Showing papers in "European Journal of Environmental and Civil Engineering in 2017"
TL;DR: In this article, a micromorphic, non-linear 3D model aiming to describe internal friction phenomena in concrete is considered, where a reduced two-degrees-of-freedom model is employed for the sake of easy handling to explain dissipative loops which have been observed in some concrete specimens tested under cyclic uniaxial compression loading with different frequencies and having various amplitudes but never inducing large strains.
Abstract: In this paper, a micromorphic, non-linear 3D model aiming to describe internal friction phenomena in concrete is considered. A reduced two-degrees-of-freedom model is employed for the sake of easy handling to explain dissipative loops which have been observed in some concrete specimens tested under cyclic uniaxial compression loading with different frequencies and having various amplitudes but never inducing large strains. As (linear or non-linear) viscoelastic models do not seem suitable to describe neither qualitatively nor quantitatively the measured dissipation loops, we propose to introduce a multi-scale micromechanism of Coulomb-type internal dissipation associated to the relative motion of the faces of the microcracks present in the material and to the asperities inside the microcracks. We finally present numerical simulations showing that the proposed model is suitable to describe some of the available experimental evidence.
85 citations
TL;DR: In this paper, the authors applied the Bayes' rule for comprehensive assessment of the water quality of the Brahmani River and the likelihood estimates are obtained from the normal distribution and is pre-owned for posterior probability calculation through Bayes's rule.
Abstract: The quality of water of the river has a significant impact on human population and livestock in basin area. Six water quality indicators are monitored from the gauging stations of Brahmani River to assess the changing trends in the quality of water. The conventional Aggregative Index Evaluation method is applied to know the overall water quality index for its intended use. Further, in this study, Bayes’ rule is applied for comprehensive assessment. The likelihood estimates are obtained from the normal distribution and is pre-owned for posterior probability calculation through Bayes’ rule. Finally, the indicator weights are estimated by Shannon’s entropy weight method. The consequences of analysis specified that the indicator, CODMn, is affecting the quality of water more in Panposh downstream. Biological oxygen demand, TA as CaCO3, NH4–N and Nitrate-N are closely related to domestic pollution and agricultural non-point source pollution. The overall quality of water is improved during dry seasons than duri...
82 citations
TL;DR: In this paper, the role of force chains in granular materials under both quasi-static biaxial loading and dynamic impact loading conditions was investigated, and it was shown that force chains are responsible for the strength of the sample.
Abstract: This paper investigates the role of force chains in granular materials under both quasi-static biaxial loading and dynamic impact loading conditions. This study is mainly interested in investigating the role of force chains on the global mechanical responses of samples as well as on the microstructure of granular materials. For this purpose, discrete element methods are adopted to perform different loading tests. Granular materials are modelled as aggregations of poly-disperse spherical particles. Results first show that force chains are responsible for the strength of the sample: in 2D biaxial test, the establishment and buckling of force chains are responsible for the evolution in terms of deviatoric stress; in 3D dynamic impact test, the development and the buckling of force chains are responsible for the evolution of impact force on the impacting projectile. Second, force chains are found to play an important role in the microstructure of granular materials: in statics, the buckling of force chains ma...
73 citations
TL;DR: In this paper, an integrated approach targeting sustainability, safety and resilience is envisioned for the renovation of the post-Second World War RC buildings clustered in urban outskirts in order to support sustainable, safety, and resilience.
Abstract: In this paper, an integrated approach targeting sustainability, safety and resilience is envisioned for the renovation of the post-Second World War RC buildings clustered in urban outskirts. The so...
64 citations
TL;DR: A review of the state of the art on the computational strategies developed for the analysis of inverse problems can be found in this article, where the main problems to overcome and the attainable accuracy are discussed.
