See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/271707340 Searching for an optimal technical solution and concrete mixture for erosion prevention in dam slides Conference Paper · September 2007 CITATIONS READS 0 57 4 authors , including: Andrej Kryzanowski Miko š Matja ž University of Ljubljana University of Ljubljana 25 PUBLICATIONS 129 CITATIONS 535 PUBLICATIONS 2,058 CITATIONS SEE PROFILE SEE PROFILE Igor Planinc University of Ljubljana 80 PUBLICATIONS 1,234 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Longitudinal study in competency potential of university graduates and a gap between graduates' competences and labour market requirements in technology, education and health”. View project Pro ž nost alpskih pokrajin z vidika naravnih nesre č = Resilience of Alpine Environment from the Perspective of Natural Hazards View project All content following this page was uploaded by Miko š Matja ž on 03 February 2015. The user has requested enhancement of the downloaded file.
Searching for an optimal technical solution and concrete mixture for erosion prevention in dam slides A. Kryžanowski & M. Mikoš & I. Planinc University of Ljubljana, Faculty of civil and geodetic engineering, Ljubljana, Slovenia J. Šušterši č IRMA Institute, Ljubljana, Slovenia ABSTRACT: In the paper the phenomenon of abrasion of concrete in hydraulic structures is analysed, which is caused by the abrasion process resulting from the sediment carried by water. In detail the adequacy of the laboratory procedure for definition of the level of abrasion of concrete in the standard ASTM C 1138 hydrau- lic structures was investigated. This was assessed based on a comparison between laboratory results and measurements of abrasion resistance of concrete under natural conditions by performing test plots in the still- ing basin of the Vrhovo HPP. The concrete built into the evacuation structures of the HPP`s on the Lower Sava River was tested for adequacy. The basic composition of concretes was modified by additives of the ce- ment binder, steel fibres and PP fibres, and rubber aggregate. The analysis has shown a qualitative similarity of the level of abrasion of concrete between laboratory simulation and measurements in the field. The quanti- tative comparison of results has shown a good correlation between the laboratory measurements and meas- urements in the natural environment for concrete at 900-day age, while for concrete at 90-day age this correla- tion cannot be confirmed. 1 INTRODUCTION At this phase, the abrasion process depends on bed load transport or suspended matter. Besides the milling action of concrete surfaces, damage due to Damage of concrete surfaces under water impacts of solid particles against the surface can be caused by abrasive action by sediment particles is observed. By increased transport capacity the size one of the major issues when designing the opera- and quantity of bouncing particles significantly in- tion of hydraulic structures. The issue is especially crease, and, simultaneously, the pulsations of pres- severe in spillways and outlets of dams on rivers sures in the water increase. This contributes to the with significant torrential character. intensity of abrasion. The damages on concrete surfaces that emerge are related to the increase of The term abrasion in hydraulic structures is the size of solid particles and intensity of impacts used for the process of disintegration of exposed against the bottom, where at first initial damages concrete surfaces, resulting from loads arising occur, which represent, with progressing processes, from sediment transport (Kryžanowski, 1991). The the core of progressive spreading of the damage in rate of disintegration of the concrete surface the direction of the water current (Jakobs et al. largely depends on the transport capacity of water 2001). and the ways of transport of solid matter (Mikoš 1993, Kim 2004). Accordingly, the abrasion of When designing concretes in hydraulic struc- concrete can be divided into several phases. In the tures it should be emphasised that there is no gen- initial phase, the process of abrasion is caused by eral criterion for defining abrasion resistance. Usu- sediment transport. The damage to concrete struc- ally, abrasion resistance of concretes is assessed tures thus results from polishing/milling due to based on a set of parameters that define the single rolling or sliding of sediments (solid particles) mechanical properties of concretes, such as: com- against the surface. By increased transport capac- pressive strength, tensile strength, aggregate ity, the small particles start to move in suspension, strength, use of special cements, modulus of elas- and large solid particles move by way of bouncing. ticity, water/cement (w/c) ratio, surface polishing,
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