Friction Characteristics Between Marine Clay and Construction Materials

Structure-soil interface friction characteristics is of importance to investigate the interaction between engineering structures and soils,especially for offshore structures.The interface friction behavior between marine clay and structural materials with different roughness was studied in this paper by using 3D optical scanning tests,a modified direct shear device and numerical simulation.Relationships between the surface roughness of structures,water content and interface friction angle were presented by model tests.The increase of water contents decreased the interface friction angles.For interfaces with different roughness,the interface friction angles will be smaller than that of the soil when the water content exceeds a certain value.The roughness of the interface and the water content of the soil are mutually coupled to influence the coefficient of friction(COF).This paper proposed a Finite Element Method(FEM)to simulate the interface direct shear tests of structures with different roughness.The surface models with different roughness are established based on the structure data obtained by 3D scanning.The Coupled Eulerian-Lagrangian(CEL)approach was employed to analyse soils sheared by irregular surfaces.The interface behavior for interfaces with different roughness under cyclic shear stresses was analyzed by FEM.

Outdoor Corrosion Performance Study of Selected Construction Materials in Bonny Island

Corrosion studies are important due to the enormous cost involved in the replacement of materials in all kinds of applications. The outdoor study on corrosion behavior of aluminum sheet, chequered aluminum plate and zinc alloys roofing sheet commonly used as construction material within a highly industrial settlement were examined using the gravimetric technique. The outdoor corrosion of these alloys at different sites was observed via its exposure to atmospheric conditions, monitored and recorded for 12 months at an interval of 2 months. Results depicted a process spanning the initial and intermediate stages of corrosion. The samples of construction materials at Bonny island showed substantial weight losses and rate of corrosion which varied largely on percentage of atmospheric humidity, salt precipitations, industrial aerosols and corrosive gases present at the exposure site as well as the nature of the material and the presence of protective coating formed during corrosion process. The rapid rate of deterioration of these materials causes severe economic importance on the indigenes’ activities including the oil and gas industries and other construction companies on the island. Thus, there is urgent need for research concerned with methods to control or prevent excessive deterioration of metals in Bonny Island.

Geotechnical,Mineralogical and Chemical Characterization of the Missole II Clayey Materials of Douala Sub-Basin(Cameroon)for Construction Materials

Geotechnical tests conducted on clayey materials of Missole II, Douala sub-basin of Cameroon showed that these materials present: fines particles (55 to 78 wt.%), sand (22 to 44 wt.%), and plasticity index of 13.8 to 21.6%. The X-ray diffraction (XRD) and the chemical analysis revealed a kaolinite amount of 46 to 56 wt.%, 19 to 27 wt.% of illite, 12 to 19 wt.% of quartz, 3 to 5 wt.% of goethite, 2 to 5 wt.% of hematite, 1.5 to 5 wt.% of anatase, 2 to 3 wt.% of feldspar-K with 52.87 to 63.11 wt.% of SiO2, 18.08 to 24.31 wt.% of Al2O3, 3.28 to 11.45 wt.% of Fe2O3 and a small content of bases (<2 wt.%). The results of geotechnical tests combined to those of the XRD and the chemical analysis showed that the Missole II clayey materials are suitable for the manufacture of bricks, tiles and sandstones.

Typology of Local Construction Materials from the Adamawa and North-West Regions of Cameroon

This article summarizes the different local construction materials observed in two regions of Cameroon (Adamawa and North-West). These raw materials were mapped and evaluated using various methods of investigation (spatial distribution, estimation of reserves, development of a database compatible with geo-referenced maps). The results obtained show three types of local construction materials (vegetal, pedological and geological) with quantitative estimation or distribution. Vegetal local materials include herbaceous savanna with strong dominance of straw in Adamawa region than the North West region. Pedological local construction materials include lateritic soils (ferruginous or clayey), harplan, sandy clay and sandy clay soil while geological local construction materials include volcanic, plutonic and metamorphic rocks. Many sites of these geological materials are suitable for the rock quarry plant. Adamawa region also contains sedimentary rocks constituted by metamorphic conglomerate and sandstones. Two main types of residential homes are constructed with these local construction materials in these regions of Cameroon. These include huts and houses.

