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

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%.

Frost Resistance of Pervious Concrete Mixed with Waste Glass Powder

The contents of waste glass powder(WGP)(0%,10%,15%,20%,25%)and water-binder ratio(W/C)(0.24,0.26,0.28)were used as influencing factors,and the quality loss rate(Δm)and compressive strength loss rate(Δfc)were used as characterization parameters.The Ca/Si ratio and main element contents of C-S-H gels with different WGP content were investigated by energy dispersive spectrometry(EDS).The pore structure evolution characteristics of WGP composite cementing materials were investigated by low field nuclear magnetic resonance(NMR).UsingΔfc as the index of frost resistance degradation and Weibull function,the frost resistance degradation of glass doped pervious concrete(WGP-PC)was modeled.The results show that,with WGP,for the same number of cycles,Δm andΔfc decrease and increase with the increase of WGP.Under the same WGP content,Δm andΔfc decrease first and then increase with the increase of W/C.After 100 freeze-thaw cycles,the samples with WGP content of 20%and W/C of 0.26 have the best freeze-resistance.Microscopic tests show that with the increase of WGP content,the Ca/Si ratio of C-S-H gel decreases at first and then increases with the increase of WGP content.The extreme value of Ca/Si is 2.36 when WGP is added by 20%.The pore volume of hardened paste with 20%WGP content decreased by 18.6%compared with that of cement system without WGP.The overall compactness of the specimen was improved.On the basis of the test data,a life prediction model was established according to Weibull function.The experiment showed thatΔfc could be used as a durability degradation index,and the slope of the reliability curve became gentle after WGP was added,which reduced the damage degradation rate of PC.W/C was 0.26.It's about 5000 hours.

Early-Age Properties Development of Recycled Glass Powder Blended Cement Paste:Strengths,Shrinkage,Nanoscale Characteristics,and Environmental Analysis

Recycling solid waste in cement-based materials cannot only ease its load on the natural environment but also reduce the carbon emissions of building materials.This study aims to investigate the effect of recycled glass powder(RGP)on the early-age mechanical properties and autogenous shrinkage of cement pastes,where cement is replaced by 10%,20%and 30%of RGP.In addition,the microstructure and nano-mechanical properties of cement paste with different RGP content and water to binder(W/B)ratio were also evaluated using SEM,MIP and nanoindentation techniques.The results indicate that the early-age autogenous shrinkage decreases with the increase of RGP content and W/B ratio.While the mechanical strength deteriorates due to the addition of RGP,it can be compensated by reducing the W/B ratio.Although the addition of RGP increases the total porosity of the hardened paste,it reduces the small size porosity(<50 nm).In addition,the proportions of different types of C-S-H are changed,and the volume fraction of porosity is increased,but that of hydration products of cement paste is reduced due to the incorporation of RGP.Besides its pozzolanic activity,the mitigated shrinkage deformation that RGP is generating in cement pastes is encouraging for its use as a novel supplementary cementitious material that reduces the early-age cracking risk of cement-based materials.Meanwhile,the life cycle assessments indicate that the RGP-cement component is an economical and eco-friendly novel engineering material.

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

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.

Effect of Glass Powder on Chloride Ion Transport and Alkali-aggregate Reaction Expansion of Lightweight Aggregate Concrete

The effects of glass powder on the strength development, chloride permeability and potential alkali-aggregate reaction expansion of lightweight aggregate concrete were investigated. Ground blast furnace slag, coal fly ash and silica fume were used as reference materials. The re- placement of cement with 25% glass powder slightly decreases the strengthes at ？ and 28 d, but shows no effect on 90 d＇s. Silica fume is very effective in improving both the strength and chloride penetration resistance, while ground glass powder is much more effective than blast furnace slag and fly ash in improving chloride penetration resistance of the concrete. When expanded shale or clay is used as coarse aggregate, the concrete containing glass powder does not exhibit deleterious expansion even if alkali-reactive sand is used as fine aggregate of the concrete.

Strength and Microstructure of Mortar Containing Glass Powder and/or Glass Aggregate

The compressive strength of mortar containing glass powder（GP） and/or glass aggregate（GA） was tested, and its microstructure was also studied by thermogravimetric and differential thermal analysis（TG-DTA）, scanning electron microscopy（SEM）, energy dispersive spectroscopic analysis（EDX）, and X-ray diffraction（XRD） techniques. The incorporation of GA would decrease the compressive strength of the mortar in the absence of GP. Incorporating both GA and GP could change the hydration environment, promote pozzolanic reaction of GP and improve the compressive strength. GP does not lead to but can effectively control ASR（Alkali Silica Reaction）. GP and GA do not transform the type of hydrates, but have a great influence on the amounts of hydration products, and generate more calcium silicate hydrate（C-S-H gel） with lower Ca/Si ratio. GP and GA with good gradation will make the microstructure denser.

