Effect of Different Mineralization Modes on Strengthening Calcareous Sand under Simulated Seawater Conditions

Calcareous sand, as a blow-fill or construction material, is widely used in island and reef construction projects in marine environments after treatment. When microorganism-induced mineralization is used to strengthen calcareous sand, salinity and other conditions in the marine environment will adversely affect microorganisms or their mineralization process. For this reason, the two environmental conditions created by deionized water and simulated seawater were introduced to explore their effects on the growth and urease activity of Sporosarcina pasteurii. Then, the changes in the permeability and mechanical strength of calcareous sand under different mineralization methods were compared by one-dimensional sand column tests. Finally, the reinforcement mechanism was compared and analyzed based on the results of scanning electron microscopy and X-ray diffraction tests. The results show that Sporosarcina pasteurii can induce carbonate and phosphate precipitation and mineralization to strengthen calcareous sand in simulated seawater. The mineralized products greatly reduce the permeability of calcareous sand and significantly improve the mechanical strength by wrapping calcareous sand particles, filling water seepage channels and cementing adjacent particles. The reinforcement effect of carbonate mineralization is better than that of phosphate mineralization, but phosphate mineralization has less impact on the environment during the treatment process.

Download Full-text

Carbonation Resistance of Surface Protective Materials Modified with Hybrid NanoSiO2

Coatings ◽

10.3390/coatings11030269 ◽

2021 ◽

Vol 11 (3) ◽

pp. 269

Author(s):

Kailun Xia ◽

Yue Gu ◽

Linhua Jiang ◽

Mingzhi Guo ◽

Lei Chen ◽

...

Keyword(s):

Construction Material ◽

Chemical Components ◽

Gravimetric Analysis ◽

X Ray Diffraction ◽

Carbonation Depth ◽

X Ray ◽

Carbonation Resistance ◽

Ideal Situation ◽

Caco3 Content ◽

Reference Samples

To date, reinforcement concrete is the main construction material worldwide. As the concentration of atmospheric CO2 is steadily increasing, carbonation of the reinforcement concrete becomes a pressing concern. In this study, novel surface protective materials (SPMs) modified with hybrid nanoSiO2 (HNS), fly ash, and slag were developed to reduce CO2 emissions and extend the service life of the reinforcement concrete. The carbonation depths were measured by phenolphthalein to reflect the carbonation resistance. X-ray diffraction (XRD), fourier-transform infrared spectroscopy (FTIR), and thermal gravimetric analysis (TGA) were conducted to analyze the chemical components of the samples after carbonation. In addition, MIP was carried out to examine the microstructures of the samples prior to carbonation. Thermodynamic modeling was employed to calculate the changes in the phase assemblages of each blends in an ideal situation. The experimental results showed that the carbonation depth and CaCO3 content of the SPM modified with HNS decreased by 79.0% and 64.6% compared with the reference, respectively. The TGA results showed that after carbonation, the CaCO3 contents were 4.40% and 12.42% in the HNS modified samples and reference samples, respectively. MIP analysis demonstrated that the incorporation of HNS in SPM led to a 48.3% and 58.5% decrease in big pores and capillary pores, respectively. Overall, the SPMs modified with HNS in this study possessed better carbonation resistance and refined pore structures.

Download Full-text

Use of Steel Industry Wastes for the Preparation of Self-Cleaning Mortars

Materials ◽

10.3390/ma12040621 ◽

2019 ◽

Vol 12 (4) ◽

pp. 621 ◽

Cited By ~ 3

Author(s):

José Balbuena ◽

Luis Sánchez ◽

Manuel Cruz-Yusta

Keyword(s):

Steel Industry ◽

Diffuse Reflectance ◽

Construction Material ◽

Added Value ◽

X Ray Diffraction ◽

X Ray ◽

Before And After ◽

New Material ◽

Lamination Process ◽

Self Cleaning

An important problem, which must be solved, is the accumulation of industrial waste in landfills. Science has an obligation to transform this waste into new products and, if possible, with high added value. In this sense, we propose the valorization of the waste which is generated in the steel lamination process (HSL) through its conversion into a new material with photocatalytic activity which is suitable for use as an additive to obtain a self-cleaning construction material. The valorization of steel husk lamination waste is achieved through a grinding process, which allows the sample to be homogenized, in size, without altering its phase composition, and a thermal treatment that turns it into iron oxide, which acts as a photocatalyst. These residues, before and after treatment, were characterized by different techniques such as PXRD (Powder X-Ray Diffraction), TGA (Thermogravimetric Analysis), SBET (Specific surface area, Brunauer-Emmett-Teller), SEM (Scanning Electron Microscopy) and Diffuse reflectance (DR). MB and RhB tests show that this material is capable of self-cleaning, both of the material itself and when it is incorporated into a construction material (mortar). In addition, the NOx gas elimination test shows that it is also capable of acting on greenhouse gases such as NOx.