Partial Replacement of Cement by Solid Wastes as New Materials for Green Sustainable Construction Applications

The manufacturing of ordinary Portland cement is an energy-intensive process that results in pollution and CO2 emissions,among other issues.There is a need for an environmentally friendly green concrete substitute.Waste products from a variety of sectors can be recycled and used as a green concrete substitute.This decreases the environmental effects of concrete manufacturing as well as energy consumption.The use of solid waste materials for green building is extremely important now and in the future.Green concrete is also in its infancy in terms of manufacturing and application.Academics must intervene by encouraging business implementation.The aim of this review paper is to raise awareness about the importance of repurposing recycled materials and to highlight new technologies for producing green,sustainable concrete.

Carbon Ramming Materials for Blast Furnace Construction

1 Scope This standard specifies the definition, classifica- tion, technical requirements, test methods, quality ap- praisal procedure, packing, marking, transportation, stroage and quality certificate of carbon ramming mate- rials for blast furnace construction. This standard is applicable to carbon ramming materials for construction in leveling layer of blast furnace bottom, ramming layer upper or lower the cen- tral line of water cooling pipes, joints between carbon bricks, or joints between carbon bricks and cooling equipment.

Estimating Construction Material Indices with ARIMA and Optimized NARNETs

Construction Industry operates relying on various key economic indicators.One of these indicators is material prices.On the other hand,cost is a key concern in all operations of the construction industry.In the uncertain conditions,reliable cost forecasts become an important source of information.Material cost is one of the key components of the overall cost of construction.In addition,cost overrun is a common problem in the construction industry,where nine out of ten construction projects face cost overrun.In order to carry out a successful cost management strategy and prevent cost overruns,it is very important to find reliable methods for the estimation of construction material prices.Material prices have a time dependent nature.In order to increase the foreseeability of the costs of construction materials,this study focuses on estimation of construction material indices through time series analysis.Two different types of analysis are implemented for estimation of the future values of construction material indices.The first method implemented was Autoregressive Integrated Moving Average(ARIMA),which is known to be successful in estimation of time series having a linear nature.The second method implementedwas Non-LinearAutoregressive Neural Network(NARNET)which is known to be successful in modeling and estimating of series with non-linear components.The results have shown that depending on the nature of the series,both these methods can successfully and accurately estimate the future values of the indices.In addition,we found out that Optimal NARNET architectures which provide better accuracy in estimation of the series can be identified/discovered as result of grid search on NARNET hyperparameters.

Numerical Simulation and Experimental Characterization of Clay Paste under Loads for Energy Saving in Clay Materials Processing

Requirements for the respect of the environment encourage to reduce the impact of human activity on the nature. Civil engineering answers these requirements by the development of ecological construction materials. This paper deals with the transformation of clay raw materials which enable the processing of environmentally friendly construction materials: in addition to their biodegradability, the alveolar fired clay materials allow energy saving in home heating thanks to their thermal isolation properties. But their manufacturing is a high energy consumption process, in particular during compaction, drying and firing which contribute to the emission of greenhouse gases. The goal of this paper is to study the rheology of clay pastes in order to develop low energy in manufacturing processes. For this purpose, theoretical and experimental approaches were carried out on six clay varieties. In the theoretical approach, a finite element (FE) simulation model has been developed for pressing a non-rigid material predicting deformations and stresses occurring within the clay structure. Experiments have then been carried out to validate the finite element modelling. In this experimental approach, the clay pastes were transformed with water content respecting the Atterberg limits which determine the plasticity of clays. The samples compaction has been carried out under variable loadings in order to determine the suitable low energy consumption loading.