Abstract: In this work, the author gives a review of the state of the art on the computational strategies developed for the analysis of inverse problems. Starting from the definition of the inverse problem, and focusing the intrinsic difficulties in their solution, various computational tools developed for their solution are presented and discussed. This allows an aware choice of the most effective strategies with respect to the problem to be dealt with. Successively, some selected inverse problems are briefly sketched and their numerical solution is thoroughly discussed. This allows to enlighten the main problems to overcome and the attainable accuracy. Finally, new and challenging inverse problems are addressed, discussing thoroughly some current and classical results, in order to outline future perspectives.
54 citations
TL;DR: In this paper, a cost analysis of one-part alkali-activated cements with enhanced thermal conductivity is presented, which includes global warming potential assessment and cost analysis, and two carbon dioxide social costs scenarios are also included.
Abstract: Increasing building energy efficiency is one the most cost-effective ways to reduce emissions. The use of thermal insulation materials mitigates heat loss in buildings, therefore minimising heat energy needs. In recent years, several papers were published on the subject of foam alkali-activated cements with enhanced thermal conductivity. However, on those papers cost analysis was strangely avoided. This paper presents experimental results on one-part alkali-activated cements. It also includes global warming potential assessment and cost analysis. Foam one-part alkali-activated cements cost simulations considering two carbon dioxide social costs scenarios are also included. The results show that one-part alkali-activated cements mixtures based on 26%OPC + 58.3%FA + 8%CS + 7.7%CH and 3.5% hydrogen peroxide constitute a promising cost-efficient (67 euro/m3), thermal insulation solution for floor heating systems. This mixture presents a low global warming potential of 443 KgCO2eq/m3. The results confirm that ...
52 citations
TL;DR: In this paper, the authors examined the engineering properties of lightweight aggregate concretes (LWACs) incorporating a novel Expanded Polystyrene (EPS)-based lightweight aggregated called Stabilised PolyStyrene (SPS), which was produced by 80% waste EPS, 10% clay and 10% cement.
Abstract: This study examines the engineering properties of lightweight aggregate concretes (LWACs) incorporating a novel Expanded Polystyrene (EPS)-based lightweight aggregated called Stabilised Polystyrene (SPS). The SPS aggregate was produced by 80% waste EPS, 10% clay and 10% cement. The influence of the increasing incorporation of SPS on the workability, density, compressive strength, flexural strength, ultrasonic pulse velocity, drying shrinkage, expansion and water absorption (WA) of the different concretes has been investigated. The results showed that the use of SPS enabled to reduce the density of concrete by 8–52% compared to that of the control concrete. The reduction in density was due to the increase in total porosity in the lightweight concretes (LWCs), which also induced higher WA, drying shrinkage and expansion. The 28-day compressive strength of the LWAC was in the range of 4.6–16.4 MPa; thus, the concrete mixture with the higher performances almost satisfied the mechanical and density criteria of...
49 citations
TL;DR: In this paper, a granular soil REV located on the upstream side of the erosion pipe front is modelled numerically, at the grain scale, by coupling the Discrete Element Method (DEM) with the Lattice Boltzmann Method (LBM) for the representation of the solid and fluid phases, respectively.
Abstract: A granular soil REV located on the upstream side of the erosion pipe front is modelled numerically, at the grain scale, by coupling the Discrete Element Method (DEM) with the Lattice Boltzmann Method (LBM) for the representation of the solid and fluid phases, respectively. The implementation of DEM follows a standard molecular dynamics approach and the interactions between grains are regulated by unilateral contacts and breakable bonds. A synopsis of the LBM scheme is provided, with focus on the implementation of non-slip conditions for moving boundaries and use of the Multiple Relaxation Time approach for improved numerical stability. The coupling scheme is described along with the criteria for setting the numerical parameters of the two methods. After a “dry” preparation procedure, the numerical REV is tested under fully saturated conditions and increasing pressure difference. Backward erosion is observed and a micromechanical inspection of the granular phase suggests that arching through force ...
41 citations
TL;DR: In this paper, the authors present the results of an experimental investigation on incorporating small dosages of NMMT clays (25,.50,.75 and 1.00% addition by mass of total cementitious material) into SCCs.
