Perlite Powder Research Articles

Application of the Taguchi method to optimize the strength level of dispersed-filled polymers with reduced combustibility

The article considers optimization of strength level of dispersed-filled polymer materials based on polyurethane BASF with addition of perlite powder and aluminum hydroxide of different dispersion degree. The Taguchi experiment was chosen as a method of investigation. The experiment plan includes 7 controlled factors and 2 interference factors. An optimal combination of factors is determined to provide a maximum signal-to-noise ratio and a minimum variation coefficient. Controlled factors are ranked by degree of influence on sensitivity of tensile strength to interference. The applicability of the Taguchi method to optimize the strength of dispersed-filled polymers has been confirmed.

Thermal conductivity of evacuated expanded perlite measured with guarded-hot-plate and transient-hot-wire method at temperatures between 295 K and 1073 K

The effective thermal conductivity of two evacuated expanded perlite powders has been measured at temperatures between 295 K and 1073 K. Since conduction via the gas phase is suppressed, thermal transport occurs only via solid conduction and thermal radiation. Due to thermal contact resistances between the powder particles, solid conduction is very small and radiative heat transport dominates, especially at high temperatures. Applying the guarded-hot-plate (GHP) method to optically thick specimens, the true effective thermal conductivity λeff, which is the sum of solid thermal conductivity λs and radiative thermal conductivity λr from the diffusion model, has been measured. After plotting λeff as a function of third power of absolute temperature and calculating the regression line, λs is obtained from the intercept of the line, and the extinction coefficient for thermal radiation E is determined from its slope. The resulting values are λs = (6.4 ± 1.5) ∙ 10−3 W m−1 K−1 and E = (1600 ± 40) m−1 for the first perlite powder and λs = (3.1 ± 1.3) ∙ 10−3 W m−1 K−1 and E = (5700 ± 350) m−1 for the second. With an effective thermal conductivity below 0.01 W m−1 K−1 up to a mean sample temperature of 473 K, the second material is suitable to realize an economic evacuated powder insulation for medium-temperature applications up to approximately 673 K at the hot side. Both materials have also been investigated with the transient-hot-wire (THW) method. This technique has the advantage of shorter measurement time, but underestimates the effective thermal conductivity according to numerical calculations from literature, especially for samples with 1000 m−1≤E≤ 10 000 m−1. This leads to an apparent extinction coefficient Eapp>E from the λeff vs. T3 plot. Using the same procedure as above, the THW measurements deliver λs = (3.9 ± 2.7) ∙ 10−3 W m−1 K−1 for the first perlite powder and λs = (2.2 ± 1.4) ∙ 10−3 W m−1 K−1 for the second, which agrees with the values obtained from the GHP method. The apparent extinction coefficients are Eapp = (2170 ± 110) m−1 and Eapp = (6730 ± 370) m−1, which corresponds to an overestimation by 35.6% and 18.1%, respectively. Both results are in good agreement with the numerical calculations from literature, which have now been verified experimentally for the first time. Because such calculations can in principle be used to correct experimental THW data, it is possible to extend the applicability of the THW method to materials with 1000 m−1≤E≤ 10 000 m−1, i.e. near the limit of radiation diffusion.

Durability of self-consolidating concrete containing natural waste perlite powders

Perlite is a natural glassy volcanic rock used in construction applications requiring improved lightweight, thermal, and acoustic properties. During processing of raw perlite (i.e., cutting and fractioning to different sizes), large amounts of powders are collected and stored as waste materials. This paper evaluates the effect of waste perlite (WP) powders on durability and long-term transport properties of self-consolidating concrete (SCC). Different mixtures prepared with 580 kg/m3 powder using various combinations of WP, limestone filler (LF), metakaolin (MK), and silica fume (SF) are tested over 2-years period. Test results showed that WP confers particular benefits to the SCC compressive strength and its evolution over time, particularly when used in combination with MK and SF. Water permeability, carbonation, and chloride ion migration curtailed when WP concentration reached 220 and 260 kg/m3. In contrast, the resistance against freeze/thaw remarkably improved, given the pozzolanic reactions and porous nature of such powders that accommodated the disruptive expansive stresses resulting from frost attack.