Effect of Glass Powder on Concrete Sustainability

As defined by the American Concrete Institute (ACI), alternative supplementary cementitious materials (ASCMs) and local materials are very important in concrete sustainability. As an ASCM, glass powder (GP) shows excellent pozzolanic properties. This paper focuses on characterization and the effect of GP on concrete properties compared to those of Class F fly ash (FFA) and ground granulated blast furnace slag (GGBS). Concrete incorporating 0, 20 and 30% of GP and other concrete mixes containing 30% of FFA or GGBS were cast. The concrete mixes considered in this study have water to binder (w/b) mass ratio ranging from 0.35 to 0.65. The mechanical properties such as compressive strength and durability including chloride ions permeability and chloride ions diffusion are evaluated. The results show that GP develops effects on mechanical properties similar to those of FFA and performs better than GGBS and FFA in terms of permeability reduction. GP reduces dramatically chloride permeability of concrete regardless w/b ratio, favoring an improvement of the concrete durability. Because of the interesting permeability developed by concretes incorporating GP, its use as an ASCM is promising.

Effect of Sand Partial Substitution for Glass Powder on the Behaviour of Sand-Cement Mortar

Partial substitution of aggregates for pieces of glass in concrete contributes to reducing the use this resource and preserving the environment for future generations. However, concretes or mortars mixed with crushed glass can deteriorate within a few years, because of the alkali-silica reaction related to the size of glass pieces. Some investigations were carried out in order to find out how to bring down this phenomenon. Different percentages of glass powder were mixed with mortar made from sand, cement and crushed glass pieces of which diameter is between 1 and 5 mm. Products obtained were submitted to flexural testing, compressive strength testing and resistance to acid attack and Scanning Electron microscopy (SEM) observations were made after a period running from 28 to 180 days of drying. The results show an increase in the mechanical properties of products with glass powder and an improvement in the durability of mortar in acidic environment. Such improvements are related to the enhanced adhesion created between crushed glass pieces and cementitious matrix containing glass powder as a result of pozzolanic reaction.

Reactivity of Recycled Glass Powder in a Cementitious Medium

The reactivity of the recycled glass powder (GP) in a cementitious medium has been studied over time by means of X-ray diffraction and thermal gravimetric analysis. Two different mixtures based on cement/glass powder (0 or 20 wt% GP) and lime/glass powder (70 wt% GP) were considered. Analysis revealed the coexistence of both hydration and pozzolanic reaction during the hardening of the mortars. At young age, the cement hydration would prevail over the pozzolanic one resulting in a decrease of physico-chemical and mechanical properties of the material due to the dilution effect. The pozzolanic reaction that predominates from 91 days, would induce the formation of supplementary C-S-H leading to improve the material properties.

Effect of Mitigating Strength Retrogradation of Alkali Accelerator by the Synergism of Sodium Sulfate and Waste Glass Powder

This work aims to utilize waste glass powder(WGP)as a plementary material to mitigate the strength shrinkage caused by the alkaline accelerator.Waste glass power was used to replace cement by 0%,10%,and 20%to evaluate waste glass powder on the alkaline accelerator’s strength retrogradation.The results show that the strength improvement effect of unitary glass powder is inconspicuous.Innovative methods have been proposed to use sodium sulfate and waste glass powder synergism,using the activity of amorphous silica in glass powder.Compared with the reference group,the compressive strength of 28d mortar increases by 67%when the sodium sulfate content is 2.5%,and the replacement amount of waste glass powder is 10%.Besides,XRD and SEM analysis of hydration products also confirmed that the synergistic effect of sodium sulfate and waste glass powder could reduce strength inversion.The findings presented in this paper are pivotal for using waste glass to solve the problem of strength inversion caused by the alkaline accelerator.

