Mineral Powder Research Articles

Characteristics of slow-release ice and snow melting micro-surfacing materials

ABSTRACT In order to solve the problem of frequent snow and ice removal in winter, a micro-surfacing pavement with active snow and ice removal and slow-release function is developed. The snow-melting agent with sodium acetate, calcium acetate, and potassium acetate as the main components was prepared, and the optimum proportion was determined. With the help of hygroscopicity and oil absorption tests, the optimum surface modifier and its optimum concentration were determined. The microstructure of the snowmelt agent were characterized by infrared spectroscopy and scanning electron microscopy. The influence of snow-melting agent on the road performance was explored. The results show that the optimum proportion of sodium acetate, calcium acetate and potassium acetate is 37, 15 and 48 % respectiveiy. When the surface modifier: hydrogen silicone oil and KH560 solution concentration was 4.0% and 1.0% respectively, the slow-release effect was the optimum. The wear resistance and high temperature stability of micro-surfacing with the snowmelt agent were increased by 2.5 % and 8.2 %, respectively. It is most reasonable to determine that the optimal replacement amount of mineral powder is 50%. It is necessary to study the distribution of self-made snowmelt agent in the mixture in the future.

Performance of geopolymer concrete activated by sodium silicate and silica fume activator

This study examined the properties (strength, workability and crack) of geopolymer concrete activated by sodium silicate and silica fume activator. Sodium silicate and sodium hydroxide (NaOH) are commonly activators used to make geological polymer composite. However, they will cause the decline of the performance of geopolymer concrete when it is prone to polymerization in the surrounding of alkaline. Silica fume can improve the workability and strength of geopolymer concrete. The Pearson correlation coefficient and experiment is used to study the performance of geopolymer concrete with sodium silicate and silica fume activator. The influence of two kinds of activators on the slump of geopolymers with different mix ratios was analyzed by Pearson correlation coefficient. The relative coefficient of mineral powder decreased from 0.785 to 0.409. The absolute relative coefficient of calcined magnesite decreased from 0.829 to 0.156. The correlation between slag, calcined magnesite and slump changed from significant to insignificant. The analysis shows that the slump of geopolymers with silica fume activator are less affected by mineral powder and calcined magnesite than that of sodium silicate activator. Geopolymer concrete have more stable performance with silica fume activator. The geopolymer concrete excited by silica fume activator compared with the sodium silicate activator, the cracks and internal porosities on the surface of the specimens are less. The compressive strength and crack of geopolymer concrete excited by silica fume activator reached 43.36 MPa and 0.095 mm, respectively, at 20 ℃ ± 2 ℃ and more than 95% humidity. It shows good early strength and less cracks. The experimental mix proportions are optimized to conduct the complex the equilibrium of physical and chemical reactions and to reinforce the mechanical property of geopolymer concrete with silicate fume activator.

Environmentally Friendly Concrete for Sustainable Overlays with Waste Mineral Powders: Problem Statement, Literature Survey, Economic Potential and Research Gaps

Environmentally Friendly Concrete for Sustainable Overlays with Waste Mineral Powders: Problem Statement, Literature Survey, Economic Potential and Research Gaps

Comparison of PuraStat self-assembling peptide hydrogel versus mineral-based Hemospray for endoscopic hemostasis of upper and lower gastrointestinal lesions in pigs

