Fine Limestone Research Articles

INFLUENCES OF CALCIUM LEVELS WITH LIMESTONE PARTICLE SIZE ON LAYING PERFORMANCE , AND EGGSHELL QUALITY TRAITS OF LAYERS

The current study estimated the influences of nutritive calcium levels besides limestone particle size upon performance , egg production and egg quality in first-cycle of Golden Montazah layers. Experimental scheme was completely randomized in 3x4 factorial arranging (three Ca levels – 2.8, 3.0 or 3.2%, in addition four particle size distributions – (100% , 50% fine plus 50% coarse , 25% F and 75% C, or 100% ) Totalizing 12 treatments including three replicates with eight birds each. Limestone size was ranged from fine (F >0.6 mm) to coarse ( 1.9 <.C < 2.8 mm). There was a significant influence of dietary calcium levels with particle sizes or the interaction between the two influences on feed intake (g/hen/day ), egg production % , calcium intake and feed conversion. Particles of limestone were significant effect on eggshell quality including density , shell breaking strength, thickness, eggshell (%) as well as EWSA . Eggshell breaking strength was enhanced when replacing fine limestone by 75% and 100% of coarser limestone substitutions . Shell thickness was significantly higher in 3 or 3.2% Ca groups compared with 2.8% Ca group. The main effect of Limestone particles size generally improved egg shell quality with increasing coarsity inclusion level. Limestone particle size significantly affected internal egg quality traits. Regardless of calcium levels , while limestone particle size is consider , best performance results of egg production, eggshell quality plus some of internal egg quality were obtained by replacing fine limestone by 75% and 100% of coarser limestone particle size . In conclusion, the addition of calcium at level (3.0 - 3.2%) with supplying of coarse limestone (1.9mm< C <2.8mm) by 75 - 100% improves the performance of laying hen

The Effect of Gradation and Grain-Size Properties of Fine Aggregate on the Building Mortars

Abstract This work is about the effect of fine aggregate properties on the physicomechanical characteristics of hardened mortars. The results indicated that the increase in grain-size of fine aggregate increases the bulk density of hardened mortars. The strength of mortars including limestone fine aggregate is higher than that of the silica-sand. Regardless of the aggregate origin, the strength of the mortars with well-graded fine aggregate for all grain-size is greater than of with uniform fine aggregate. This indicates that grading of fine aggregate increases the strength, while uniformity decreases it. The strength of mortars with well-graded fine aggregate increases as the grain-size increases. Regardless of the aggregate origin, the strength of mortars with uniform fine aggregate increases with increasing grain-size until the grain-size range of 425-1000 µm, but after this range it decreases with increasing grain-size. The thermal conductivity increases with the increase in the grain-size. Notedly, the relationship between thermal conductivity and maximum grain-size of well-graded fine aggregate has a very strong positive correlation. Further, the thermal conductivity value for mortars formed with uniform fine limestone aggregate is minimum at the grain-size range of 425-1000 µm, while it has greatest values close together from this grain-size range

Calcination thermokinetics of three Brazilian limestones

Abstract Limestone and lime producers inadvertently generate a considerable amount of fine material during their processing, consequently becoming a great environmental liability. As far as the industrial calcination process is concerned, there is still a need for an experimental survey on Arrhenius law parameters, as apparent frequency factor and activation energy, referring to Brazilian limestones. The knowledge of these thermokinetic parameters may contribute to energy saving during the industrial calcination process, as well as for allowing the use of limestone fines in other industrial applications. This study aimed to characterize three Brazilian limestones by focusing on their laboratory-scale calcination using both quasi-isothermal and non-isothermal methods to estimate their kinetic parameters. The non-isothermal method (by thermogravimetric analyses) allowed estimating the activation energy for each limestone through the high calcination rate ranges. However, the kinetic parameters estimated by the quasi-isothermal method turned out in lower values, indicating the need to control the reactor atmosphere.