Download Full-text

ANALISIS FAKTOR-FAKTOR YANG MEMPENGARUHI WAKTU TUNGGU PENGADAAN MATERIAL KONSTRUKSI PADA PROYEK GEDUNG DI KABUPATEN BADUNG

Jurnal Spektran ◽

10.24843/spektran.2016.v04.i02.p03 ◽

2016 ◽

Vol 4 (2) ◽

Author(s):

Putera Kumarayasa Mudita ◽

I K. Sudarsana ◽

Mayun Nadiasa

Keyword(s):

Lead Time ◽

Construction Projects ◽

Large Scale ◽

Construction Material ◽

Dominant Factor ◽

Building Projects ◽

Project Completion ◽

Factor I ◽

Material Procurement ◽

Material Transportation

Abstract :When undertaking construction projects, the smoothflow of materials to the project site must be maintained.Waiting for material, which frequently happens, will have a big impact, especially for large-scale projects that use a lot of labor. If the arrival of the materials is not in accordance with the schedule of material procurement planning, the workers will have nothing to do and the project cost will blow out and there will be delays in project completion time. This research investigates the factors which influence the lead time of construction material procurement in the Badung Regency. Data was obtained by distributing a questionnaire to 50 respondents. A research sample was obtained by purposive sampling aimed at the experts who work on building projects in the Badung regency. Before being used as a research instrument, the questionnaire was tested for the validity of data by using the Pearson Product-Moment correlation and its reliability was tested using the Cronbach alpha method. Processing and data analysis was conducted by Factor Analysis. The research results show there are twenty four variables identified that influence the lead time of construction material procurement on building projects in the Badung regency. All variables can be grouped into seven factors (Factor I, II, III, IV, V, VI, VII). The most dominant factor reviewed based on the percent of variance is Factor I which is formed by six variables being the material production process at the suppliers, the relationships between contractors and suppliers, a lack of material stock at the suppliers, the availability of material transportation, access to the project, and extreme topography.

Download Full-text

Effects of cement and foam addition on chemo-mechanical behaviour of lightweight cemented soil (LWCS)

E3S Web of Conferences ◽

10.1051/e3sconf/20199211006 ◽

2019 ◽

Vol 92 ◽

pp. 11006 ◽

Cited By ~ 2

Author(s):

Domenico De Sarno ◽

Enza Vitale ◽

Dimitri Deneele ◽

Marco Valerio Nicotera ◽

Raffaele Papa ◽

...

Keyword(s):

Mechanical Response ◽

Construction Material ◽

Thermo Gravimetric Analysis ◽

Water System ◽

Gravimetric Analysis ◽

X Ray Diffraction ◽

Thermo Gravimetric ◽

Soil Cement ◽

Strain Behaviour ◽

Insight Into

One of the main problems encountered in civil engineering is the management of large amounts of excavated soil, especially when the mechanical properties of this soil are not suitable for its reuse as a construction material. However, the excavated soil could represent a resource if appropriately improved. A suitable solution is the addition of cement and foam to produce lightweight cemented soils (LWCS). In this paper, an insight into the influence of foam on chemo-mineralogical and microstructural features of soil-cement-water system is presented. Time dependent mineralogical and microstructural changes have been monitored by means of X-Ray Diffraction, Thermo-gravimetric analysis and Mercury Intrusion Porosimetry. The present study shows that addition of foam does not alter the chemo-physical evolution of the soil-cement-water system. Large voids are present in the samples as footprint of air bubbles upon mixing, thus increasing porosity. Macroscopic behaviour of treated samples has been investigated by direct shear and oedometric tests. Chemo-physical evolution induced by cement addition is the major responsible for mechanical improvement showed by treated samples. Porosity of samples induced by foam addition plays a key role in the mechanical response of LWCS, inducing a transition of stress-strain behaviour from brittle and dilative to ductile and contractive as a function of increasing foam content.

Download Full-text

Effects of repeated hydraulic loads on microstructure and hydraulic behaviour of a compacted clayey silt

Canadian Geotechnical Journal ◽

10.1139/cgj-2018-0505 ◽

2020 ◽

Vol 57 (1) ◽

pp. 100-114 ◽

Cited By ~ 4

Author(s):

Arash Azizi ◽

Guido Musso ◽

Cristina Jommi

Keyword(s):