Performance of Self-Compacting High-Performance Concrete Produced with Waste Materials after Exposure to Elevated Temperature

Incorporating waste and recycled materials in concrete has not just a sustainable benefit, but also gives a higher resistance to special circumstances that face concrete structures, such as fire, which causes serious damages to concrete. The present study experimentally investigated the impact of incorporating recycled coarse aggregate (RCA) and two unprocessed waste powder materials on the residual mechanical properties of self-compacting high-performance concrete (SCHPC) after exposure to elevated temperature. Fifteen mixtures of SCHPC (540 specimens) have been produced by replacing the cement mass by up to 30% of each waste fly ash (WFA) and waste perlite powder (WPP) in addition to replacing the coarse natural aggregate (NA) by up to 50% of RCA. Using RCA up to 50% enhanced the residual mechanical properties of SCHPC after exposure to the elevated temperature due to the strong aggregate–mortar contact zone and the similarity of thermal expansion between them. The fire resistance of SCHPC has been enhanced by replacing the cement up to 15% of WPP; meanwhile, WFA did not affect the fire resistance of SCHPC significantly.

A Novel Strengthening Method for Damaged Pipeline under High Temperature Using Inorganic Insulation Material and Carbon Fiber Reinforced Plastic Composite Material.

In this paper, a strengthening method for the damaged high-temperature steel pipeline using inorganic insulation material which was confined by carbon fiber reinforcement plastic (CFRP) composite materials was proposed. Two inorganic insulation materials were composed of magnesium phosphate cement (MPC) mixing with perlite and vermiculite powders, respectively. The influences of insulation material composites with various ratios of the perlite or vermiculite powder were discussed, in terms of compressive strength and thermal conductivity coefficients of inorganic insulation materials. The insulation materials confined by carbon fiber reinforced polymer jackets for enhancing the mechanical behavior were also investigated. From the experimental results, the main finding of the work was that the inorganic insulation materials added to the perlite powder represented greater insulation capability than added vermiculite ones under the condition of the same compressive strength. Different ratios of perlite inorganic insulation material cylinders with the dimension of ϕ 10 cm × 20 cm were confined by one layer and two layers of CFRP composite material. The compressive strength of the specimens increased by 258%–927% after using 1-layer CFRP composite material and increased by 480%–1541% after applying 2-layer CFRP composite material. A peak strength prediction model of insulation materials confined by CFRP was proposed, and it was found that the proposed model accurately predicted the peak strength of the inorganic insulation material cylinder. Finally, a verification test of the strengthening method for damaged high-temperature pipeline was performed to prove that the proposed strengthening method is feasible.

An insight into temperature characteristics of ternary blended concrete with perlite powder

The present study aims at experimentally investigating the applicability of Ternary Blended Concrete (TBC) with Perlite Powder (PP) and Silica Fume (SF) as a partial replacement material which would offer resistance to elevated temperatures. In this direction, keeping the content of SF constant at 10%, four different TBC mixes were prepared by varying the content of PP from 1 to 7% with an increment of 2%, in addition to control concrete. The specimens, after being properly cured, were subjected to elevated temperatures in the range of 200–800 °C in steps of 200 °C, followed by air-drying. Experimental procedures like compression test, TGA-DTA, and XRD analysis were carried out. The results of these analyses show that TBC mix with 5% replacement of PP at 400 °C exhibited the highest strength and better thermal properties. An increased residual strength of about 30% was observed at 800 °C. Thermal analysis shows weight losses of 9.677%, 7.530%, and 1.596%, respectively, in the three phases of 5% PP is more, which is due to the presence of high pores. It is recommended that TBC with 5% PP and 10% SF be used as a good composite material with resistance to high temperatures.