ObjectiveTo compare a RADA16-based self-assembling peptide hydrogel versus an inorganic powder-based spray device for controlling postoperative bleeding in upper and lower GI mucosal lesions in pigs.MethodsMultiple mucosal lesions were endoscopically-created in the stomachs and lower colons of six Yorkshire swine on Day 0. Three animals’ wounds were treated with 2.5% RADA16 solution (PuraStat®), two animals were treated with an aerosolized mineral powder (Hemospray®), and one animal was an untreated control. Primary outcomes were test article applications required to control initial bleeding, time-to-hemostasis, and rebleeding incidence. Secondary outcomes included animal recovery, and clinical pathology at weekly endoscopic evaluations and the 4-week study terminus.ResultsNumber of material administrations required and time-to-hemostasis was comparable between PuraStat and Hemospray groups. Rebleeding rates were comparable between treatments. Two of 12 (17%) Hemospray and none of 18 (0%) PuraStat stomach sites experienced rebleeding during the final 4 min of the 10-min observation period. No delayed bleeding was observed during weekly endoscopic follow-ups. Hematology and serology values remained normal in all animals. Histology showed expected healing responses at all PuraStat- and Hemospray-treated defects, with less inflammation than untreated sites. Histomorphological observations were comparable between different groups for both the stomach and colon for test and control materials, with lower inflammation scores than untreated sites. Performance and usability responses were generally good with both systems, although the Ability to Treat Intended Site score was significantly better with PuraStat in upper GI lesions.ConclusionsPuraStat and Hemospray were effective topical hemostats for mild-to-moderate bleeding in upper and lower GI wounds. Rebleeding was observed in two of 12 Hemospray-treated sites and none of 18 PuraStat-treated sites. PuraStat and Hemospray were associated with better wound healing than untreated controls. The ability to treat upper GI lesions was easier with the PuraStat versus Hemospray system.

A low-carbon alkali activated slag based ultra-high performance concrete (UHPC): Reaction kinetics and microstructure development

Ultra high performance concrete (UHPC) is a cement-based material with great development prospects. However, the production of cement will produce a large amount of CO 2 , which does not conform to the current global trend of energy conservation and emission reduction, and limits the further development of UHPC. One of the ways to further develop UHPC is to reduce the carbon emissions in the production process of UHPC. The aim of this study is to develop a low-carbon alkali activated slag based Ultra-High Performance Concrete (A-UHPC) with ultra-low moisture content. Firstly, based on the particle dense packing model, an optimized combination of low-carbon cementitious mixture and aggregates skeleton is designed. Then, the effects of moisture content on the macro-properties, hydration mechanism and micro-mechanism of the developed A-UHPC are studied. The experimental results show that the fresh performance and macroscopic mechanical properties of A-UHPC are advanced at low moisture content. When the water-binder ratio is 0.29, the compressive strength at 28 d is the highest, reaching 118 MPa. Besides, low moisture content A-UHPC also shows good microscopic properties: its hydration degree can reach 62.58% and the longest molecular chain length of the polymer is about 4.74. In general, the developed A-UHPC can meet the requirement of high performance and low CO 2 emission simultaneously, which could be one of the most suitable choices to achieve the goal of “Carbon peak and Carbon neutral” in the near future. • A novel method for designing a low carbon UHPC is presented. • The newly developed UHPC exhibits admirable ecological value. • Mineral powder and alkali-activator are adopted in UHPC. • Low moisture content A-UHPC is developed. • 5.The effect of water on the macro and micro properties of A-UHPC is studied.

Material innovation preparation and performance study of semi-flexible pavement materials

Expounding the internal stability and rutting resistance of semi-flexible materials under different porosity can predict the relationship between pavement performance and material porosity. This study designed four porosities of 18%, 20%, 22%, and 25% to prepare the base asphalt mixture. Then the cement mortar was poured into the base asphalt mixture and cured for seven days under ambient temperature and humidity conditions to prepare semi-flexible pavement material. The stress-strain level of semi-flexible pavement(SFP) was analyzed by finite element software under the 20% porosity; the rutting test was used to evaluate the anti-rutting performance of SFP under different porosity. The orthogonal experiment indicated that the optimal ratio of cement mortar was 0.6 water-cement ratio, 15% mineral powder, and 35% sand. The finite element results further showed that the internal shear stress mainly causes the internal displacement and strain of the material. The shrinkage of the cement mortar was 0.168%, and the dynamic stability of SFP with porosity of 18%, 20%, 22%, and 25% were 6058, 7325, 11,053, and 12,353, respectively. The porosity and filling of cement mortar have a positive trend with the anti-rutting performance of semi-flexible pavement materials.