Life Cycle Assessment:Embedded and Maintenance Environmental Impacts of Social Interest Housing Construction Systems

Characterized by high consumption of natural resources and great generation of environmental impacts,civil construction becomes an important ally to the development of strategies for a more sustainable built environment.In this context,this article aims to evaluate construction systems of social interest housing and point out their participation in relation to total impacts,in addition to indicating the environmental impacts embedded in the construction materials present in these systems.To this end,a case study was selected to apply Life Cycle Assessment(LCA)methodology and assess impacts of the building materials used in a house of a social housing complex.LCA was applied to masonry,roof,coatings and floor systems.The scope adopted assesses impacts incorporated in construction materials,analyzing the stages of raw material extraction,materials production,transport to construction site,maintenance and materials replacement.Concerning life cycle inventory,Ecoinvent 3.6 database was used and environmental impacts were calculated using CML method with the aid of OpenLCA 1.9 software.In general,results showed that the maintenance phase has the greatest environmental impact participation related to analyzed systems.Furthermore,it was possible to conclude that coatings and masonry systems were the ones that most added to total environmental impacts.

Developing Sustainable High Strength Concrete Mixtures Using Local Materials and Recycled Concrete

This study presents the development of high strength concrete (HSC) that has been made more sustainable by using both local materials from central Texas and recycled concrete aggregate (RCA), which has also been obtained locally. The developed mixtures were proportioned with local constituents to increase the sustainable impact of the material by reducing emissions due to shipping as well as to make HSC more affordable to a wider variety of applications. The specific constituents were: limestone, dolomite, manufactured sand (limestone), locally available Type I/II cement, silica fume, and recycled concrete aggregate, which was obtained from a local recycler which obtains their product from local demolition. Multiple variables were investigated, such as the aggregate type and size, concrete age (7, 14, and 28-days), the curing regimen, and the water-to-cement ratio (w/c) to optimize a HSC mixture that used local materials. This systematic development revealed that heat curing the specimens in a water bath at 50℃ (122oF) after demolding and then dry curing at 200℃ (392oF) two days before testing with a w/c of 0.28 at 28-days produced the highest compressive strengths. Once an optimum HSC mixture was identified a partial replacement of the coarse aggregate with RCA was completed at 10%, 20%, and 30%. The results showed a loss in compressive strength with an increase in RCA replacement percentages, with the highest strength being approximately 93.0 MPa (13,484 psi) at 28-days for the 10% RCA replacement. The lowest strength obtained from an RCA-HSC mixture was approximately 72.9 (MPa) (10,576 psi) at 7-days. The compressive strengths obtained from the HSC mixtures containing RCA developed in this study are comparable to HSC strengths presented in the literature. Developing this innovative material with local materials and RCA ultimately produces a novel sustainable construction material, reduces the costs, and produces mechanical performance similar to prepackaged, commercially, available construction building materials.

Review on The Teaching of Building Materials in Higher Vocational Colleges Based on the“Three Educations”Reformation

Building materials is not only a basic course content of architectural specialization,but also a practical course content taught in higher vocational institutions.It has a large number of knowledge points,a large number of principled and operational contents,and weak logic,all of which have an impact on the teaching effect.It is necessary to strengthen research on higher vocational building materials curriculum against the background of“three educations”reformation,as well as explore curriculum teaching reform strategy in conjunction with the current situation of higher vocational building materials curriculum teaching,in order to cultivate talents of high quality and professional ability.

Mixed Stone-timber Masonry in Traditional Construction: Structural, Architectural and Anti-seismic Features across Europe

This paper investigates the stone masonry with timber reinforcement through the European traditional and historical architecture.It is a remarkable practice consisting of combining different materials to build up a masonry.This technology shows a wide variety of typological,formal,and technological types of buildings across Europe as it is strongly influenced by the nature and availability of local materials,the cultural aspects of the various communities,and the soils geological nature.As a consequence,the same constructive typology is based on different premises and leads to many interesting results.In this paper the various uses of such a mixed stone-timber masonry are shown in relation to the above mentioned factors.One of the most interesting aspect is the use of such a mix stone-timber as an anti-seismic device,especially in the Southern and Mediterranean countries,giving evidence to a great sensibility of the ancient builders to very specific topics.It is also important to stress that this traditional technology is also highly contemporary being exploited in many countries,especially in the far northern ones.Furthermore,novel regulations have been issued in order to regulate such a discipline,especially the use of timber for large structure and infrastructure.Finally,as a very common constructive technology,many historical buildings present such a mixed structural configuration,independently from the generating factors.In such a perspective,this study aims to describe the most common constructive features,as well as develop guidelines for preservation,whereas the typology is present,or design criteria for consolidation and structural improvement,whereas necessary.