Abstract: The properties of self-compacting concrete (SCC) can be manipulated by the addition of nano-montmorillonite (NMMT) clays. This paper presents the results of an experimental investigation on incorporating small dosages of NMMT clays (.25, .50, .75 and 1.00% addition by mass of total cementitious material) into SCC. Tests were conducted on fresh and hardened specimens to measure workability (by slump flow, V-funnel and L-box), mechanical (by compressive and splitting tensile strengths), durability (electrical resistivity and water penetration) and microstructural (X-ray diffraction and scanning electron microscopy) properties of control and NMMT-reinforced SCCs. The results showed that the addition of .5% NMMT resulted in the highest compressive strength; however, a mixture with .75% NMMT had the highest splitting tensile strength among mixtures at curing ages of 7, 28 and 56 days. Nevertheless, durability of specimens was improved by the addition of NMMT up to 1%. X-ray diffraction (XRD) and scanning electr...
40 citations
TL;DR: In this paper, a new meso-scale model of cementitious materials is proposed, based on a random method that allocates at each Gauss point of the finite element discretisation of the Representative Volume Element a specific phase of the mixture: aggregate, mortar and void.
Abstract: Concrete is a heterogeneous structural material whose constitutive behaviour is strictly depending on the mechanical properties of the aggregates and the mortar. Its behaviour is often macroscopically characterised by assigning homogenised mechanical properties. A number of methods are devoted to the prediction of the mechanical properties of the composite material by means of meso-scale analysis. The paper concerns a new meso-scale model of cementitious materials. The numerical description of the meso-scale structure is attained using a random method that allocates at each Gauss point of the finite element discretisation of the Representative Volume Element a specific phase of the mixture: aggregate, mortar and void. Each phase is characterised by a specific constitutive model. The method is tested with numerical simulations of cyclic uniaxial compression tests and of multiaxial compression tests, the latter leading to the generation of a biaxial strength domain, for different values of the confinement p...
35 citations
TL;DR: In this article, the authors studied the influence of the masonry infill panels and the seismic safety of the building on the soft storey mechanism when subjected to seismic actions, and different strengthening techniques were tested to fix/eliminate the soft-storey response.
Abstract: The assessment of seismic vulnerability and strengthening of existing buildings is a topic of relevant importance and priority, as evidenced in recent earthquakes around the world, particularly in Southern European countries. Some architectural solutions adopted in the decade of 1970, combined with the common design and construction practices at that time, particularly in what regards to the seismic design, influences the seismic vulnerability of these structures. The objective of the present work is to study, based on numerical analyses, different strengthening techniques to adopt into an existing building with the behaviour potentially governed by soft storey mechanism when subjected to seismic actions. The influence of the masonry infill panels will be studied and the seismic safety of the building will be assessed. Also, different strengthening techniques will be tested to fix/eliminate the soft storey like response, namely: RC columns jacketing, addition of steel bracings with and without shear link ...
TL;DR: In this article, the authors discuss the effect of ultrafine materials on the overall cost of self-compact concrete and its hydration heat and potential effects on properties such as shrinkage and cracking.
Abstract: Self-compacting concrete’s (SCC’s) particular need for self-compacting, i.e. to achieve a high passing and filling ability, deformability capacities and a high resistance to segregation, necessarily requires the reduction of the volume of coarse aggregate and the increase of the volume of ultrafine materials and admixtures (mainly superplasticisers). The increase in the volume of ultrafine materials mentioned, achieved exclusively at the cost of the cement, would have, as main effects, the significant increase of the overall cost of SCC, of its hydration heat and potential effects on properties such as shrinkage and cracking. Consequently, significant amounts of mineral additions are usually incorporated, in replacement of part of the cement to improve the workability properties, reduce the production of hydration heat and reduce the overall cost. Mainly because it needs to incorporate significant quantities of ultrafine materials (cement and mineral additions), SCC has great potential for the use of thes...
TL;DR: In this paper, the authors investigated the influence of substitution of limestone powder (LSP) by silica sand (SS) on properties of engineered cementitious composites (ECC).