Research on Micro-Mechanics Modelling of TPU-Modified Asphalt Mastic

To explore the interactions and mechanisms of Thermoplastic polyurethane (TPU)-modified asphalt with different kinds of mineral fillers, a micro-mechanical model for TPU-modified asphalt mastic was established, which considered the interaction between asphalt and mineral powder to effectively analyze the internal mechanisms affecting the rheological properties of TPU-modified asphalt mastic. In this study, according to the micro-mechanics of composites’ principles, the dynamic shear modulus (|G*|) of asphalt mastic with different mass ratios of filler/asphalt (F/A) was calculated by the homogenize morphologically representative pattern (H-MRP) model. The key ratio of F/A, which is close to the test result, can be determined, and a four-phase H-MRP model of the TPU modified asphalt mastic was established after considering the structure of asphalt layer thickness. The results were interpreted based on the known reactions of TPU with asphalt model compounds. The |G*| of TPU-modified asphalt mastic was predicted by using this model. Furthermore, the effects of the complex shear modulus, Poisson’s ratio of TPU-modified asphalt, Poisson’s ratio, particle size of mineral powder, and thickness of the structural asphalt layer in the |G*| of TPU-modified asphalt mastic were analyzed in the whole-model construction, as well as the internal mechanism of the |G*| of TPU modified asphalt mastic. In addition, can also be found the predicted value of |G*| calculated by the four-phase H-MRP model is close to the experimental value after choosing a structural asphalt layer of appropriate thickness.

Dynamic Compression Properties of Ni-Fe Slag Powder Soil Cement under Impact Load

In this research, Ni-Fe slag powder and mineral powder are blended into mineral admixtures and added to soil cement, with the aim of investigating the mechanical property of soil cement under a dynamic environment, and the dynamic properties of Ni-Fe slag powder soil cement after impact compression are obtained by conducting split-Hopkinson pressure bar (SHPB) test. The results show that under the same age and different admixture conditions, the dynamic stress of Ni-Fe slag powder soil cement increases first and then decreases and reaches the maximum when the admixture ratio is 40%, and the dynamic stresses at 7 d, 28 d and 60 d were 5.10 MPa, 9.73 MPa and 13.51 MPa, respectively. Under the same admixture ratio, Ni-Fe slag powder soil cement shows an increasing trend in dynamic stress with age, and its growth rate at the curing age from 7 d and 28 d is significantly higher than that at the curing age from 28 d to 60 d. After comparison, it is concluded that the best admixture ratio for Ni-Fe slag powder is 40%, which is close to the maximum value of 45% for mineral admixtures to replace cement as specified in the national standard.

Modification of Rubberized Concrete: A Review

One of the environmental problems causing concern in the world today is the black pollution caused by the accumulation of waste rubber resources. Relevant experimental studies have proved that rubber concrete can help solve the black pollution problem caused by waste rubber tires, but it is undeniable that rubber particles will reduce the mechanical properties of concrete. To this end, many studies on the modification of rubberized concrete have been carried out, and this paper summarizes these studies, considering compressive strength, durability performance and insulation performance. The results show that chemical pretreatments, such as sodium hydroxide, can significantly improve the adhesion between rubber particles and cement matrixes. Mineral powder admixtures, such as silica fume and fiber admixtures, e.g., PP fibers, can improve the compressive strength of rubber concrete.

Microwave-ignited DC-plasma ejection from basalt: Powder-generation and lightning-like effects

A phenomenon of dusty plasma ejected from basalt is presented, in the form of a stable, long-lived fire-pillar, solely sustained by a direct-current (DC) supply. The plasma is emitted to the air atmosphere from a molten hotspot, initially created in the basalt rock by localized microwave-heating (LMH). After an LMH-to-DC transition, the plasma column is solely sustained as a fire-pillar of ∼2 cm diameter, ∼4-cm height using a DC supply of ∼0.2 kV, ∼5 A, steadily lasting for periods longer than 3 min. The dusty-plasma products, accumulated in a powder form, consist of micro- and nanoparticles of basalt's components, including oxides of Si, Na, Fe, P, K, Mg, and Ti. The experimental conditions for the DC sustainability of basalt's dusty-plasma column are analyzed by various theoretical estimates. A possible relevance of these laboratory observations is attributed to atmospheric fire-pillar-like effects, associated, for instance, with volcanic-, ball-lighting, and lunar dusty-plasma phenomena. A potential application, utilizing this effect of DC-sustained dusty-plasma columns, is proposed for the direct extraction of mineral powders from rocks.

