better reflects deflections ar higher speeds (dynamic loading), allows comparative studies between creep and fast moving loads on pavements. This comparison is needed in order to better understand the effect of load duration on resilient behaviour of pavement systems. This study concentrates on a comparison between the deflection bowls (and its parameters) measured with the Impulse Deflectometer (IDM) and the Road Surface Deflectometer (RSD). The correlations of the deflection basin on granular pavements were higher than on cemented and asphalt base pavement structures. The IDM (impulse load) generally gives lower deflections than the RSD (creep load). It is believed, and it can be shown with rigorous theoretical analysis that the pavements dynamic characteristics, ie damping and inertia are the main reason for this behaviour. Further, poor correlations were found between the RSD and IDM back-calculated effective elastic moduli on asphalt and cemented base pavements. A better correlation, however, was found on granular base pavements. Although more detailed studies and refinement are necessary on this subject, the results presented here are viewed as a practical guide and are aimed to bridge the gap between creep load and impulse load technology on pavement structures in South Africa.
Behaviour of various rehabilitation options of a 'cracked-and-seated' semi-rigid pavement during accelerated testing in Transvaal
(1991) De Beer, Morris; Kleyn, EG; Wolff, H; Otte, JR
This paper summarises the full scale accelerated research done during the past six years with the Heavy Vehicle Simulator (HVS) belonging to the Roads Branch of the Transvaal Provincial Administration (TPA). The research concentrated on the structural behaviour of pavements incorporating lightly cementitious base and subbase layers. Special failure mechanisms were identified which include aspects such as crushing failure of deep pavements and effective fatigue of shallow pavements. Improved in-situ pavement evaluation methods such as with the Dynamic Cone Penetrometer (DCP) are also described. Detailed information regarding various rehabilitation options for there pavements are given together with their HVS performance.

Browse

Browsing Conference Publications by Issue Date

Results Per Page

Sort Options