Abstract: This paper presents the results of an investigation on the influence of a replacement of limestone powder (LSP) by silica sand (SS) on properties of engineered cementitious composites (ECC). For this purpose, five different ECC mixtures were adopted: ECC mixture with only SS (M1) for control purposes and four ECC mixtures in which SS is partially replaced by four levels of replacements (25, 50, 75 and 100% by weight of total SS) of LSP. The mechanical properties of ECC were investigated for 3, 28 and 90 days, while the durability tests were performed for 90 days. It was concluded that increase in LSP content resulted in a decrease in fluidity of ECC mixtures indicating longer flow times. Increase in the LSP content had a positive effect on the performance of the compressive strength, fracture toughness and flexural strength at the ages of 3 and 28 days, while this was not valid at the age of 90 days when compared to the reference mixture M1. Moreover, it can be said that the use of LSP instead of SS in EC...
TL;DR: In this paper, numerical cracking localisation, mesh discretisation, steel bar and concrete interactions and/or contact law between the hammer and concrete are used to predict how an impact load will affect a reinforced concrete slab, some of which may be impractical or expensive.
Abstract: Reinforced concrete slabs are the common structural elements in almost all reinforced concrete structures. An accidental impact load in such an element can be caused by mishaps in industry as well as accidents provided from transportation and artificial disasters or natural hazard as rock fall. The behaviour of reinforced concrete slabs under impact loads is not always respected or correctly taken into account. There are a number of ways to predict how an impact load will affect a reinforced concrete slab, some of which may be impractical or expensive, but because there have been significant developments in technology, numerical techniques rather than experimental approaches have become popular methods for developing detailed responses. The intent of this study is not to give an original development to any of the specific aspects (e.g. numerical cracking localisation, mesh discretisation, steel bar and concrete interactions and/or contact law between the hammer and concrete) involved in the problem. The i...
TL;DR: In this paper, a time-fractional derivative diffusion model for the description of the time-dependent chloride ions penetration in reinforced concrete structures exposed to chloride environments is developed. But the model is not suitable for the case of concrete structures.
Abstract: This article develops a time-fractional derivative diffusion model for the description of the time-dependent chloride ions penetration in reinforced concrete structures exposed to chloride environments. A comparative investigation of time-fractional diffusion model and power law time-dependent coefficient model is studied to demonstrate the validity of this present model. The parameters in the proposed model can be statistically determined by analysing the mean square displacement of experimental data or data fitting techniques, and the model can be used to predict the chloride profiles with time-dependent property. It is also noted that the fractional derivative order in the proposed model characterises the rate of chloride penetration in concrete.
TL;DR: In this paper, an intelligent surrogate model based on extreme learning machine is proposed for slope system reliability analysis, which optimizes the weights and bias which play an important role in the performance of ELM are optimised by a nature inspired artificial bee colony algorithm.
Abstract: Geotechnical engineering problems are characterised by many sources of uncertainty, and reliability analysis is needed to take the uncertainties into account. An intelligent surrogate model based on extreme learning machine is proposed for slope system reliability analysis. The weights and bias which play an important role in the performance of ELM are optimised by a nature inspired artificial bee colony algorithm. The system failure probability of soil slopes is estimated by Monte Carlo simulation via the proposed surrogate model. Experimental results show that the proposed method is feasible, effective and simple to implement system reliability analysis of soil slopes.
TL;DR: In this paper, the effect of changes in the soil suction on volume changes, expansion index, swelling pressure, shear strength and the coefficient of permeability was investigated on pure bentonite and bentonite mixed with sand with proportions of 30, 40 and 50% at different initial water contents and dry unit weights.
