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Influence of Ultra Fine Glass Powder on the Properties and Microstructure of mortars

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Fluid Dynamics & Materials Processing 2024年第5期20卷 915-938页

作者： Wei Chen Dingdan Liu Yue Liang School of Civil Engineering Architecture and EnvironmentHubei University of TechnologyWuhan430068China

This study focuses on the effect of ultrafine waste glass powder on cement strength,gas permeability and pore structure.Varying contents were considered,with particle sizes ranging from 2 to 20μm.Moreover,alkali activation was considered to ameliorate the reactivity and cementitious properties,which were assessed by using scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDS),and specific surface area pore size distribution analysis.According to the results,without the addition of alkali activators,the performance of glass powder mortar decreases as the amount of glass powder increases,affecting various aspects such as strength and resistance to gas permeability.Only 5%glass powder mortar demonstrated a compressive strength at 60 days higher than that of the control group.However,adding alkali activator(CaO)during hydration ameliorated the hydration environment,increased the alkalinity of the composite system,activated the reactivity of glass powder,and enhanced the interaction of glass powder and pozzolanic reaction.In general,compared to ordinary cement mortar,alkali-activated glass powder mortar produces more hydration products,showcases elevated density,and exhibits improved gas resistance.Furthermore,alkali-activated glass powder mortar demonstrates an improvement in performance across various aspects as the content increases.At a substitution rate of 15%,the glass powder mortar reaches its optimal levels of strength and resistance to gas permeability,with a compressive strength increase ranging from 28.4%to 34%,and a gas permeation rate reduction between 51.8%and 66.7%.

关键词： mortar waste glass powder alkali activation compressive strength gas permeability pore structure

Substitution of Aggregates in Concrete and mortar with Coltan Mining Waste: Mechanical, Environmental, and Economic Impact Case Study

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Journal of Minerals and Materials Characterization and Engineering 2024年第2期12卷 139-163页

作者： Alinabiwe Nyamuhanga Ally Élodie Ruffine Zang Masika Muhiwa Grâce Manjia Marcelline Blanche Ursula Joyce Merveilles Pettang Nana Ngapgue François Bella Nabil Chrispin Pettang Laboratory Engineering Civil and Mechanics Doctoral Research Unit for Engineering and Applications University of Yaound&#233 I Yaound&#233 Cameroon Department of Civil Engineering Faculty of Applied Sciences and Technologies Free University of Great Lakes Countries (ULPGL) Goma DRC Department of Civil Engineering National Advanced School of Engineering of Yaoundé University of Yaoundé I Yaoundé Cameroon Department of Civil Engineering Fotso Victor University Institute of Technology University of Dschang Bandjoun Cameroon FIMAS Laboratory Faculty of Technologies Tahri Mohamed University Bechar Algeria

The mining process involves drilling and excavation, resulting in the production of waste rock and tailings. The waste materials are then removed and stored in designated areas. This study aims to evaluate the mechanical strength and the environmental and economic impact of using Coltan Mining Waste (CMW) as a substitute for aggregates in concrete and mortar production. To achieve this, the CMW needs to be characterised. The Dreux Gorisse method was primarily used to produce concrete with a strength of 20 MPa at 28 days. The mortars, on the other hand, were formulated according to the NF P 18-452 standard. The environmental impact of using CMW as substitutes for natural aggregates in the production of concrete and mortar was analysed using SimaPro software. The results showed that mortars and concrete made with CMW have comparable compressive strengths to the reference mortar and concrete;reduce the negative impact on ecosystem quality, human health, resources, and climate change. It has also been shown that the substitution of aggregates by CMW reduces the cost of concrete and mortar as a function of the distance from the aggregate footprint.