Hydraulic Conductivity ◽

Construction Projects ◽

Water Retention ◽

Construction Material ◽

Experimental Tests ◽

Climatic Conditions ◽

Earth Construction ◽

Hydraulic Behaviour ◽

Clayey Silt ◽

The Impact

Soils used in earth construction projects are mostly unsaturated, and they undergo frequent drying–wetting cycles (repeated hydraulic loads) due to changes in climatic conditions or variations of the ground water level, particularly at shallow depths. After compaction, changes in water content can significantly influence the hydromechanical response of the construction material, which therefore must be assessed for repeated hydraulic loads. This research investigates the effect of such loads on the microstructure and hydraulic behaviour of a silty soil, typically used in the construction of embankments and dykes, with the aim of providing a better understanding of the consequences of drying–wetting cycles on the response of the material over time. Experimental tests were performed to study the impact of drying–wetting cycles on the water retention, hydraulic conductivity, and fabric of compacted specimens. Fabric changes are documented to take place even without significant volumetric strains, promoting an irreversible increase in the hydraulic conductivity and a reduction in the capacity to retain water compared to the as-compacted soil. The fabric changes are interpreted and quantified by means of a hydromechanical model, which accounts for the evolving pore-size distribution at different structural levels. The proposed model reproduces quite well the microstructural observations, together with the evolution of the water retention behaviour and hydraulic conductivity.

Download Full-text

Identification and enhancement of the thermal and mechanical properties of two types of plasters successively derived from gypsum: from the Safi basin and the High Atlas of Marrakech, Morocco

10.5194/egusphere-egu2020-886 ◽

2020 ◽

Author(s):

imane baba ◽

Mounsif Ibnoussina ◽

Omar Witam

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Mechanical Strength ◽

Setting Time ◽

Density Measurement ◽

Raw Material ◽

Mechanical And Thermal Properties ◽

Thermal And Mechanical Properties ◽

X Ray Diffraction ◽

High Atlas

Over the past few decades, the construction industry has focused on sustainable, environmentally friendly and easily recyclable materials. The objective of this work is to characterize and enhance the thermal conductivity, mechanical strength and setting time of a composite material based on plaster and lime. This material is designed for use in plasters.Two types of gypsum are studied, the first one belongs to the Safi basin, the second one characterizes the High Atlas of Marrakech and precisely Douar Tafza. Geologically speaking, the two sites have many similarities. They are characterized by a Meso-Cenozoic age coverage covering a deformed Paleozoic age basement.The characterization of the plaster's raw material, gypsum, was necessary to determine its physical and geotechnical properties, mineralogy, thermal behaviour and microscopic structure. Several analyses have been developed such as: pycnometer density measurement, X-ray diffraction, infrared spectroscopy and scanning electron microscopy.We made samples, of standardized dimensions, of two mixtures based on the two types of plaster reinforced by the addition of two types of lime from different localities. The latter are from Marrakech and the Agadir region. The water/plaster mass ratio was set at 0.75 and the addition of lime was achieved by increasing its percentage in slices by 12.5% and up to 50%.The reinforcement of plaster with lime has enhanced its thermal and mechanical properties and setting time. The measurements show that the addition of lime has reduced the thermal conductivity and increased the mechanical strength of both types of plaster. In addition, following the addition of lime, the setting time has decreased and the basicity of the material has increased. Noting that the intrinsic properties of the raw material influence the mechanical and thermal properties of the material.Keywords: &#160;&#160;plaster, enhancement, properties, mechanical, thermal, Morocco

Download Full-text

Fabrication and Characterization of Alumina/Zirconia Ceramic Compound

Materials Science Forum ◽

10.4028/www.scientific.net/msf.724.249 ◽

2012 ◽

Vol 724 ◽

pp. 249-254 ◽

Cited By ~ 1

Author(s):

Bum Rae Cho ◽

Ji Hoon Chae ◽

Bo Lang Kim ◽

Jong Bong Kang

Keyword(s):

Mechanical Properties ◽

Fracture Toughness ◽

Low Temperature ◽

Mechanical Strength ◽

Sem Analysis ◽

Zirconia Ceramic ◽

Sintering Process ◽

Sintering Aids ◽

X Ray Diffraction

Sintered ZTA(zirconia toughened alumina) which has good mechanical properties at a low temperature was produced by milling and mixing with Al2O3 and ZrO2(3Y-TZP). In order to examine the effect of sintering aids on the mechanical properties of ZTA, fracture toughness and hardness of the produced ZTA were observed in accordance with change of the added quantity of ZrO2 Scanning electron microscopy and X-ray diffraction technique were applied to observe microstructural change and phase transformation during the process. Experimental results showed that the addition of sintering aids in ZTA at a low temperature induced densification and adding SiO2 and talc lowered sintering temperature and promoted crystallization process of the compound. The mechanical strength of ZTA added ZrO2 showed higher mechanical strength and SEM analysis revealed that Al2O3 and ZrO2 during the sintering process restrained the grain growth each other. Especially, the 92% Al2O3 added sintering aids showed more than 98% of the theoretical density and more than 1500 Hv of hardness value at a low temperature of 1400. It was also showed that the fracture toughness is gradually increasing first and decreasing later in accordance with the quantity of ZrO2.