River Sand Characterization for Its Use in Concrete: A Revue

Despite the gradual professionalization of the construction sector as well as the abundance of sand mining sites offered by the North Kivu, Democratic Republic of Congo Region, ignorance of materials by local builders persists. This is the case of quarries extracting river sand used to make concrete and mortar. However, the dosages of the various constituents are most often chosen on the basis of experience without any prior characterization of this material. This paper presents a comprehensive review of the characterization of river sand for its use in concrete in DRC. The origin and global use of river sand in construction are presented in percentage terms to highlight the importance of river sand as a construction material. The physical properties of river sand, including particle size distribution, bulk density, absolute density, and cleanliness are discussed in detail. The paper examines the effect of variations in river sand properties on concrete behavior, including density and compressive strength. Overall, this paper emphasizes the need to properly characterize river sand before using it in construction to ensure durable, high-quality structures. This will avoid the problems that are observed in particular a bad behavior of the coating on the walls;cracks and crumbling of the beams, lintels, posts and even the ruin of the structures.

Effect of Surfactant Stabilizers on the Distribution of Carbon Nanotubes in Aqueous Media

The results of a study on the homogeneity of suspensions are described considering the effect of different types of surfactant stabilizers and their concentrations on the uniform distribution of a carbon nanotubes（CNTs）-based modifying additive to construction materials in an aqueous medium. This problem was solved herein by using surfactants and ultrasound. The sonication treatment of CNTs particle agglomerates allowed for dispersing their globules and achieving a 15-20-fold decrease in their average size, for which it became possible to make better use of the CNTs as cement modifier. As a result of the experimental studies carried out, the effect of the surfactant type and concentration promoting uniform distribution of the CNTs in the bulk of the suspension and, correspondingly, in the structural composite matrix was revealed. The CNTs-based additive improved the physical-mechanical and operational characteristics of the material.

Mechanical Characterisation of Densified Hardwood with Regard to Structural Applications

The demand for high-performance,yet eco-friendly materials is increasing on all scales from small applications in the car industry,instrument or furniture manufacturing to greater dimensions like floorings,balcony furnishings and even construction.Wood offers a good choice on all of these scales and can be modified and improved in many different ways.In this study,two common European hardwood species,Beech(Fagus sylvatica L.)and Ash(Fraxinus excelsior L.)were densified in radial direction by thermo-mechanical treatment and the densified product was investigated in an extensive characterisation series to determine all relevant mechanical properties.Compression in the three main directions(longitudinal,tangential,radial)and tension perpendicular to the grain(tangential,radial)were tested and compared to reference specimens with native density.Strength and modulus of elasticity were determined in all tests.In addition,a Life Cycle Assessment was carried out to evaluate the environmental impact associated to the densification process.The experimental investigations showed that strength and stiffness of hardwood in the longitudinal and tangential directions improve significantly by radial densification,whereas some properties in the radial direction decrease.The Life Cycle Assessment showed that artificial wood drying has higher impact than wood densification.Furthermore,the transport distance of the raw material highly influences the environmental impact of the final densified product.The paper then also offers an overview of possible applications in structural timber construction.Densified hardwood is a viable option as local reinforcement,where high compressive or tensile strength is needed.The wood densification process offers an alternative to the use of carbon-intense steel components or hardwoods from tropical forests.