关键词： Aggregate Coltan Mining Waste Concrete mortar Mechanical Strength Life Cycle Analysis

Manufacturing of high-performance light-weight mortar through addition of biochars of millet and maize

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Waste Disposal and Sustainable Energy 2023年第1期5卷 97-111页

作者： Seemab Tayyab Anwar Khitab Abdullah Iftikhar Raja Bilal Nasar Khan Mehmet Serkan Kirgiz Department of Civil Engineering Mirpur University of Science and Technology(MUST)Mirpur10250AJ&KPakistan Department of Architecture Faculty of Engineering and Natural Sciencesİstanbul Sabahattin Zaim UniversityIstanbul34303Turkey

Agricultural wastes are environmental hazards,as these wastes can catch fire,resulting in the loss of human and animal lives and properties.Alternatively,the wastes are dumped in large spaces,which are already limited.Cementitious composites are quasi-brittle and develop cracks at the micro and nano level,which affect their strength,durability,and esthetics.Transforming agricultural wastes to biochar and using it as fibers in cementitious materials for crack arresting and enhancing fracture toughness is an environment-friendly approach.In this research,nano to microscale carbonaceous inert fibers(biochar)of millet and maize were prepared through pyrolysis followed by ball milling.The X-ray spectroscopy(EDX)revealed that 82.08%and 86.89%of the carbon content was retained in millet and maize,respectively.The scanning electron microscope(SEM)confirmed the presence of angular,flaky,and needle-like particles in the carbonaceous inerts,which may enhance the strength and the fracture response of the cementitious materials.These inerts were added individually to mortar specimens at dosage levels of 0,0.025%,0.05%,0.08%,0.2%and 1%by mass of cement.The dispersion of the synthesized nano inerts was ensured by UV–VIS spectroscopy.The compressive strength,flexural strength,porosity,and fracture toughness of cement mortar were evaluated.The carbonized nano intrusions reduced the porosity and density of the mortar specimens.The minimum porosity was noted with 1%and 0.08%dosages of millet and maize,respectively,whereas the minimum density was observed at 1%dosage for both.An increase in compressive and flexural strengths was also noticed.The compressive strength increased by 32%and 28%with 0.2%and 0.5%millet and maize,respectively.An increase of 168%and 114%in fracture toughness was noticed at optimized dosages of 0.5%and 1%of maize and millet,respectively.It is concluded that the addition of carbonaceous inert fibers of millet and maize resulted in light-weight porous mortars with enhanced strength and fracture toughness.The fr

关键词： mortar Biochar Carbon sequestration Lightweight Strength Fracture toughness

Strain Rate Effect of AE Characteristics in the Whole Process of Uniaxial Tensile of mortar

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Journal of Wuhan University of Technology(Materials Science) 2023年第3期38卷 547-556页

作者：王娜王岩 SU Yihui ZHAO Haitao College of Civil Engineering and Transportation Hohai UniversityNanjing 210024China

We completed the uniaxial tensile test of mortar in the range of strain rate from 10^(-6)to 10^(-4)s^(-1)in the section containing softening,and carried out acoustic emission monitoring(AE)simultaneously.A series of AE parameters and spectrum analysis methods were used to identify the damage evolution process and cracking mechanism of mortar at different strain rates.The results show that,with the increase of strain rate,the peak stress and tensile elastic modulus of mortar increase obviously,and the stress level corresponding to the starting point of AE activity increases significantly as well,which indicates that the mechanical properties and AE characteristics of mortar have obvious strain rate effect.With the increase of strain rate,the cumulative AE hit decreases gradually,while the average AE hit rate increases significantly,indicating that the increase of strain rate reduces the damage degree of internal microstructure of the specimen,but the crack propagation speed increases.In the pre-peak stress stage,the average of AE ringing count and signal energy decreases with the increase of strain rate,while the average of duration increases;in the post-peak stress stage(f_(t)-30%f_(t)),the average of the three AE parameters all increase with the increase of strain rate,indicating that the strain rate effect on the damage process of mortar is different before and after peak stress,and the damage mechanism represented by different parameters is also different.In the whole process of uniaxial tensile of mortar,with the increase of strain rate,the scatter distribution of AE frequency-amplitude becomes more discrete,and the b-value shows a decreasing trend.In addition,the average level of AE peak frequency decreases with the increase of strain rate,while that of ca8 band wavelet energy spectrum coefficient increases.It is indicated that the increase of strain rate enables the crack propagation state of mortar specimen to become unstable,and the width of macrocrack increases but the proportion decreases.