Download Full-text

The relationship between microstructure and mechanical properties of directly bonded copper-alumina ceramics joints

Bulletin of the Polish Academy of Sciences Technical Sciences ◽

10.2478/bpasts-2014-0003 ◽

2014 ◽

Vol 62 (1) ◽

pp. 23-32 ◽

Cited By ~ 1

Author(s):

K. Pietrzak ◽

W. Olesinska ◽

D. Kalinski ◽

A. Strojny-Nedza

Keyword(s):

Mechanical Strength ◽

Transition Layer ◽

Diffraction Method ◽

Alumina Ceramics ◽

X Ray Diffraction ◽

X Ray ◽

Three Point Bending ◽

Microscopy Method ◽

Materials Used ◽

The Individual

Abstract The effect of phase transformations induced in the surface layer of alumina ceramics during its direct joining with copper activated with oxygen or titanium on the mechanical strength of the ceramic/copper joints was examined. The materials used in the experiments were an alumina single crystal, alumina ceramics (97.5 wt% Al2O3), the cermet mixtures: Cu-Cu2O with 10-50 wt% of Cu2O, copper with 5 wt% of Ti, and copper with 5 wt% of Ti and 10 wt% of Ag. The microstructure of the transition layer was examined by the X-ray diffraction method (XRD), scanning electron microscopy method (SEM) and energy dispersive x-ray spectroscopy (EDX). The mechanical strength of the joints was measured using the three-point bending method. The amount of oxygen optimal for the joining process was determined. It has been demonstrated that the cohesion of the joints depends not only on the formation of the individual phases but also, or even primarily, on the microstructure of the transition layer formed between them.

Download Full-text

Physical and Mechanical Properties of Non-Stoichiometric Cordierite with Treated FGD Sludge Addition Sintered at 1250°C

Journal of Physics Conference Series ◽

10.1088/1742-6596/2129/1/012091 ◽

2021 ◽

Vol 2129 (1) ◽

pp. 012091

Author(s):

Fatin Fatini Othman ◽

Banjuraizah Johar ◽

Shing Fhan Khor ◽

Nik Akmar Rejab ◽

Suffi Irni Alias

Keyword(s):

Mechanical Strength ◽

Physical And Mechanical Properties ◽

Xrd Analysis ◽

Solid State Reaction Method ◽

X Ray Diffraction ◽

High Mechanical Strength ◽

Practical Applications ◽

Porous Formation ◽

Sludge Waste ◽

Cordierite Ceramics

Abstract The effects of addition treated FGD sludge in non-stoichiometric cordierite, by benefiting from its high mechanical strength and good thermal performance, can hold promise for more practical applications of non-stoichiometric cordierite. Treated FGD sludge waste from borosilicate glass industrial were used as a flux to reduce the sintering temperature of cordierite. Cordierite ceramics were prepared using silica (SiO2), alumina (Al2O3), talc, kaolin, magnesia (MgO) and treated FGD sludge via solid-state reaction method. The cordierite were prepared by adjusting the ratio of FGD sludge and magnesia in the cordierite composition, respectively. 4 composition of cordierite with 0%, 1.5%, 3.0% and 4.5% of FGD sludge were prepared to obtain the formation of α-cordierite that can be determine by X-ray diffraction (XRD) analysis. Porosity, density, shrinkage and flexural strength for each of cordierite composition were determined to obtain the best composition of treated FGD sludge required for sintering aids of cordierite. Only FGD 3.0% able to synthesis pure α-cordierite while FGD 1.5 % shows an improvement in both porosity and density. The increasing amount of treated FGD sludge lead to decreasing in mechanical strength of cordierite ceramic due to porous formation.

Download Full-text

Granulation Of Porous Materials with Phase Change Material (PCM)

Budownictwo i Architektura ◽

10.35784/bud-arch.2780 ◽

2021 ◽

Vol 20 (3) ◽

pp. 135-144

Author(s):

Tomasz Bien

Keyword(s):

Mechanical Strength ◽

Phase Change ◽

Construction Industry ◽

Phase Change Materials ◽

Nitrogen Adsorption ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Method Of Production ◽

Adsorption Desorption ◽

Change Material

The paper describes the research on the method of production of granulated phase-change materials (PCM) used in construction industry for the accumulation of thermal energy. As mineral materials for the granules preparation zeolite from fly ash Na-P1 and natural diatomite dust were used which were impregnated with paraffinic filtration waste and granulated using a combined granulation method. Obtained granules were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption/desorption isotherm, and differential scanning calorimetry (DSC). Mechanical strength of the materials was determined in a “drop strength” test. Performed analyses revealed that mineral composition and micromorphology of the diatomite and zeolite granules were varied, with zeolite granules having higher mechanical strength.

Download Full-text