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Produzione di materiali per l'edilizia contenenti alcune tipologie di rifiuti industriali civili
No full textMechanical properties and microstructure of fast fired tiles made with blends of kaolin and olivine powders
No full textThe paper reports on some experimental results obtained from the production of ceramic tiles containing olivine and kaolin powders mixed in different proportions. Blending of components was done by attrition milling. Pressed powders were fast fired (55 min cold to cold) in air up to
1250 1C. Fired products were characterized by shrinkage, water absorption, density, strength, hardness, toughness, crystal phases and
microstructure. It has been demonstrated that all the samples prepared have properties in line with the industrial production of some ceramic
materials, but those containing 60 wt% of olivine and 40 wt% of kaolin displayed the best overall behaviour and therefore the blend is a possible candidate of an eventual industrial production of tile
Recycling Glass Cullet from Waste CRTs for the Production of High Strength Mortars
Full text linkhe present paper reports on the results of some experiments dealing with the recycling of mixed cathode ray tube (CRT) glass waste in the production of high-strength mortars. Waste CRT glass cullet was previously milled, and sieved, and the only fine fraction was added to the fresh mortar in order to replace part of the natural aggregate. The addition of superplasticizer was alsoinvestigated. All hydrated materials displayed high compressive strength after curing. Samples containing CRT mixed glass showed a more rapid increase of strength with respect to the reference compositions, and materials with a superplasticizer content of 1% showed the best overall performance due to the favourable influence of the small glass particles which increase the amount of silicate
hydrated produced. The induced coupled plasma (ICP) analysis made on the solutions, obtained from the leaching tests, confirmed the low elution of hazardous elements from the monolithic materials produced and consequently their possible environmental compatibility
Long term compression strength of mortars produced using coarse steel slag as aggregate
Full text linkThe paper reports on some experimental results obtained from the production of mortars prepared using a commercial cement, coarse steelmaking slag, superplasticizer and water. The behaviour of this reference composition was compared to that of some others containing further additives in order to investigate materials compressive strength after long time ageing. It has been demonstrated that an optimized water/cement ratio coupled with slag particles of size lower than 2.5 mm and proper protocol of preparation leads to the production of materials with good mechanical properties after 28, 90 and 180 days of ageing. The resulting materials therefore appeared as good candidates for civil engineering applications. However, the present research also demonstrates that the mortar samples of all of the compositions prepared suffer of decay and compressive strength decrease after long time ageing in water. In the present paper the results are explained taking account of materials residual porosity and alkali silica reaction which occurs in the sample
Recycling of steel slag and glass cullet from energy saving lamps by Fast firing production of ceramics
No full textThe paper reports on some experimental results obtained from the production of ceramics containing steel slag and glass cullet from exhaust energy saving lamps mixed in different proportions. Blending of components was done by attrition milling. Pressed powders were fast fired (50 min, cold to cold) in air up to several temperatures in the range 1000-1140 °C. The sintering behaviour was studied by shrinkage and water absorption measurements. Density, strength and hardness of the fired bodies were determined and XRD were examined. The fired samples were finally tested in acidic environment in order to evaluate their elution behaviour and consequently their possible environmental compatibility. It is observed that the composition containing 60 wt.% of steel slag and 40 wt.% of glass cullet displayed the best overall behaviour
Effects of milling on coprecipitated 3Y-PSZ powders
No full textThe present research compares properties and behaviour of co-precipitated 3Y-PSZ powders submitted, after co-precipitation, to different milling
treatments. The characteristics of the different products were evaluated by measurement of particle size distribution, thermogravimetric analysis,
X-ray diffraction, specific surface area and scanning electron microscopy analysis. It has been demonstrated that 1 h of attrition milling enables the
production of powders containing soft agglomerates of nanometric particles: the dispersing liquid used on milling has little influence. Crystallisation
into a cryptocrystalline structure of the amorphous powder is achieved after 1 h of high energetic milling, avoiding thermal treatments
Steel scale waste as component in mortars production: An experimental study
Full text linkThe present research reports on the results of some experiments dealing with the recycling of steel scale waste in the production of mortars. Materials were prepared mixing a commercial CEMII/B-LL cement, a steel scale waste, a commercial natural aggregate, superplasticizer and water. Natural aggregate was replaced with different proportions (5, 10, 20, 30 and 40% wt) of steel scale waste. Water absorption, apparent density, compression strength and thermal conductivity were measured after 28 days of curing. After curing, all hydrated materials displayed: good compressive strength and low water absorption; increased apparent density with steel scale addition; improvement of thermal conductivity in materials containing up to 10 wt% steel scale addition
High energy ball milling of titania and titania–ceria powder mixtures
No full textTitania alone and several titania-ceria blends of powders were milled by high energy ball milling for different periods of time. Phases, crystal size, particles size and morphology were evaluated. The research has demonstrated that milling reduces the mean crystallite size to less than 30 nm for any time whereas powder particles coalesce into coarse agglomerates. At the same time anatase titania transforms to rutile after 3 hours milling, but a thermal treatment at 700 °C for 1 h partially recovers the original crystal structure. The behaviour of ceria-titania blends is similar to that of titania alone, but the reversibility of the anatase–rutile transformation does not occur when the quantity of ceria is greater than a critical level which we have set between the composition with Ce/Ce+Ti ratios of 5 and 10 wt%
Possible use of waste olivine powders from a foundry process into the ceramic industry: Sintering behaviour of olivine, kaolin and their blends
No full textSteelmaking slag as aggregate for mortars: Effects of particle dimension on compression strength
No full textThe present paper reports on the results of some experiments obtained from the production, hydration and subsequent measurement of the mechanical properties of several mortars prepared using a commercial CII/B-LL Portland cement, steelmaking slag, superplasticizer and water. Relevant parameters for the mortar preparation are the weight ratios of cement/water, the weight ratio superplasticizer/cement and between fine and granulated coarse particles. It has been demonstrated that optimisation of such parameters leads to the production of materials with mechanical properties suitable for civil engineering applications. Moreover, materials with improved compressive strength can be prepared by the use of slag containing extensive amounts of large particles
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