Identification of Glass Powders and Sands from the Crushing of Glass Waste from the City of Loméin Togo

The sustainability of a city depends on the effective and efficient management of its solid waste. Waste recycling channels mainly process glass bottles for direct reuse. Some of these sectors carry out the crushing and grinding of end-of-life glass waste for use in civil engineering without the identification in terms of building materials being clearly established. The present study therefore aims to determine the physical and chemical characteristics of glass powders and sands resulting from the crushing and grinding of glass waste from Grand Lomé in Togo in order to consider their granular potential. Samples of sand and glass powder from the crushing and grinding of white, brown and green glass were subjected to characterization tests in the laboratory followed by analysis of the granular parameters and their modeling by Weibull’s law. The results show that the powder and the glass sand contain a high proportion of silica (SiO2) ranging from 69.11% to 70.18% and a low proportion of alumina (Al2O3) (less than 0.07) and iron (Fe2O3) (lower to 1.09). These three materials have tight and male graded grain sizes (Cu Cc omogeneous (k < 2.89). The absolute density (2 dab < 3) and the fineness modulus (Mf 2.1) make these materials probable aggregates for plaster and coating mortars. Nevertheless, an in-depth study will be made to determine a suitable formula.

Engineering and microstructure properties of contaminated marine sediments solidified by high content of incinerated sewage sludge ash

Management of incinerated sewage sludge ash(ISSA)and dredged contaminated marine sediments(CMSs)is a great challenge for Hong Kong and other coastal cities due to limited landfilling capacity.The present study investigates the use of high content(20%of sediment by mass)of ISSA in combination with cement/lime for solidification/stabilization(S/S)treatment of CMSs to provide a way to reuse the wastes as construction materials.The results showed that ISSA being a porous material was able to absorb a large amount of water rendering a more efficient solidification process of the marine sediment which normally had a very high water content(w80%).The S/S treatment improved the engineering properties of the sediment,but reduced the workability,especially for the lime-treated samples.Lime can be used to replace ordinary Portland cement(OPC)for better heavy metal immobilization and carbon emission reduction.The hardened sediment samples prepared with 10%of lime and 20%of ISSA could attain a strength of 1.6 MPa after 28 d of curing.In addition,leaching tests confirmed that there was no environmental risk induced by these stabilized materials.The formation of hydrated cementitious compounds including calcium silicate hydrate(CeSeH)/calcium aluminate silicate hydrate(C-A-S-H)/hydrocalumite/calcite was mainly responsible for the strength development in the ISSA/lime-treated sediments.

Feasibility Study of Applying Recycled Aggregate from Building Debris in Concrete

Coarse and fine aggregate constitutes an average of approximately 55% to 80% of the total volume of concrete materials.Concrete remains the most commonly-used building material worldwide.As a result,the massive use of aggregate will have a direct impact on the earth′s natural resources if an appropriate replacement material is not found,violating the spirit of sustainable development.This study makes a preliminary examination of using coarse and fine aggregate produced from discarded construction materials in concrete.Results indicate that the compressive strength of densified mixture concrete at 28 days can reach 56.88 MPa(recycled materials used as coarse aggregate,and natural sand used as fine aggregate)and 53.33 MPa(recycled materials used as both coarse and fine aggregate).While this type of material is not yet fully understood,further research into this area should enable feasible applications in concrete.However,unsuitable mixtures have serious impact on the durability and overall economy of concrete.Pending further research on suitable mixture designs,a complete application of recycled aggregate in concrete can be expected.

State of the art review on physiochemical and engineering characteristics of fly ash and its applications

The focus of this study is to critically review the physiochemical and engineering properties of the fly ash and its applications in various fields.The utilization of fly ash has become a widespread area,but the amount of utilization is still a serious issue.It has many beneficial qualities(such as pozzolanic property,fineness,spherical shape,lightweight,etc.),which enhance its properties and make it suitable for its utilization as a new construction material.For the bulk utilization of fly ash,it should be employed in the areas independent of any other parameters.So that,the disposal problem can be reduced significantly.The knowledge of its physiochemical characteristic helps in the judgment of appropriate fly ash for any particular type of work.Fly ash can be utilized in other areas such as asphalt concrete,geopolymer concrete,ground improvement,agricultural sector,roller compacted concrete,brick,etc.that will reduce the existing ashes,and also the disposal problem can be solved appreciably.The implementation of fly ash must be avoided below the natural ground water level and below 4°C temperature conditions.