关键词： mortar acoustic emission uniaxial tension strain rate

Experimental Evaluation of Compressive Strength and Gas Permeability of Glass- Powder-Containing mortar

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Fluid Dynamics & Materials Processing 2023年第10期19卷 2639-2659页

作者： Yue Liang Wenxuan Dai Wei Chen School of Civil Engineering Architecture and EnvironmentHubei University of TechnologyWuhan430068China

Glass powder of various particle sizes(2,5,10 and 15μm)has been assessed as a possible cement substitute for mortars.Different replacement rates of cement(5%,10%,15%,and 20%)have been considered for all particle sizes.The accessible porosity,compressive strength,gas permeability and microstructure have been investigated accordingly.The results have shown that adding glass powder up to 20%has a signiﬁcantly negative effect on the porosity and compressive strength of mortar.The compressive strength initially rises with a 5%replacement and then decreases.Similarly,the gas permeability of the mortar displays a non-monotonic behavior;ﬁrst,it decreases and then it grows with an increase in the glass powder content and particle size.The porosity and gas permeability attain a minimum for a 5%content and 10μm particle size.Application of a Nuclear magnetic resonance(NMR)technique has revealed that incorporating waste glass powder with a certainﬁneness can reduce the pore size and the number of pores of the mortar.Compared with the control mortar,the pore volume of the waste glass mortar with 5%and 10μm particle size is signiﬁcantly reduced.When cement is partially replaced by glass powder with a particle size of 10μm and a 5%percentage,the penetration resistance and compressive strength of the mortar are signiﬁcantly improved.

关键词： Waste glass powder mortar porosity gas permeability compressive strength NMR

On the Combination of Silica Fume and Ceramic Waste for the Sustainable Production of mortar

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Fluid Dynamics & Materials Processing 2023年第5期19卷 1083-1090页

作者： Zine El Abidine Rahmouni Mekki Maza Nadia Tebbal Messaouda Belouadah Civil Engineering Department Faculty of TechnologyM’sila UniversityM’sila28000Algeria Institute of Technical Urban Management M’sila UniversityM’sila28000Algeria

The combined use of silica fume(SF)and ceramic waste(CW)for the production of mortar is studied.Sand is replaced by 5%,10%,15%and 20%of CW while a fixed 5%percentage(%wt of cement)of SF is used.The results show that the best results are obtained by using silica fume and ceramic waste sand with 15%weight of sand and 5%wt of cement.With the addition of sand ceramic waste(SCW),the mortar compressive strength and density increase,while the porosity displays an opposite trend.The experimental analysis is complemented with theoretical considerations on the matrix strength and related improvements in mechanical behavior.It is shown that the agreement between the experimental values and the estimated values is good.

关键词： mortar silica fume ceramic waste full factorial arrangement mechanical properties

The Effect of Different Freeze-Thaw Cycles on mortar Gas Permeability and Pore Structure

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Fluid Dynamics & Materials Processing 2023年第6期19卷 1623-1636页

作者： Wei Chen Ao Xu Hejun Zhang Mingquan Sheng Yue Liang Frederic Skoczylas School of Civil Engineering Architecture and EnvironmentHubei University of TechnologyWuhanChina CNRS Centrale LilleUMR9013-LaMcube-Laboratoire de Mécanique Multiphysique et MultiéchelleUniversitéde LilleLilleFrance

Two different freeze-thaw cycles(FTC)are considered in this study to assess the related impact on gas permeability and micro-pore structure of a mortar.These are the water-freezing/water-thawing(WF-WT)and the air-freezing/air-thawing(AF-AT)cycles.The problem is addressed experimentally through an advanced nuclear magnetic resonance(NMR)technique able to provide meaningful information on the relationships among gas permeability,pore structure,mechanical properties,and the number of cycles.It is shown that the mortar gas permeability increases with the number of FTCs,the increase factor being 20 and 12.83 after 40 cycles for the WF-WT and AF-AT,respectively.The results also confirm that gas permeability hysteresis phenomena occur during the confining pressure loading and unloading process.