Effects of Wood Ash and Waste Glass Powder on Properties of Concrete in Terms of Workability and Compressive Strength in Jaresh City

The potential for using fly ash as a supplementary cementing material in concrete has been known almost since the beginning of the previous century. Fly ash was used as a supplementary cementing material (SCM) in the production of Portland cement concrete. A supplementary cementing material, when used in conjunction with Portland cement, contributes to the properties of the hardened concrete through hydraulic or pozzolanic activity, or both. In this study, the fly ash and waste glass powder were used in concrete blocks to study the improvement of concrete in terms of workability and strength. Therefore, an experimental study will be conducted to measure the engineering properties of cured concrete. In this research, local raw material from Jaresh area was used.

PHLOGOPITE GLASS CERAMIC BY POWDER SINTERING PROCESS

Phlogopite glass ceramics can be made by powder sintering technology. This paper now studies the factors which affect properties of the sintered phlogopite glass ceramic by X-ray diffraction in qualitative and quantitative way, and discusses the method improved the machinable properties of phlogopite glass ceramic. (Author abstract)

Study on the Physical and Mechanical Properties of Al-Powder Reinforced Bioactive Glass: Ceramic Composite Material

Glass-ceramic samples, having composition of SiO2-35, CaO-45, Na2O-10 and P2O5-10 in weight ratio were prepared through sintering route. Glass powder was reinforced by Al powder. The strength of glass-ceramic composite was found to be temperature dependent, and it varies with the addition of Al powder. Flexural strength increases with the increase of powder addition and sintering temperature, however, decreases with the increase of sintering time. There is an optimum temperature (>1100℃) above which flexural strength of all samples decreases. Bulk density changes to a higher value as the addition of Al-powder increases up to 3% by weight above which density decreases slowly. On the other hand, apparent porosity and water absorption decrease with the increase of percentage of Al powder added. Porosity and water absorption also showed a dependent characteristic on sintering time and sintering temperature.

Influence of Recycling Waste Glass as Fine Aggregate on the Concrete Properties

Recent years have witnessed an increase in the quantity of waste glass(WG)across the globe.Replacing the fine aggregate with WG is one of the steps toward preserving the natural resources of the environment and creating low-cost concrete.The present study is concerned with replacing fine aggregates with glass powder(GP)at(0%,15%,30%,and 50%).It has studied the fresh and hardened properties(compressive strength,tensile strength,hardened density,and slump)for all the mentioned percent replacements.The findings have shown that all mixtures containing GP gave acceptable slump results within the design limits(2–5 cm)according to ACI standard 211.1.It has been observed that increasing the proportion of GP led to a decrease in the weight of concrete.Lastly,replacing GP with sand by 30%has led to an increase in the compressive strength by about 2.4%and 12.45%,and the tensile strength by about 2.5%and 26.54%at 7-and 28-d,respectively in comparison to normal concrete.

废弃玻璃粉风积沙混凝土柱抗震性能试验研究

为研究玻璃粉等质量取代20%水泥与风积沙等质量取代30%天然砂对混凝土柱抗震性能的影响,本文设计和制作4根混凝土柱试件。第1根是普通混凝土柱,第2根是玻璃粉等质量取代20%水泥的混凝土柱,第3根是风积沙等质量取代30%河砂的混凝土柱,第4根是同时用玻璃粉和风积沙分别等质量取代20%水泥和30%河砂的混凝土柱。通过低周往复荷载试验,对比分析各个试件的破坏形态、承载力、滞回性能、骨架曲线、耗能能力、延性系数、刚度退化规律和变形特点。结果表明:20%取代率的玻璃粉取代水泥和30%取代率的风积沙取代天然河砂均能提高混凝土柱的抗震性能,降低构件破坏程度;基于试验结果、Fajfar和Park-Ang提出的地震损伤模型,对其耗能因子β进行修正,得到了修正后的Park-Ang损伤模型,并与废弃玻璃粉风积沙混凝土柱的试验过程吻合较好。

复合盐冻侵蚀下玻璃粉对混凝土孔隙结构影响分析

玻璃粉作为掺合料用于混凝土的改良已得到广泛关注和研究,然而关于复合盐溶液冻融循环下玻璃粉混凝土的孔隙结构特征尚未形成一致认识。针对不同玻璃粉掺量下的混凝土试样,开展室内复合盐溶液冻融循环试验和CT扫描试验,分析了不同玻璃粉掺量下混凝土孔隙结构特征参数分布变化规律,进一步揭示复合盐冻侵蚀下玻璃粉对混凝土细观损伤特征的影响机理。结果表明,玻璃粉掺量增加一定程度上降低了因复合盐冻侵蚀导致的混凝土孔隙结构分布波动变化;10%掺量的玻璃粉对混凝土受复合盐冻损伤影响抑制效果相对更好。相关研究成果可为盐冻环境下混凝土结构冻融侵蚀损伤防治及玻璃粉固废材料的资源化利用提供一定的理论支撑。

