Implementation on a Preparation and Controlled Compaction Procedure for Waste-Fiber-Reinforced Raw Earth Samples

Earth bricks are a traditional eco-friendly construction material. In this study, harbor-dredged sediments were used along with hemp shiv to develop a brick manufacturing procedure and compaction techniques to produce durable earth bricks for the valorization of waste hemp shiv and dredged sediments. Prismatic specimens of size 4 × 4 × 16 cm3 were manufactured with Dunkirk sediments after analyzing their suitability for earth bricks according to the French standard for flexural strength test to observe the indirect tensile strength and impact of the compaction techniques on the strength of bricks. Crude bricks were manufactured with varying hemp shiv content from 0% to 5% by mass. Compaction techniques such as dynamic compaction, static compaction, and tamping were applied. The effect of hemp shiv content and compaction techniques was evaluated with a flexural strength test and the distribution of fibers in bricks. Grain size analysis of sediments with French and Spanish standards shows that the sediments granulometry is suitable for earth bricks. The flexural strength testing of bricks indicates that bricks with saturated hemp shiv have higher flexural strength. Earth bricks have maximum strength with dynamic compaction with 1% hemp shiv, which satisfies the adobe bricks tensile strength requirements that vary from 0.012 to 0.025 MPa (NZS 4298, 1998; NORMA E.080 (2017).

Dredged Dam Raw Sediments Geotechnical Characterization for Beneficial Use in Road Construction

The present research work aims to evaluate the feasibility of reusing raw dredged sediments from the Dam of Fergoug (northwestern Algeria) as an alternative material for road construction. These sediments were added to volcanic tuff from the quarry located near the village of Sidi Ali Cherif, in the town of Sig (northwestern Algeria), with contents of 5, 10, 15, 20 and 25% by total weight of tuff. To achieve this goal, sediments were extracted from Fergoug dam and an experimental program was carried out to study the possibility of valorizing these sediments to be used in road construction. The soils were subjected to a series of physical and chemical tests. Their physical properties, including the Atterberg limits, specific gravity, grain size distribution, and organic content were determined according to standard methods. Then, their chemical properties, including pH, elementary chemical composition using the X-ray fluorescence spectrometry and mineralogical composition identified by X-ray diffraction, were obtained by means of standard methods. The first experimental results from the tested formulations demonstrated the feasibility of reusing the valorized dredged sediments in road construction. Afterwards, the modified Proctor and ICBR tests were carried out, and the results obtained turned out to be quite satisfactory.

Ascomycetes versus Spent Mushroom Substrate in Mycoremediation of Dredged Sediments Contaminated by Total Petroleum Hydrocarbons: The Involvement of the Bacterial Metabolism

Two mycoremediation approaches for the depletion of the total petroleum hydrocarbons in dredged sediments were compared: co-composting with spent mushroom substrate (SMS) from Pleurotus ostreatus and bioaugmentation with Lambertella sp. MUT 5852, an ascomycetes autochthonous to the sediment, capable of utilizing diesel oil its sole carbon source. After 28 days of incubation, 99% depletion was observed in presence of Lambertella sp. MUT 5852. No total petroleum hydrocarbon depletion was observed in sediment co-composting with the SMS after 60 days of incubation. 16S rDNA metabarcoding of the bacterial community was performed to evaluate the potential synergism between fungi and bacteria in the bioremediation process. The functional metagenomic prediction approach indicated that the biodiversity of the bacterial genera potentially involved in the degradation of TPH was higher in sediment bioaugmented with Lambertella sp. MUT 5852, which resulted in being mandatory for TPH depletion. Mechanisms of co-substrate inhibition of the hydrocarburoclastic bacterial species, due to the bioavailable organic matter of the SMS, are suggested to be involved in the observed kinetics of TPH depletion, failing in the case of SMS and successful in the case of Lambertella sp. MUT 5852.

Influence of drying methods on physicals, mineralogical and environmental characteristics of a marine sediment.

Dredged sediments are considered as waste according to European regulations. Hence, management of such waste could be of increasingly concerns given the growing ecological consciousness of the population. One solution to enhance the management of this waste is to promote the valorization of dredged sediments in civil engineering works. Prior to valorization, better acknowledgement of sediments characteristics is of capital importance.The materials used in civil engineering works classified into different categories by different systems of classification. The systems used in road construction sector is based on different parameters such as particles size distribution, Methylene bleu Value, Atterberg limits and organic matter content. Additional test could be necessary in order to enhance the knowledge about the chemical and mineralogical characteristics of the materials.For investigating the sediment characteristics in the laboratory, dry sediments materials should be prepared in some tests, such as organic matter content determination, XRD and XRF analyses, specific surface area, specific density and other tests. In the literature, several methods exist to perform this drying. However, the effects on parameters measurement not fully known.In this paper, a comparative study of three drying methods is undertaken to assess the effects on few physical and chemical parameter measurements toughed important for material valorization in road construction. These methods composed by oven-drying, freeze-drying, and natural drying. When drying is not necessary, the effects on the results of these preparation methods compared to the results from undried material. It shown, that for all the investigated tests, the drying methods affects the obtained results. The relative differences could be very important regarding the results obtained on undried samples. However, these differences have to be mitigated regarding the field of the study.Statement of NoveltyThis research shows the importance of sediments' drying methods in their valorization process which are not commonly assessed.A comparative study of three drying methods is undertaken to understand the drying effects on sediments' properties, by evaluating the effects on certain physical and chemical parameters, which are critical for upgrading these materials in road construction.This study had clearly shown that the drying method has different effects on physical and chemical characteristics.