关键词： mortar freeze-thaw cycles gas permeability pore structure NMR mechanical properties

Effects of Cationic Surfactant on Fresh and Hardened Properties of Cement-Based mortar

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Journal of Renewable Materials 2023年第5期11卷 2345-2365页

作者： Soumaya Zormati Fadhel Aloulou Habib Sammouda Laboratory of Energy and Materials LabEM-LR11ES34University of SousseSousseTunisia

The objective of this study is to analyze the effects of using surfactant(CTAB)and cellulose nanofibers(NFC)as an admixture in cement mortars.We examined composite properties as porosity,compression energy,thermal conductivity and hydration.The results showed that with the addition of 0.7%by weight of NFC per emulsion in the presence of a cationic surfactant(CTAB).The new material produced presented a dry porosity between 4.7%and 4.4%,compressive strength between 9.8 and 22.9 MPa,and thermal conductivity between 0.95 and 2.25 W·m^(−1)·K^(−1).Thus we show better mechanical and thermal performance than that traditional Portland cement mortar with a density similar.In addition,the mortar made by emulsion of ordinary portland cement,cellulose nanofiber and organophilic clay(OC)treated with cetyltrimethylammonium bromide(CTAB)obtained has good resistance under high temperature and water,as well as excellent thermal insulation performance under high temperature and humidity conditions.This study verified that the presence of NFC promotes hydration,leading to the production of more calcium silicate and portlandite gel.

关键词： Cement nanofiber cellulose organophile-clay thermal conductivity hydration surfactant compressive strength mortar

Chloride-binding capacity of mortars composed of marine sand subjected to external chloride penetration

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Journal of Oceanology and Limnology 2022年第4期40卷 1462-1471页

作者： Congtao SUN Ming SUN Tao TAO Feng QU Gongxun WANG Peng ZHANG Yantao LI Jizhou DUAN Key Laboratory of Marine Environmental Corrosion and Bio-fouling Institute of OceanologyChinese Academy of SciencesQingdao 266071China School of Civil Engineering Qingdao University of TechnologyQingdao 266033China School of Civil Engineering Hunan University of Science and TechnologyXiangtan 411201China Open Studio for Marine Corrosion and Protection Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China Nantong Research and Development Center of Marine Science and Technology Institute of OceanologyChinese Academy of SciencesNantong 226004China

In order to explore the interactional relations of internal chloride and external chloride-binding amongst the cementitious materials,the chloride-binding capacity of mortars composed of marine sand(MS)or washed marine sand(WMS)were investigated.Results indicate that more external chloride can penetrate and diff use more deeply into the WMS mortar than that in the MS mortar.This phenomenon suggests that the external chloride migration resistance due to WMS is lower than that caused by MS.The distribution trends of the bound chloride content in the two types of mortars are the same at diff erent immersion times.However,a signifi cantly decreased area of the bound chloride content exists at the border of the external penetration area(EPA)and the external unaff ected area(EUA)at the immersion ages of 3 and 7 d,and then it disappears gradually with immersion time.The WMS mortar can bind more external chloride,whereas the MS mortar can bind more internal chloride,at diff erent immersion times.The distributions of bound chloride conversion rate in the EPAs of the two types of mortars diff er across immersion times.The distribution fi rstly decreases,and then it increases at the immersion ages of 3 and 7 d.The distribution was from increase,then decreases,and increase again at the immersion ages of 28 and 56 d.The bound chloride conversion rate in the WMS mortar is aff ected more greatly by external chloride penetration than that in the MS mortar.The amounts of the Friedel’s salt tend to increase with prolonged immersion time.Finally,the penetration of external chloride can increase the amount of fi ne capillary pores smaller than 100 nm in the WMSmortar exposed for 56 d in the chloride salt solution(WMS-E)specimen.

关键词： marine sand mortar chloride binding Friedel’s salt pore structure