Effect of perlite powder and silica fume on the compressive strength and microstructural characterization of self-compacting concrete with lime-cement binder

This study evaluated the short and long term mechanical properties of self-compacting concrete (SCC) with a lime-cement binder, silica fume (SF), perlite powder (PP), and silica fume-perlite powder mixture (SF-PP) as additives. The aim of the present study was to investigate the effects of different amounts of additives on the fresh and mechanical properties of SCC. Also in this research cement-lime binder was replaced by SF, PP, and SF-PP at 0%, 5%, 10% 15%, and 20%, respectively. The optimum percentage was 17% for SF, 6% for PP and 6% for SF-PP on 28th and 90th days to obtain maximum compressive strength. The results showed that water absorption, dry density, of the 28-days compressive strength increased with an increase in silica fume (SF) content. The contents of PP and SF-PP replacement also influenced the resulting SCC, but the latter had a better effect on the concrete. The highest compressive strength of SCC was observed at 17%, 6%, and 6% for SF, PP and SF-PP, respectively (on days 90). When 10% lime powder was added instead of cement, the optimum usage of SF dropped to below 20%. The optimum usage of SF for normal concrete is above 20%.

The impact of time on the heat resistance of self-compacting high-performance concrete incorporated with recycled martials

The influence of time on the mechanical behavior of concrete after exposure to elevated temperatures has been studied. Twenty-one self-compacting high-performance concrete mixtures with different incorporation amounts of coarse recycled concrete aggregate (RCA) and three unprocessed waste powder materials have been tested at age of 270 days for residual compressive and flexural strength after exposure to fire. The results have been compared to the results for the same concrete, which have been studied at age of 90 days. A new parameter has been introduced for comparing the responses of concrete to elevated temperatures at different ages; this parameter was the “heat resistance” which expresses the total area under the curve of the relative residual strength (compressive or flexural) after exposing to six temperature degrees (20, 150, 300, 500, 600, and 800 °C). The results showed that the age of concrete has an influence on the response of concrete to elevated temperatures. The heat resistance of compressive strength enhanced with age but the concrete behaved with a tendency different to that at the age of 90 days. The heat resistance of flexural strength has not been affected or slightly decreased but not with more than 10% to that at the age of 90 days. The used waste powder materials were unprocessed waste fly ash, waste cellular concrete powder and waste perlite powder; they proved that using any of them up to 15% as a replacement for cement with 0% or 25% of RCA enhanced the concrete resistance for the fire with time. The main two reasons for changing of residual strength with the time were the changing of water content and the proceeding of hydration of the binder. In general, long ages testing properties of concrete simulate the real behavior of concrete structures accurately.

Long-term durability of self-compacting high-performance concrete produced with waste materials

Abstract Durability tests for twenty-one self-compacting high-performance concrete (SCHPC) mixtures have been conducted to investigate the impact of using coarse recycled concrete aggregate (RCA) and three other unprocessed waste powder materials: unprocessed waste fly ash (UWFA), waste perlite powder (WPP) and waste cellular concrete powder (WCCP). Chloride migration, water penetration and absorption, freeze/thaw resistance have been investigated at different ages up to 270 days and the results showed that using RCA has no significant effect on the durability properties of SCHPC when used up to 50%. Concretes produced using UWFA or WPP as a replacement of cement mass up to 15% showed excellent durability performance regardless if the coarse aggregate used was natural aggregate (NA) or RCA. SCHPC proved it can be produced as a green concrete, where the pozzolanic activity and the amorphous waste powder materials help the concrete resist aggressive environments. Using WCCP is not recommended for the purpose of enhancing the durability of SCHPC, as well as excessive replacement amounts of either WPP or UWFA. In general, the effects of both WPP and UWFA on durability properties became more significant due to the hydration proceeding with age.

