Sustainable Use of Reservoir Sediment through Partial Application in Building Material

Natalia Junakova,Jozef Junak

doi:10.3390/su9050852

Abstract

Sediment, often considered a by-product of various activities within river basin management to be disposed of, or a pollutant to be controlled, is increasingly being acknowledged as a resource in need of management. The paper deals with the possibility of reusing sediment from two Slovak reservoirs (Klusov and Ruzin) as an alternative raw material in concrete production. Concrete specimens were prepared by a combination of original reservoir sediment, reservoir sediment mechanically activated by dry milling, reservoir sediment mechanically activated by dry milling together with biomass incinerator fly-ash as a binder. To improve the strength properties of specimens, sodium hydroxide (NaOH) was used as a sediment activator. Mixtures containing 40% of binder replacement by the above-mentioned combinations of original and treated sediments were tested for flexural and compressive strengths after 28, 90 and 365 days of curing. The results showed that the mixtures prepared from sediments milled without and with addition of fly ash as cement replacement satisfied the strength requirements for the compressive strength class C16/20 according to the European standard except the composites prepared with NaOH as the sediment activator. Addition of NaOH into composites in the concentration of 5 M as an activator of sediment indicated the negative impact on compressive and flexural strengths and thus NaOH was not an effective pozzolanic activator for sediments. This study reveals that the sediment may be considered as 40% cement substitution in building materials.

Highlights

Declining of the storage capacity and the lifetime of water reservoirs, significantly reduced by the high rates of sedimentation, are at present important sediment-related problems
The average age of reservoirs is about 30 years and since many reservoirs have been designed with a dead storage for sedimentation of about 50 years, serious sedimentation problems are going to develop with about 40 percent of the storage capacity in reservoirs affected within the 20 years
The production of lightweight aggregates (LWA) made from dredged sediments has been evaluated in many studies [26,27,28,29,30] and the results have shown their suitability for lightweight aggregate production due to their perpetual availability, homogeneity and mineralogical and chemical composition [26]

Summary

Introduction

Declining of the storage capacity and the lifetime of water reservoirs, significantly reduced by the high rates of sedimentation, are at present important sediment-related problems. Many studies that have been undertaken to estimate the sediment load of the world’s rivers vary widely in terms of the assumptions made in the studies and reported effects of accelerated erosion due to human activities thereby reflecting the difficulty in obtaining reliable values for sediment concentration and discharge in many countries. Wohl [2] presented that human enterprises which cause soil erosion have increased the transport of sediment by the world’s rivers approximately 2.3 billion tons a year, but the storage in reservoirs has more than compensated for this increase, reducing sediment flux to the oceans by 1.4 billion tons a year. The study by White [4] showed that worldwide approximately 40,000 large reservoirs suffer from sedimentation and it was estimated that between 0.5% and 1% of the total storage capacity is lost annually. Several assessments demonstrated that the total amount of sediment dredged in Europe reaches 100–200 million cubic meters per year [7]

Objectives

Methods

Findings

Conclusion