添加复合稀释剂的低爆速乳化炸药的制备及性能

以玻璃微球和滑石粉共同作为稀释剂制备一种低爆速乳化炸药。观察不同质量分数的玻璃微球和滑石粉对乳化炸药形貌的影响,并对乳化炸药的爆速、猛度、空中爆炸冲击波压力及储存稳定性进行测试。实验结果表明,随着滑石粉质量分数的增加,乳化炸药的形貌由乳胶状逐渐向颗粒状转化,爆速呈线性下降,对玻璃微球质量分数为5%、10%、15%的乳化炸药,测得最低爆速分别为3440、2740、2188 m/s。而随着滑石粉质量分数的增加,猛度、空中爆炸冲击波峰值超压均呈非线性下降,当滑石粉控制在一定量时,冲击波正压作用时间变化不大,乳化炸药储存稳定性较好。这种低爆速乳化炸药成本低廉、爆轰性能可调、储存稳定性好,具有较好的实用性。

碱激发低碳混凝土的力学性能与提升机理研究

针对水泥在生产利用过程中产生的碳排放问题及固废材料在大掺量条件下替代水泥制备混凝土导致其力学性能下降的问题,利用4%Na_(2)SiO_(3)对玻璃粉(GP)进行碱激发处理,随后替代50%的水泥制备低碳混凝土。结果表明,低碳混凝土的力学性能远低于普通混凝土,而Na_(2)SiO_(3)掺入使低碳混凝土力学性能得到一定程度的提升,在各龄期内抗压强度分别提升了22.6%、27.5%、19.8%和17.2%;劈裂抗拉强度增长了21.3%、20.6%、18.2%和16.3%。Na_(2)SiO_(3)使玻璃粉(GP)中丰富的SiO_(2)在OH-的作用下出现较为明显的解构现象,使其在低碳混凝土内部与Ca、Na、K等元素结合生成了更多的C-S-H凝胶、C-A-S-H凝胶、N-A-S-H凝胶,同时还产生了强度更高的钾A型沸石晶体,使得低碳混凝土的大孔隙含量降低,孔隙结构得到优化,进而导致低碳混凝土力学性能得到大幅提升。研究为降低碳排放及固废在混凝土中大掺量的使用提供了新思路、新见解。

龙眼果粉的水分吸附特性研究

以龙眼果粉为对象,利用静态测量法测定其在不同温度下的吸湿等温线,探究在不同含水率下龙眼果粉的X射线衍射图谱及玻璃化转变温度,并通过数学方程计算其热力学特性参数,以揭示龙眼果粉的水分吸附特性。结果表明,龙眼果粉的吸湿等温线为Ⅲ型等温线,Peleg模型是龙眼果粉吸湿等温线的最佳拟合模型。在水分活度(water activity,A_(w))>0.69时,龙眼果粉水分吸附量显著增加,导致糖类晶体结构消失。龙眼果粉的吸附过程符合熵焓互补理论,其吉布斯自由能为1586.6 J/mol>0,表明可通过控制环境条件来控制龙眼果粉的吸附过程。干基含水率从0.054 g/g上升到0.350 g/g时,龙眼果粉的玻璃化转变温度起始点从14.6℃降低至-26.5℃,其终点从39.1℃下降至-5.8℃。25℃下龙眼果粉的理论最佳贮藏A_(w)为0.086,对应的干基含水率为0.0495 g/g。该研究结果可为龙眼果粉贮藏条件的选择提供参考。

玻璃粉和生物炭对砂浆塑性收缩及开裂行为的影响

为探究可再生材料对砂浆塑性收缩及开裂的影响,本文选取玻璃粉和生物炭两种可再生材料,采用数字图像相关技术(DIC)定量评估不同掺量(2%、4%、6%,占水泥质量分数)玻璃粉和生物炭对砂浆塑性收缩和开裂行为的影响。结果表明,掺玻璃粉和生物炭组砂浆最大裂缝宽度均小于未添加玻璃粉和生物炭的对照组,因此添加2%~6%玻璃粉或生物炭对砂浆的塑性收缩及开裂均起到积极作用。玻璃粉表面光滑疏水,提高了砂浆的流动性,其填充效应和火山灰活性减缓了塑性收缩。生物炭具有多孔结构和吸水性,降低了砂浆的流动性,有效减缓了塑性收缩。