Improving the hardened and transport properties of perlite incorporated mixture through different solutions: Surface area increase, nanosilica incorporation or both

Abstract This study investigates the effect of the synergetic incorporation of perlite powder and nanosilica (NS) on mechanical and transport properties of mortar. Inherently, perlite possesses a slow pozzolanic activity, which can prolong the improvement in mechanical and transport properties of concrete. As such, in this study, perlite powder was ground to fine particles with the specific surface area (SSA) of 3100 cm2/g and 3900 cm2/g and was added to the mixture with 10% and 15% replacement level, respectively. Moreover, NS, which is found to accelerate the pozzolanic reaction in cement matrix due to the high surface area, with dosage of 1%, 2%, 3%, and 4% was added to the mixtures in conjunction with the ground perlite to further overcome the slow reactivity of perlite at early ages and improve mechanical and transport properties. The compressive strength of the samples was assessed, and it was found that 15% replacement of Ordinary Portland Cement (OPC) with perlite, with the SSA of 3900 cm2/g, and 2% NS led to the highest compressive strength of 68.3 MPa. Transport properties such as electrical resistivity, rapid chloride migration, and capillary water absorption of the samples were assessed. It was observed that the mixture with 2% NS and 15% replacement of OPC with perlite could increase the electrical resistivity to 35.2 kΩ·cm and reduce the migration coefficient to 4.1*10−12 m2/s at 91 days. Moreover, this mixture decreased the water absorption at 28 days to the extent of 43% in comparison with the control mixture.

Behavior of perlite-based mortars on physicochemical characteristics, mechanical and carbonation: Case of perlite of Hammam Boughrara

This manuscript is based on the study of pozzolanic activity of the perlite powder (PP) of Hammam Boughrara by the consumption of lime and the hydration of paste made with 75% of PP and 25% of lime. The fresh properties of the cement pastes were defined by normal consistencies, initial and final setting time and autoclave expansions. The manufactures of mortars for flexural and compressive strength, absorption, porosity and carbonation tests were evaluated. Four combinations with a rate of 0%, 10%, 20% and 30% substitution of cement with PP are used in order to compare them with cement without addition. The results showed that the reaction between the lime, silica and alumina of PP gives rise to several hydrates such as calcium silicate hydrate, hydrated calcium aluminates and hydrated gelhenite. This confirms the pozzolanicity of this PP. A substitution rate of PP between 10% and 20%, will increase the mechanical performance over time, densify the transfer matrices of mortars and ensure good resistance to carbonation.

The effect of natural pozzolans on properties of vibropressed interlocking concrete blocks in different curing conditions

Abstract Concrete block pavements have become an attractive engineering and economical alternative to both flexible and rigid pavements because of it’s high strength and durability. The influence of pozzolanic mineral additions – natural zeolite and expanded perlite powder on the properties of concrete interlocking blocks in different curing conditions has been studied. The use of zeolite as a substitute for cement in the production of concrete blocks increased the water demand but decreased the water absorption of the blocks. Obtained results show, that concrete blocks with 10% substitution of cement with zeolitic tuff is characterized by higher strength, lower mass loss and absence of efflorescence.

Properties of lightweight concrete made with core-shell structured lightweight aggregate

In this study, core-shell structured lightweight aggregates (CSA) were produced through the cold bonding method, by encapsulating an expanded perlite particle (as a core structure) within a shell matrix composed of cement, fly ash and expanded perlite powder. The effect of different curing regimes on the mechanical and microstructural properties of the CSA were studied. To enhance the characteristics of the aggregates produced, they were surface treated by a mixture of cement and silica fume, using two different treatment methods. Afterwards, the properties of lightweight concrete made of either CSA or expanded clay aggregate (ECA) were compared closely in terms of their potential economic and environmental benefits, in response to the high energy consumption associated with the production of ECA. The results revealed that curing at a relative humidity of 99% is the most appropriate curing method for CSA. In addition, treating the CSA surface contributes significantly to enhancing its bulk crushing strength, by about 14–18%. The findings also demonstrate the feasibility of using CSA to produce lightweight aggregate concrete, with a dry density and compressive strength ranging from 1115 to 1540 kg/m3 and from 17.9 to 25.8 MPa, respectively, with a corresponding thermal conductivity range of 0.3169–0.6660 W/m·K.

