Prediction of the Compressive Strength of Waste-Based Concretes Using Artificial Neural Network.

In the 21st century, numerous numerical calculation techniques have been discovered and used in several fields of science and technology. The purpose of this study was to use an artificial neural network (ANN) to forecast the compressive strength of waste-based concretes. The specimens studied include different kinds of mineral additions: metakaolin, silica fume, fly ash, limestone filler, marble waste, recycled aggregates, and ground granulated blast furnace slag. This method is based on the experimental results available for 1303 different mixtures gathered from 22 bibliographic sources for the ANN learning process. Based on a multilayer feedforward neural network model, the data were arranged and prepared to train and test the model. The model consists of 18 inputs following the type of cement, water content, water to binder ratio, replacement ratio, the quantity of superplasticizer, etc. The ANN model was built and applied with MATLAB software using the neural network module. According to the results forecast by the proposed neural network model, the ANN shows a strong capacity for predicting the compressive strength of concrete and is particularly precise with satisfactory accuracy (R² = 0.9888, MAPE = 2.87%).

Effects of organic matter on mechanical properties of dredged sediments for beneficial use in road construction.

In France, the road construction sector is the greatest consumer of granular materials, with a yearly consumption of about 200 million tons. With the shortage of standard materials, the valorisation of dredged sediments for road construction could constitute an interesting solution. Dredged sediments generally consist of a mineral phase, an organic phase (in various forms) and a liquid phase (water). The presence of organic matter (OM) in sediments, even in small amounts, affects their engineering properties. The main objective of this study is to investigate the effects of organic matter content on the engineering properties of dredged sediments. For this purpose, a specific methodology to reconstitute samples with different amounts of organic matter contents is proposed. The evaluation of the effects of organic matter content in term of compressibility, shear strength, compaction and bearing capacity show that even for high amount of organic matter the performances of the studied samples are compatible with the use in road construction sector.

Valorization of unauthorized sea disposal dredged sediments as a road foundation material.

The main objective of this study is to show the ability of fine dredged material (mainly silty material) to be used in road construction project. This paper is divided into three parts. In the first part, the physical, the mineralogical and the mechanical characteristics of the used fine dredged sediments, as well as their chemical composition and environmental impacts are presented. In the second part, the methodology developed to design the road made from dredged fine sediment is developed. The third part of the paper focuses on the presentation of the road construction and the interpretation of analyses made on cores drilled samples from the road and measurements of the deflection of the road. The environmental assessment, based on leaching tests, is also performed at different issues.

Experimental investigation on consistency limits of cement and lime-stabilized marine sediments.

This paper presents the effects of treatments with cement and lime on the consistency limits of marine sediments dredged from Dunkirk port. The Casagrande percussion test and the fall cone test were used to determine the liquid limits of raw sediments and treated marine sediments. For the evaluation of the plastic limits, the results of the fall cone test were compared with those obtained by the rolling test method. The relationship between the water contents and the penetration depths for the determination of the liquid limit and the plastic limit was explored. Liquid limits at 15.5 mm and plastic limits at 1.55 mm seem to be a more appropriate choice for the studied marine sediments compared with the limits determined by other used prediction methods. Finally, the effect of cement treatment and lime treatment on the Casagrande classification of the studied sediments was investigated according to the different prediction results.

Solidification/stabilization of dredged marine sediments for road construction.

Cement/lime-based solidification is an environmentally sound solution for the management of dredged marine sediments, instead of traditional solutions such as immersion. Based on the mineralogical composition and physical characteristics of Dunkirk sediments, the effects of cement and lime are assessed through Atterberg limits, modified Proctor compaction, unconfined compressive strength and indirect tensile strength tests. The variation of Atterberg limits and the improvement in strength are discussed at different binder contents. The potential of sediments solidified with cement or lime for road construction is evaluated through a proposed methodology from two aspects: I-CBR value and material classification. The test results show the feasibility of solidified dredged sediments for beneficial use as a material in road construction. Cement is superior to lime in terms of strength improvement, and adding 6% cement is an economic and reasonable method to stabilize fine sediments.

Monotonic aspects of the mechanical behaviour of bottom ash from municipal solid waste incineration and its potential use for road construction.

Municipal solid waste incineration (MSWI) bottom ash is an atypical granular material because it may include industrial by-products that result from the incineration of domestic waste. The prospects for the beneficial use of this particular material mainly lie in the field of road construction, as a substitute for the traditional natural aggregates. However, its mechanical properties are still little known, particularly in term of stiffness and deformability, characteristics that are essential to the construction of a durable roadway. The purpose of this paper is to describe better the mechanical behaviour of this recycled material. In order to reach this objective, a large experimental campaign is presented. The first part of this paper presents and comments in detail on the results obtained from static monotonic tests. Oedometric and triaxial shear tests were performed on MSWI bottom ash both before and after treatment with a specific hydraulic binder. These tests allow specification of the mechanical characteristics of the MSWI bottom ash, such as the initial Young's modulus, Poisson's ratio, the compressibility index, the friction angle, and the contracting or dilating behaviour of the material. The results reveal a mechanical behaviour similar to that of initially dense standard materials (sands, unbound granular materials) and a dependence on the applied average pressure, characteristic of the mechanical behaviour of granular media. More laboratory data on other samples of MSWI bottom ash are required to ensure that this comparison is statistically valid.

The use of marine sediments as a pavement base material.

The management of marine sediments after dredging has become increasingly complex. In the context of sustainable development, traditional solutions such as immersion will be increasingly regulated. More than ever, with the shortage of aggregates from quarries, dredged material could constitute a new source of materials. In this study of the potential of using dredged marine sediments in road construction, the first objective is to determine the physical and mechanical characteristics of fine sediments dredged from a harbour in the north of France. The impacts of these materials on the environment are also explored. In the second stage, the characteristics of the fine sediment are enhanced for use as a road material. At this stage, the treatment used is compatible with industrial constraints. To decrease the water content of the fine sediments, natural decantation is employed; in addition, dredged sand is added to enhance the granular distribution and to reinforce the granular skeleton. Finally, the characteristics of the mix are enhanced by incorporating binders (cement and/or lime). The mechanical characteristics measured on the mixes are compatible with their use as a base course material. Moreover, the obtained results demonstrate the effectiveness of lime in the mixes. In terms of environmental impacts, on the basis of leaching tests and according to available thresholds developed for the use of municipal solid waste incineration (MSWI) bottom ash in road construction, the designed dredged mixes satisfy the prescribed thresholds.