Abstract: To investigate the effect of the changes in the soil suction on volume changes, expansion index, swelling pressure, shear strength and the coefficient of permeability, small-scale experiments were conducted on pure bentonite and bentonite mixed with sand with proportions of 30, 40 and 50% at different initial water contents and dry unit weights that were chosen from the compaction curves. In addition, large-scale model of soil with dimensions (700 × 700 × 650) mm was used to prepare the soil samples at the same initial water content and dry unit weight to show the effect of water content changes in different relations (swelling with time, swelling pressure with time, shear strength and soil suction). The results showed that the swelling potential decreases with increase in sand content from 14 to 2.4% by adding 50% sand to pure bentonite. The swelling percent found from the large-scale model is higher than that obtained from the oedometer swelling test for the same soil. This result applies well o...
TL;DR: In this article, the effect of added lime on the physical properties of soil has been investigated on a local natural clayey soil in order to investigate the influence of lime on consistency limits, total specific surface, compaction characteristics, swelling potential and swelling pressure.
Abstract: Over the last three decades, highly plastic soils have been one of the major sources of problems in roads, railways and buildings in Algeria. In these cases, soil treatment is essential to improve the engineering properties of these materials. The aim of this article was to study the effect of added lime on the physical properties of soil. Experiments were performed on a local natural clayey soil in order to investigate the influence of lime on consistency limits, total specific surface, compaction characteristics, swelling potential and swelling pressure. In addition, mercury intrusion porosimetry tests were carried out to determine the pore size distribution of the untreated and treated samples. The results show that the liquid limit decreases, the plastic limit increases and the total specific surface area decreases with the percentage of added lime. Compaction characteristics are affected by the addition of lime, the optimum water content increasing and the maximum dry unit weight decreasing in the pr...
TL;DR: In this paper, a steel slag-based composite material (SSC) was proposed to replace the traditional cement for the stabilisation of soft clays in deep mixing of deep mixing.
Abstract: A new steel slag-based composite material (SSC), containing the steel slag, metakaolin and cement, was proposed to replace the traditional cement for the stabilisation of soft clays in deep mixing ...
TL;DR: A short review on some models found in the literature with a theoretical background is provided in this paper, highlighting the advantages and the limitations of each approach presented, and a brief overview on emerging approaches is presented as well.
Abstract: Jet grouting is a known ground improvement technique largely used worldwide for different applications. One of the major limitations of this technique is mainly related to obtaining good predictions of the geometry of the final grouted body, as it is a function of the injection parameters and soil properties. Over the years, many studies have been conducted and few models and design methodologies have been developed to obtain more accurate predictions. A short review on some models found in the literature with a theoretical background is provided in this paper, highlighting the advantages and the limitations of each approach presented. A brief overview on emerging approaches is presented as well.
TL;DR: In this paper, the meso-scale properties of granular materials were investigated under the drained biaxial loading path and it was shown that the macroscopic mechanical performance of the granular material can be associated with the evolution of the proportions of meso loops with 3 sides and mesoloops of number of side no less than 6.
Abstract: Macroscopic behaviours of granular materials derive from the fabric distribution and evolution. Two kinds of fabric in the meso-scale can be distinguished: column-like clusters, called force-chains, which carry a majority of the external loading; and the loop-like clusters, called meso-loops, cells enclosed inside by contact branches. Some significant features in the meso-scale and how they influence the macroscopic behaviour of granular materials are investigated under the drained biaxial loading path. Results show that: (1) the macroscopic mechanical performance of the granular material can be associated to the evolution of the proportions of (meso-loops with 3 sides) and (meso-loops of number of side no less than 6); (2) there exists a single mesoscopic topology as the signature of the critical state of granular materials; (3) the force-chains adjacent area is the main source and contributor of the global dilatancy of the granular material. Moreover, the instability of the idealised hexagonal loop, as ...
TL;DR: In this paper, the feasibility of using superabsorbent polymer (SAP) and polyethylene glycol (PEG) as curing agents for ordinary cement-based systems with water-to-cement ratio of.4 and above has been investigated.