Effects of operational and geometrical parameters on velocity distribution and micron mineral powders classification in cyclone separators

The application of cyclone separators in the classification of micron powders can achieve satisfactory performance with low operation costs. The effects of operational and geometrical parameters including the inlet velocity, vortex finder length, and vortex finder diameter on the velocity distributions and classification performance of micron powders in cyclone separators were studied via CFD simulation and experiments. The results revealed that the inlet velocity and vortex finder diameter significantly affect velocity distribution and particles separation owing to changes in swirl intensity and axial backflow. The vortex finder length influences the positive effects of vortex finder, and a sufficient length should be chosen to weaken the disturbance of inlet airflow and enhance particles separation. The classification results of micron ground calcium carbonate powder indicated that these parameters all significantly affect the cut size and classification sharpness, and moderate values of these parameters should be selected to obtain a satisfactory classification performance.

Recycling of isabgol (Plantago ovata Forsk.) straw biomass and mineral powder with bio-inoculants as an effective soil amendment for isabgol cultivation

Efficient utilization of isabgol ( Plantgo ovata Forsk.) straw biomass through preparation of bio-active organic fertilizer in a natural composting process has not been studied. In this study, phosphate rock and silicate mineral (mica) powder were used as natural sources of phosphorus (P) and potassium (K), respectively. Cow dung slurry as a natural decomposer was mixed with the straw biomass at a 10:1 (weight/weight) ratio along with mineral powder. Then, nutrient-mobilizing bio-inoculants were used in the composting process after attaining thermal stabilization. The agronomic effectiveness of the resulting bio-active compost (BAC) as a bio-organic fertilizer was compared with that of conventional organics (farmyard manure and vermicompost) and chemical fertilizer (CF) by growing isabgol under field conditions. Composting with the natural sources of P and K along with the bio-inoculants increased the total nitrogen (13.6 g kg -1 ), P (38.7 g kg -1 ), and K (31.2 g kg -1 ) contents in the final product ( i.e ., BAC) compared with composting without the mineral powder and bio-inoculants. Application of BAC remarkably improved the seed yield (2.5%) and husk quality of isabgol in comparison with conventional organics and CF. Compared with CF, BAC significantly boosted the economic yield of isabgol by improving the husk recovery (2.5%) and mucilage yield (4.12%). Furthermore, BAC significantly improved the soil quality by increasing organic carbon (C), available nutrients, and microbial biomass C contents, as well as enzyme activity. The positive correlation between soil and plant parameters also highlighted the benefits of BAC for isabgol production through soil quality improvement. Therefore, it can be considered as a zero-waste technology, whereby a large quantity of straw biomass generated from isabgol cultivation, which contains essential nutrients, can be recycled back to the soil. Furthermore, BAC can be effectively used as a bio-active organic fertilizer, particularly in systems where chemical inputs are restricted, such as organic agriculture.

Properties of sustainable self-compacting concrete containing activated jute fiber and waste mineral powders

Self-compacting concrete (SCC) mixtures requires a large amount of Portland cement and thus resulting in high CO2 emissions, expanding its application has been in question to environment sustainability. Accordingly, environmental-friendly alternatives to Portland cement in SCC mixtures are deemed necessary for the progress of SCC in construction. In this investigation, treated jute fibers and mineral powders were used to replace cement in SCC mixtures. The effects of fibers and powder contents, fiber treatment, and mineral powder types on the workability and mechanical properties of SCC mixtures were investigated through slump-flow, compressive, and flexural tests. A microstructure was conducted through scanning electron microscopy. It was concluded that mineral powders and jute fibers could significantly improve the workability and mechanical properties of SCC. The microstructure observations demonstrated that the proposed methods are capable of enhancing the mechanical properties of SCC with an optimum fiber content. Specifically, a combination of 0.1% jute fibers and 75 μm zeolite powders were found to achieve the best mechanical properties. The relevant results supply fundamental reference and background for artificial intelligence and multi-function development for future infrastructure.