Mechanical Properties of Recycled Aggregate Self-Compacting High Strength Concrete Utilizing Waste Fly Ash, Cellular Concrete and Perlite Powders

The sustainability of engineering products has become a basic requirement instead of a mere choice because the harmony between economic activity and the earth’s ecosystem must be seriously considered. The influence of using three unprocessed waste powder materials as cement replacing materials (CRMs) and/or coarse recycled concrete aggregate (RCA) as a partial replacement of coarse natural aggregate (NA) on fresh and mechanical properties of self-compacting high-strength concrete (SCHSC) is investigated in this study. The activation index of the CRMs on the cement paste is tested as an initial step. The CRMs, namely, waste fly ash (WFA), waste perlite powder (WPP) and waste cellular concrete (WCC), are tested through 21 mixtures allocated by seven different series with three mixes of each. The mechanical properties of the 21 concrete mixes are determined after one, three and nine months of curing. Results of compressive strength, splitting tensile strength, flexural strength and modulus of elasticity are presented. This work shows that the mechanical and environmental performance of SCHSC can be improved by the replacement of NA by RCA of up to 50% and the replacement of cement by WPP or WFA of up to 15%. Using WCC is not recommended to be reached 15% and using WFA is preferable to be with incorporating RCA rather than NA alone. Findings indicate that incorporating waste materials can be valuable in SCHSC, thereby potentially leading to an increasingly green environment and paving the way for advancements in sustainable construction.

Proposal for Cryogenic Deburring Equipment’s Design and Thermal Insulation

In the paper are presented elements of the deburring technology of rubber or plastic parts in cryogenic conditions. There is a proposal for deburring equipment that follows: simplicity in use, increased production capacity and reduced consumption of liquid nitrogen. The heat transfer through the insulating layer is calculated using several types of thermal insulation: perlite powder, spray-on polyurethane foam and aerogel blanket. The obtained results are used for the design of a cryogenic deburring equipment where the thermal transfer is minimal.

Study on thermal insulation of liquefied natural gas cryogenic road tanker

The tanks designed for liquefied natural gas transport must be thermally insulated from the environment due to the low condensing temperature of the gas. The effectiveness of thermal insulation significantly affects the tank's operating parameters and its operating costs. As there is no perfect insulation, there is a need for analyses that would determine its suitability in specific applications. In this paper the issue of heat transfer through double-walled cryogenic tanks with evacuated insulation system was discussed. Afterwards the study of insulation variants of liquefied natural gas cryogenic road tanker was presented. The use of several layers of insulation made of modern and efficient materials such as aero-gel and fiberglass or the use of multi-layer isolation has been considered and compared to the use of perlite powder. The heat flux through insulation systems was tested for different variants of evacuated insulation under residual gas pressure of 10-1 Pa, 10-3 Pa, and 100 kPa. Finally, for selected insulation variants, the heat leakage was tested for 50 m3 liquefied natural gas road tanker. The investigation of heat-flow for the transient thermal analysis was performed by applying finite element method. The aim of the study was to determine the variant of insulation system with the relatively low heat leakage to the tank and low cost of materials and vacuum production.