Abstract: The feasibility of utilising “Superabsorbent Polymer (SAP)” and “Polyethylene glycol (PEG)” as curing agents for ordinary cement-based systems with water-to-cement ratio of .4 and above has been investigated. The investigation considers water-to-cement ratios of .4, .5 and .6 and curing ages of 3, 7 and 28 days. A commercially available SAP of 300 μm average particle size and a laboratory grade PEG with an average molecular mass of 6000 have been used as curing agents. The impact of SAP and PEG dosages on consistency, setting time and degree of hydration of paste samples has been evaluated. The evolution of strength, water absorption and water retention characteristics has been studied using mortar samples and compared with respect to water- and air-cured control. SAP doses in the range of .3–1.0% of cement mass have been found to be effective over the full range of water-to-cement ratio tested. PEG admixed at the rate of .5–2.0% has been found to be beneficial at .50% dose for water-to-cement ratio of .4...
TL;DR: In this article, the first results of the water effect on the behavior of such a material interface are presented, and the final fracture length of the specimen and the corresponding curve of force-displacement highlight the influence of water immersion on the debonding failure mode.
Abstract: Considering that water may cause a separation of interfaces between layers of pavement structures, specific test on bi-layer specimens is performed in a water bath. For the study of the bond between layers made of cement concrete overlay on bituminous material, four-point bending results show a competition between different failure mechanisms. Actually a very good bond resistance between layers compared to the fracture tension resistance of the cement concrete layer is preliminary observed in dry conditions. In this work, first results of the water effect on the behaviour of such a material interface are presented. The final fracture length of the specimen and the corresponding curve of force-displacement highlight the influence of water immersion on the debonding failure mode. The field displacement measurement obtained by Digital Image Correlation is used to improve the understanding of the fracture scenario.
TL;DR: In this paper, a PVD-DCM method combined with prefabricated vertical drains (PVDs) and deep cement mixing (DCM) piles is presented based on the field case of Beijing-Shanghai high-speed railway in China.
Abstract: A PVD-DCM method combined with prefabricated vertical drains (PVDs) and deep cement mixing (DCM) piles is presented in this paper based on the field case of Beijing–Shanghai high-speed railway in China. The field performance of soft soil foundation improved by this method is comprehensively analysed, and shows that the PVD-DCM method takes full advantages of PVDs and DCM piles, in which the DCM piles increase the bearing capacity and reduce the total settlement of the soft foundation, while PVDs accelerate the consolidation of the soil by shortening the drainage paths. A plane strain numerical simulation on the field case is then conducted, which is converted by a three-dimensional (3D) problem with equivalent properties and dimensions. The numerical simulation is found to be an effective method to predict the true behaviour of the foundation improved by the PVD-DCM method, such as the load transfer and settlement, with reasonable accuracy. The PVD-DCM method is finally assessed both by PVD method and DCM...
TL;DR: In this article, a multiscale approach to analyse historical masonry buildings is presented and the numerical results deriving from its implementation are discussed, where a finite element description based on a generic anisotropic material is implemented.
Abstract: A multiscale approach to analyse historical masonry buildings is presented and the numerical results deriving from its implementation are discussed. The modelling of this kind of heterogeneous material composed by irregular, stones and mortar joints is performed at the level of the microstructure by also describing the nonlinear behaviour of stones and mortar joints through an elasto–plastic constitutive law. At the macro-level, a finite element description based on a generic anisotropic material is implemented. This micro–macro model aims to assess the structural behaviour and the safety condition of historic masonries.
TL;DR: In this paper, the small strain shear modulus Gmax and the damping ratio Dmin of sand-rubber mixtures with a small particles size ratio Sr (D50rubber/D50sand) were characterised by shear wave propagation using bender elements inserted in a modified triaxial cell.
Abstract: In this study, the small strain shear modulus Gmax and the damping ratio Dmin of sand–rubber mixtures with a small particles size ratio Sr (D50rubber/D50sand = .36) are characterised by shear wave propagation using bender elements inserted in a modified triaxial cell. The influence of addition of less than 50% rubber volume fractions Rf in a range of confining pressures varying from 50 to 500 kPa was investigated. The results showed that, for all confining pressures, the shear modulus decreases with increasing rubber volume fractions, while the damping ratio linearly increases. A quasi-conservation of shear modulus up to a volume fraction Rf = .2 and sharp decrease beyond this content is observed. The shear modulus decay and the damping enhancement with addition of rubber fractions are mitigated by increasing confining pressures. An optimal increase of the damping ratio without significant loss of rigidity and a minimal sensitivity to confining pressure for mixtures containing about 10% rubber is highligh...