Circular concrete filled steel tubes made of eco-concrete with limestone fines added as cementitious paste replacement

One effective method of reducing the cement content and carbon footprint so as to produce eco-concrete is to add limestone fines to replace an equal volume of cementitious paste. This method is herein applied to the concrete infill of concrete filled steel tubes (CFSTs). To study the properties of the eco-concrete so produced and the effects of using such eco-concrete on the axial performance of CFSTs, circular steel tubes infilled with such eco-concrete or conventional concrete had been tested under axial compression. The steel tubes were of grade S355 and had diameters ranging from 88.9 to 168.3 mm, whereas the concrete infills had water/cement ratio of 0.35–0.55, and limestone fines content by concrete volume of 8%. The results revealed that at same water/cement ratio, the eco-concrete generally had higher compressive strength and the CFSTs infilled with the eco-concrete had better axial performance. However, at same concrete strength level, the CFSTs infilled with the eco-concrete had similar axial performance. Lastly, the test results were compared with predictions by the existing design equations in various codes and it was found that the existing design equations may also be applied to CFSTs infilled with such eco-concrete.

Fine limestone dust from ornamental stone factories: a potential filler in the production of High-Performance Hybrid Fiber-Reinforced Concrete

The utilization of alternative supplementary cementitious materials (ASCM) and additives in concrete becomes a daily practice due to the increased awareness of their socio-ecological impacts. Exploring for renewable resources of ASCM has been the driving force for the research on this topic since decades. Waste materials have been shown to possess intrinsic physico-chemical properties dependent on their chemical source and physical status. However, wastes evolved in the form of fine dust are known to cause chemical, biological and visual pollution when left in open areas without collection and proper recycling or damping. The ornamental stone factories, necessary for the decoration of the contemporary constructions, produce fine limestone dust (FLSD), which was elucidated as an example in this study. A huge amount of FLSD is released from this industry. The incorporation of a high volume of FLSD and hybrid combination of steel fibers and polyvinyl alcohol (PVA) microfibers in the production of high-performance concrete (HPC) was the main objective of the study. The replacement level of 45% FLSD has enabled a high dispersion of 0.35% PVA microfibers in the presence of 1% steel fibers of the total mix volume. Moreover, the presence of FLSD has also mitigated the occurrence of PVA balling effect, which often takes place at much lower dosages. The results of the mechanical and chloride-ion penetration resistance of the final concrete mixture were encouraging. Both high compressive strength of 70 MPa and elevated modulus of rupture of 12 MPa with a cementitious matrix of very low penetration for chloride ions, supported with enhanced microstructure, could be obtained. The production of high-performance hybrid fiber-reinforced concrete containing high volume ornamental stone dust is proved feasible, ecofriendly and sustainable.

Coarse limestone does not alleviate the negative effect of a low Ca/P ratio diet on characteristics of tibia strength and growth performance in broilers

The hypothesis was tested that an increased digestion of coarse compared with fine limestone can alleviate the negative effects of a low dietary Ca/P ratio on the growth performance and characteristics of tibia strength (CTS) in broilers. A total of 1,152 Ross 308 broiler chickens received a standard commercial starter feed from day 0 to 13. From day 14 onward, birds received 1 of 12 diets containing 1 of 6 Ca/P ratios (0.50, 0.75, 1.00, 1.25, 1.50, and 1.75) and 1 of 2 limestone particle sizes (<500 [fine] and 500 to 2,000 [coarse] μm) in a study with a 6 × 2 factorial arrangement of treatments. Total P content was fixed at 5.5 g/kg for all treatment diets. Each treatment was replicated 6 times with 16 birds per replicate pen. On day 20 and 21, twelve birds per pen were randomly selected from 4 of the 6 replicate pens for tibia analysis and digesta collection from different gut segments. The apparent Ca digestibility was higher for fine than coarse limestone in the jejunum (P = 0.043). However, this difference in Ca digestibility disappeared for the low, whereas it remained for the high Ca/P ratios in the proximal (Pinteraction = 0.067) and distal (Pinteraction = 0.052) ileum. In addition, coarse limestone improved apparent P digestibility in the proximal and distal ileum (P < 0.001) but not in the jejunum (P = 0.305). Regardless of limestone particle size, reducing dietary Ca/P ratio linearly improved apparent Ca and P digestibility in the proximal and distal ileum (P < 0.001). Moreover, decreasing dietary Ca/P ratio linearly (P < 0.001) and quadratically (P < 0.046) reduced the CTS. Reducing dietary Ca/P ratio linearly (P < 0.003) and quadratically (P ≤ 0.006) decreased body weight gain and increased feed conversion ratio. For both fine and coarse limestone, the optimal Ca/P ratio was 1.00 to 1.25 to optimize apparent Ca and P digestibility while maintaining growth performance and CTS. Reducing Ca/P ratio from 1.75 to 1.00 improved distal ileal Ca and P apparent digestibility from 36.6 to 53.7% and 48.0 to 58.3%, respectively. In conclusion, coarse limestone is equally digestible with fine limestone at a low Ca/P ratio but is less digestible at a high Ca/P ratio, and the optimal Ca/P ratio in the diet is 1.00 to 1.25 for both fine and coarse limestone.

