1887

oa Civil Engineer in South Africa - Rational design of the single surface treatment technique for road maintenance

Volume 23, Issue 8
  • ISSN : 0009-7845

 

Abstract

The single surface treatment technique is the most cost-effective means of resurfacing a surfaced road. Factors which affect the design and performance of single surface treatments are divided into controllable and non-controllable. As far as the design aspects are concerned it is concluded that the voids in a single layer of stone (single-sized) in shoulder-to-shoulder contact is of paramount importance. The principal factors affecting these voids are examined and quantified from the results of both laboratory and field investigations.


A rational design method is presented which is primarily based on the average least dimension () of the single-sized stone. The rate of stone application is shown to be dependent on both the and the flakiness of the stone. The rate of binder application, however, is dependent on the of the stone and such factors as embedment, skid resistance (texture depth of seal), wear and degradation of stone during construction and subsequent service (traffic).
A unique innovation in the design is that it gives the designer a choice between accepting a seal of shorter than average life or revising the design by choosing a larger stone tor the condition when the designed binder rate of application is less than the minimum to hold the stone in place under initial traffic.
Finally, the design method proposed is verified by examining the results of seal performance where the method was used in practice. A step-by-step example of the calculations using the proposed design method is given in the Appendix to the paper.

Die tegniek van enkeloppervlakbehandeling is die mees kostedoeltreffendste manier om 'n geplaveide pad te herdek. Faktore wat die ontwerp en werkverrigting van enkeloppervlakbehandelings beïnvloed word as beheerbaar en nie-beheerbaar geklassifiseer. Wat die ontwerpaspekte betref, is daar tot die gevolgtrekking gekom dat die ruimtes in 'n enkellaag van klip (enkelgrootte) wat skouer-teen-skouer gelê word van die uiterste belang is. Die vernaamste faktore wat 'n uitwerklng op hierdie ruimtes het is ondersoek en, uit resultate afkomstig van ondersoeke in die laboratorium en in die veld, gekwantifiseer.


'n Meetbare ontwerpmetode, hoofsaaklik gebaseer op die gemiddelde kleinste afmeting () van die enkelgrootte klip, word beskryf. Die aanwendingskoers van klip blyk afhanklik te wees van die sowel as die skilferigheid van die klip. Die aanwendingskoers van bindmiddel is egter afhankilk van die en ander faktore soos die lê, glyweerstand (tekstuurdiepte van seëllaag), slyting en degradering van klip gedurende konstruksie en daaropvolgende gebruik (verkeer).
'n Unieke verandering in die ontwerp is dat dit die ontwerper die geleentheid bied om óf 'n seëllaag met 'n korter as gemiddelde lewensduur te gebruik óf om die ontwerp te hersien en 'n groter klip te kies vir die toestand waar die ontwerpte aanwendingskoers van bindmiddel laer is as die minimum om die klip in posisie te hou onder aanvangsverkeer.
Laastens word die voorgestelde ontwerpmetode geverifieer deur die resultate van die werkverrigting van 'n seëllaag na te gaan waar dié metode in die praktyk toegepas is. 'n Voorbeeld van die berekeninge waar die voorgestelde ontwerpmetode gebruik is, word stap-vir-stap in die Bylae van die verhandeling aangegee.

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/content/civeng1/23/8/EJC24856
1981-08-01
2017-04-26

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