TL;DR: In this article, an experimental investigation on the resistance to chemical attack (with sulphuric, hydrochloric and nitric acid) of several materials: OPC concrete, high-performance concrete, epoxy resin, acrylic painting and a fly ash-based geopolymeric mortar).
Abstract: This article presents results of an experimental investigation on the resistance to chemical attack (with sulphuric, hydrochloric and nitric acid) of several materials: OPC concrete, high-performance concrete, epoxy resin, acrylic painting and a fly ash-based geopolymeric mortar). Three types of acids with three high concentrations (10, 20 and 30%) were used to simulate long-term degradation. A cost analysis was also performed. The results show that the epoxy resin has the best resistance to chemical attack independently of the acid type and the acid concentration. However, the cost analysis shows that the epoxy resin-based solution is the least cost-efficient solution being 70% above the cost efficiency of the fly ash-based geopolymeric mortar.
TL;DR: In this paper, a new inhibitive pigment ZP containing zirconium compound obtained by chemical conversion (CC) method and cathodic protection to protect the steel rebars against localised corrosion in concrete.
Abstract: Deterioration of reinforcing concrete structures is a common problem among all the coast countries. Every year, several billion dollars are spent to repair and maintain reinforced concrete structures. Over time, the metal reinforcing bars used to improve the properties of concrete become susceptible to corrosion due to factors such as the presence of chloride and carbonation. Present work includes the use of novel anticorrosive coating. The use of zinc phosphate (ZP) coating has advantage of the low solubility of phosphates in medium- or high-pH solutions; also the resulting coating remains adhered to the metal surface even under extreme deformation. This study presents the efficiency of a new inhibitive pigment ZP containing zirconium compound obtained by chemical conversion (CC) method and cathodic protection to protect the steel rebars against localised corrosion in concrete. The corrosion behaviour of coated steel was assessed by open circuit potential, potentiodynamic polarisation and electrochemical...
TL;DR: In this paper, steel slag powder (SSP) and cement are mixed into muddy soft soil to improve the curing effect and the results show that although silica fume can improve the unconfined compressive strength (UCS) of SSP-cement solidified soil, the excitation effect is not ideal at low concentrations.
Abstract: To solve the problem of steel slag casually discard polluting the environment and to simultaneously increase the strength of sea muddy soil solidified with ordinary Portland cement, steel slag powder (SSP) and cement are mixed into muddy soft soil to improve the curing effect. SSP has low activity levels, so it needs to be activated. Through laboratory testing, the SSP activity levels were stimulated using different accelerators. The results show that although silica fume can improve the unconfined compressive strength (UCS) of SSP-cement solidified soil, the excitation effect is not ideal at low concentrations. The best observed effect occurs when caustic soda (NaOH) is added. Na2SO4 can also stimulate the activity of SSP, but this effect is weak; therefore, this activator needs to be used in combination with other catalysts. As the curing time increases, the UCS of the sample shows a certain correlation with the water content. The X-ray diffraction patterns of the SSP-cement hydrate were investi...
TL;DR: In this paper, the experimental study of capillary bridge properties with the use of analytical calculation of bridge profile, based on solution of Young-Laplace equation, is addressed, and the corresponding analytical solution is superposed and compared with image data.
Abstract: This article addresses the experimental study of capillary bridge properties with the use of analytical calculation of bridge profile, based on solution of Young–Laplace equation. Using the measurements of some parameters as the contact angle, half-filling angle and the neck radius of the capillary bridge between two spherical particles of radius r, the shape of the bridge is estimated using theoretical solutions of Young–Laplace equation. The corresponding analytical solution is superposed and compared with image data.