Application of Foam Glass-Ceramic Composite Thermal Insulation Material in Traditional Buildings

In order to solve the application of thermal insulation materials in traditional buildings, a foam glass-ceramic composite thermal insulation material was proposed for the application of traditional buildings. First, the preparation of the hydrated glass matrix was completed by using the colloidal chemical method with sodium water glass, boric acid, calcium bentonite, and fly ash as the main raw materials. Second, using the introduction of crystalline mineral powder fly ash and secondary heat treatment, a low-temperature foam glass-ceramic composite material with lightweight, high strength, good water resistance, and low cost is prepared. Finally, the process parameters such as dehydroxylation heat treatment temperature and holding time involved in the preparation process were explored and optimized. It is proved that the external content of fly ash is 20 wt.% and above, and the external content of boric acid is 1-2 wt.%. The mixed sol has a bulk density of 192–256 kg/m2, a compressive strength of 0.44–0.63 MPa, a weight loss rate of 5.1–7.8 wt%, and a softening coefficient of 0.85–0.95, and thermal conductivity is 0.056–0.064 W/(m·K).

Research on optimizing performance of desulfurization-gypsum-based composite cementitious materials based on response surface method

Desulfurization-gypsum-based composite cementitious materials were prepared by adding certain proportions of sulfoaluminate cement, mineral powder quick lime, retarder, and water reducer into the original desulfurization gypsum and semi-hydrated desulfurization gypsum. Based on the Box–Behnken design of the response surface methodology (RSM), regression models were established to evaluate the influences of various variables and the interactions between variables on the mechanical properties and water resistance of these composites. The significance of the fitted models was revealed by comparing the predicted results with experimental data. Additionally, the composition of the hydration products and the micromorphology of the hardened body were investigated by X-ray diffraction and scanning electron microscopy to explain the influence mechanism. The results showed that the strength and water resistance of the desulfurization-gypsum-based composite cementitious materials were affected by single factors as well as the interactions of pairs of factors. The analysis of variance and fitting precision also showed that the fitting effects of the established polynomial models were all high. The optimal contents of sulfoaluminate cement, mineral powder, and quicklime were 7.82%, 21%, and 5.22%, respectively, under which the composites exhibited excellent strengths and water resistance.

Time-Sensitive Aspects of Mars Sample Return (MSR) Science.

Time-Sensitive Aspects of Mars Sample Return (MSR) Science.

The Influence of the Different Cementitious Material on Self-Healing of Microcracks in Shotcrete

Due to a particular construction process, the shotcrete structure is affected by external load, material aging, and external temperature during use, with cracks inevitably appearing. Cracks are formed from microstate gradually, and thus controlling the development of microcracks in the early phase can effectively improve the strength and impermeability of shotcrete. In this study, the method of laboratory experiment and analysis is adopted to study the effect of ettringite on achieving the self-healing effect of shotcrete. The test results show that: (1) after encountering water, ettringite effectively plays a microexpansion effect to fill the pores, helping shotcrete achieve the effect of waterproofing and self-healing, which is very suitable for single-layer lining structures with water seepage. (2) The content of ettringite is inversely proportional to the change law of pore structure. When the content of ettringite increases, the porosity and harmful pores proportion have a significant decrease. (3) Fly ash and mineral powder with a mixing amount of about 30% will not affect the strength of the concrete, while prolonging the time of the effect of ettringite, will effectively improve the impermeability of the shotcrete.

Experimental and molecular dynamics simulation investigation on filler reinforcement for property enhancement of PU composites

The effect of filler modification on polyurethane (PU) properties was investigated by experimental and molecular dynamics simulation. Ultra-thin wearing course (PUTWC) was prepared using PU composite as a binder. The results indicated that, compared with composite with mineral powder, the tensile strength and elongation at break of PU composite (PUNC) containing CaCO3 increased by 32.7% and 15.8%, also exposed an appropriate viscosity. Stronger interaction energy and smaller free volume distribution existed in PUNC interface, which was obviously related to the PU soft segment. Additionally, prepared PUTWC using the single-layer paving method and PUNC of 1 kg. (m2)−1 showed high-skid resistance.