Early hydration of cementitious systems accelerated by aluminium sulphate: Effect of fine limestone

The early hydration of cementitious systems accelerated by an alkali-free aluminium sulphate based product was investigated in the presence and absence of fine limestone. The results show that the first seconds after the accelerator is added to the wet mix play a key role: Simultaneously to the massive ettringite formation, the Al2(SO4)3 accelerator favours the dissolution of the major cement clinker phase alite and thereby leads to an oversaturation of the pore solution with respect to calcium-aluminium-silicate-hydrates (C-A-S-H) and consequently the precipitation of nuclei of these phases. The surface of the limestone powder acts as an ideal substrate for these nuclei, which are the foundation for an outstanding early-strength-giving effect a few hours later.

Effect of Sugarcane Bagasse Ash and Lime Stone Fines on the Mechanical Properties of Concrete

Cement production releases huge amounts of carbon dioxide having a significant impact on the environment while also having huge energy consumption demands. In addition, the disposal and recovery of natural concrete components can lead to environmental degradation. The use of waste in concrete not only reduces cement production, but it also reduces energy consumption. The aim of this study is to evaluate the properties of fresh and hardened concrete by partially replacing cement with sugarcane bagasse ash (SCBA) and limestone fines (LSF). In this investigation work the cement was replaced with SCBA ash and LSF by 0% (0% SCBA+ 0% LSF), 5% (2.5% SCBA+ 2.5% LSF), 10% (5% SCBA+ 5% LSF), 15% (7.5% SCBA+ 7.5% LSF) and 20% (10% SCBA+ 10% LSF) by weight of cement. In this regard, a total of 60 samples of concrete specimens were made with mix proportion of 1:1.5:3 with 0.56 water-cement ratio. Cube specimens were tested for compressive strength and cylindrical specimens were used for determining splitting tensile strength at 7 and 28 days respectively. The optimum result displayed that the crushing strength and split tensile strength increased by 10.33% and 10.10% while using 5% SCBA+ 5% LSF as a substitute for cement in concrete after the 28th day. The slump value of concrete declined as the content of SCBA and LSF increased.

Effect of Sugarcane Bagasse Ash and Lime Stone Fines on the Mechanical Properties of Concrete

Effect of Sugarcane Bagasse Ash and Lime Stone Fines on the Mechanical Properties of Concrete

Characterization of the sulfation reactivity of limestones with different particle size in a large-capacity TGA

Limestone particle size has a significant influence on the desulfurization effect in CFB boilers. However, few studies have focused on the effects of particle sizes under different conditions. As a result, many existing sulfation models have deficiencies in predicting the sulfation process of limestones with a broad range of particle sizes. In this paper, the sulfation process of limestone with a broad range of particle sizes was investigated under different SO2 concentrations, CO2 concentrations, and temperatures by using a large-capacity TGA. A semi-empirical model was established based on the experimental results. It is found that the fine limestone exhibited the superior desulfurization performance compared with the coarse limestone, and it is less sensitive to the variation in SO2 concentrations. The highest ultimate conversion achieved at 850 °C–900 °C, and showed little difference between different particle sizes. Besides, the conversion and initial reaction rate increase slightly with the CO2 concentrations. The established model divided the sulfation process of limestone into the direct contact reaction on the external surface and the diffusion-controlled reaction on the inner pore surface, which can well predict the particle sizes under different SO2 concentrations.

Effect of limestone powder addition on threshold chloride concentration for steel corrosion in reinforced concrete

The effects of limestone replacement fraction, limestone specific surface area and water-to-binder (W/B) ratio on the threshold chloride concentration (TCC) for steel corrosion were evaluated. XRD and SEM analyses were conducted to examine the crystalline phases and microstructure of limestone-blended cement paste, respectively. The influence of pH value of concrete pore solution on the chloride binding capability was also investigated. The results demonstrate that the chloride threshold decreases as the limestone content or the W/B ratio increases, while limestone fineness shows negligible effect. XRD analyses indicate that addition of limestone inhibits the transformation from ettringite (AFt) to monosulfate (AFm), which exhibits superior chemical binding capability for chloride ions. SEM analyses suggest that addition of 15 wt% limestone contribute to a denser microstructure. Reduction in the pH value of pore solution compromises the chloride binding capability of concrete.