Pretreatment of natural perlite powder by further milling to use as a supplementary cementitious material

Replacing a portion of ordinary Portland cement (OPC) with natural pozzolans may be an effective solution to reduce the carbon footprint of the concrete industry and construction costs, and to improve concrete durability in general terms. However, some natural pozzolans, such as perlite, need to be pretreated to be reactive enough and satisfy the minimum standard qualifications of the concrete industry. This research investigated the effectiveness of milling of natural perlite as an alternative to calcination, which is the more common reactivation method. For this purpose, the effects of replacing OPC with natural perlite powder (NPP) were studied at three different levels of fineness and replacement ratios. A variety of tests for the mechanical and transport properties of the concrete were carried out, including a compressive strength test, a surface electrical resistivity test, a water penetration test, a rapid chloride permeability test, and a rapid chloride migration test. These tests conducted on 14 different types of concrete mixtures with various ratios of water-to-cementitious materials (W/Cm), cement content, and replacement ratios. The results demonstrated that increasing the fineness of natural perlite could be an effective method to reactivate NPP, leading to almost the same compressive strength while improving the transport properties significantly.

Effects of the mechanical milling method on transport properties of self-compacting concrete containing perlite powder as a supplementary cementitious material

The purpose of this study is to measure the effects of increasing the specific surface area of perlite natural pozzolan in self-compacting concrete (SCC) by the mechanical milling method. The use of SCC in construction projects allows for a reduction of human resources and equipment, which significantly decreases the labor cost and time of construction. SCC often needs chemical additives to achieve workability requirements. However, the usage of a greater amount of chemical additives as well as cement materials in the mixing designs increases the cost of mixing. Incorporation of inexpensive natural pozzolans as an alternative to cementitious materials can improve the fresh properties and durability of concrete. Moreover, reducing the hydration heat and controlling the shrinkage of SCC mixtures, which mainly contain significant amounts of powdered materials, is another benefit of the natural pozzolans. However, the reactivity of natural pozzolans, specifically in the early ages, is always a concern when using these supplementary materials. In this study, several methods have been proposed to improve the reactivity of these materials. Increasing the specific surface area of pozzolanic materials by mechanical milling is one of the most economical and efficient methods implemented so far. This study measured the performance of various levels of perlite powder, a natural pozzolan, for fresh, mechanical and durability properties. In addition, the effects of increasing the specific surface area of perlite powder on properties of concrete were measured and evaluated. According to the results, an increase in the specific surface of perlite powder improved the compressive strength and durability index as a result of increased reactivity. This was accompanied by a substantial improvement in the properties of SCC mixtures in the workability and stability tests.

Mechanical, thermal, and viscoelastic investigations on expanded perlite–filled high-density polyethylene composite

Perlite is a glassy amorphous volcanic rock and generally used in construction industries. Possible uses of perlite powder in polymeric composites allow producing value-added products. In this study, expanded Turkish perlite (TP) powder was characterized by particle size distribution and Brunauer–Emmett–Teller analysis. TP-filled high-density polyethylene (HDPE) composites were manufactured via thermokinetic mixer by adding various weight fractions of TP powder (5, 10, 20, and 30 wt%) into HDPE matrix. Produced composites were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, dynamic mechanic analysis, X-ray diffraction, and mechanical and thermal conductivity tests. From mechanical tests, it was observed that HDPE + 5% TP exhibited the greatest tensile strength. Flexural strength of the TP-filled HDPE composite was increased with the increasing TP content. Morphological properties of TP-filled HFPE composites were examined by scanning electron microscopy. As the weight fraction of TP was increased, storage modulus and loss modulus of the composites were increased. Moreover, the relaxation peak of HDPE was increased by the incorporation of TP into HDPE.

Influence of vacuum level on insulation thermal performance for LNG cryogenic road tankers

In this paper, thermal properties of materials for evacuated insulation systems of double-walled cryogenic tanks were discussed. Than the comparison of insulation variants for LNG cryogenic road tankers was presented. The use of several layers of insulation made of materials such as aerogel and fiberglass or the use of multilayer isolation (MLI) has been compared to the use of perlite powder. The average heat flux through the tank walls and insulation system has been compared under different vacuum levels and in the absence of vacuum. The comparative analysis was performed by applying transient thermal analysis using finite element method.