Rheological properties of asphalt mortar with silane coupling agent modified oil sludge pyrolysis residue

The treatment of oil sludge pyrolysis residue is a difficult problem and results in low resource utilization rate. This paper investigated the performance of oil sludge pyrolysis residue modified by silane coupling agent used to replace mineral powder in asphalt mortar. Different dosages of silane coupling agent and filler-asphalt ratios were considered, and the modification effects and mechanisms of silane coupling agent on the rheological properties of asphalt mortar with oil sludge pyrolysis residue were analyzed. Firstly, the physical and chemical properties of oil sludge pyrolysis residue were explored by electron microscopy scanning and infrared spectroscopy. Then, the rheological properties of asphalt mortar were examined by three major indexes (asphalt mortar, rheological properties of asphalt mortar, and water boiling test) to investigate the effect of different dosages of silane coupling agent on the rheological properties of asphalt mortar of oil sludge pyrolysis residue. Finally, the microscopic interfacial properties and modification mechanism of oil sludge pyrolysis residue asphalt mortar modified by silane coupling agent were analyzed by electron microscopy and infrared spectroscopy tests. The results demonstrated that, the oil sludge pyrolysis residue presented a well-developed pore structure and can form strong adsorption with asphalt; After the modification by silane coupling agent, the high-temperature performance and adhesion performance of the oil sludge pyrolysis residue asphalt mortar were significantly improved, and the low-temperature performance was significantly optimized. The asphalt mortar modified by 1.5% silane coupling agent shows the best performance. Compared with mineral powder asphalt mortar, the creep properties of the modified asphalt mortar at −6℃, −12℃ and −18℃ is reduced by 9.6%, 7.5% and 2.5%, the rutting resistance factor at 64℃, 70℃, 76℃ and 82℃ isimproved by −8.4%, 2.9%, 3.8%, and 8.0%, and the mass-loss rate after boiling is reduced by 27.3%. The silane coupling agent makes the filler surface become rough, and have an activation effect to increase its porosity, improve the adsorption properties of oil sludge pyrolysis residue on the light components in asphalt. Therefore, a strong physical and chemical adsorption forms between the filler and asphalt, and thus improve the pavement performance of the modified asphalt mortar.

Compressive strength prediction of sprayed concrete lining in tunnel engineering using hybrid machine learning techniques

Sprayed concrete lining is a commonly employed support measure in tunnel engineering, which plays an important role in construction safety. Compressive strength is a key performance indicator of sprayed concrete lining, and the traditional measuring method is time-consuming and laborious. This paper proposes various hybrid machine learning algorithms to accomplish the advanced prediction of compressive strength of sprayed concrete lining based on the mixture design. Two hundred and five sets of experimental data were collected from a water conveyance tunnel in northwestern China for model construction, and each set of data was made up of six basic input variables (i.e., water, cement, mineral powder, superplasticizer, coarse aggregate, and fine aggregate) and one output variable (i.e., compressive strength). In order to eliminate the correlation between input variables, a new composite indicator (i.e., the water-binder ratio) was introduced to achieve dimensionality reduction. After that, four hybrid models in total were built, namely BPNN-QPSO, SVR-QPSO, ELM-QPSO, and RF-QPSO, where the hyper-parameters of BPNN, SVR, ELM, and RF were auto-tuned by QPSO. Engineering application results indicated that RF-QPSO achieved the lowest mean absolute percentage error (MAPE) of 3.47% and root mean square error (RMSE) of 1.30 and the highest determination coefficient (R2) of 0.93 in the four hybrid models. Moreover, RF-QPSO had the shortest running time of 0.15 s, followed by SVR-QPSO (0.18 s), ELM-QPSO (1.19 s), and BPNN-QPSO (1.58 s). Compared with BPNN-QPSO, SVR-QPSO, and ELM-QPSO, RF-QPSO performed the most superior performance in terms of both prediction accuracy and running speed. Finally, the importance of input variables on the model performance was quantitatively evaluated, further enhancing the interpretability of RF-QPSO.