Elucidating the nano-mechanical behavior of multi-component binders for ultra-high performance concrete

The nanomechanical signature of highly heterogeneous ultra-high performance (UHP) cement pastes are explored in this paper. The UHP pastes are proportioned using 30% or 50% (by mass) of commonly available cement replacement materials including fly ash, microsilica, and fine limestone. Nanoindentation experiments coupled with a Bayesian information criterion-based statistical approach is used to develop modulus-hardness (M−H) clusters for the UHP pastes. While typical low-density (LD) and high-density (HD) C-S-H phases are present in early-age UHP pastes, it is shown that an ultra-high stiffness (UHS) phase, which is a composite of HD C-S-H and nanoscale CH, is predominant at later ages. Nanoindentation data points to the presence of significantly higher proportions of mixed phases in the UHP pastes, comprising of cement hydrates/pozzolanic reaction products and unreacted phases including fine limestone and microsilica acting as micro-aggregates to enhance the stiffness of the paste. The presence of such mixed phases complicates upscaling of the elastic modulus using multi-scale homogenization models, which is to be carefully accounted for in such highly heterogeneous systems.

Limestone particle size, calcium and phosphorus levels, and phytase effects on live performance and nutrients digestibility of broilers

Limestone particle size (PS) affects its solubility and thus can influence broiler performance by altering the rate of calcium (Ca) release into the gastrointestinal tract. The objective of this research was to determine, using 2 × 2 × 2 factorial arrangement, the influence of PS (fine and coarse) and supplemented phytase (0 and 1,000 FYT/kg) in diets formulated with 2 Ca and Pi levels (positive control [PC]; negative control [NC]) on live performance, bone ash, and apparent ileal nutrients digestibility (AID). Starter PC: 0.9 Ca and 0.45 Pi; NC: 0.72 Ca and 0.03 Pi. Grower PC: 0.76 Ca and 0.38 Pi; NC: 0.58 Ca and 0.23 Pi. The 8 diets were assigned randomly to a total of 1,512 birds, with 21 birds per pen and 9 pens per treatment. The main effects of PS and Ca and Pi levels had no influence on feed intake (FI), body weight gain (BWG), or feed conversion ratio. Adding phytase improved BWG by 8 g and 50 g and FI by 25 g and 56 g at 0–14 D (P ≤ 0.05) and 0–35 D (P ≤ 0.05), respectively. Interaction between Ca and Pi levels and phytase improved BWG and FI for 0–14 D (P ≤ 0.05) and BWG during 15–28 D (P ≤ 0.05) for PC without phytase and for PC and NC with phytase when compared with NC without phytase. Birds fed PC without phytase, or either PC or NC with phytase were about 96 g heavier than NC without phytase. Birds fed either PC or NC diet with coarse limestone or PC with fine limestone gained approximately 14 g more (P ≤ 0.05) than birds fed NC with fine limestone for BWG at 0–14 D (P ≤ 0.05). Phytase increased tibia bone ash (14 D) by 1% (P ≤ 0.05). AID of Ca and Pi at 14 D was improved (P ≤ 0.05) by 66% when phytase was added to coarse limestone. Results indicate that phytase improved broiler performance without being affected by PS. Furthermore, phytase had greater influence on coarse limestone than on fine limestone for bone ash and AID. Ca and Pi levels were the most influential factors in determining bone ash although phytase inclusion could lead to an improvement during early days.

Fine-grained limestone concrete with improved dissipative properties

Crack propagation in concrete is known to be partially stipulated by the process of energy dissipation. In this study the usage of complex admixture including limestone fines and superplasticizer which enhance crack propagation energy dissipation rate is discussed. Energy dissipation rate and crack propagation are assessed by comparing cracking strains and stress intensity ratios for two sets of specimens, with and without limestone fines. Limestone semi-inert filler acting in a synergetic way with superplasticizer is revealed to enhance crack propagation energy dissipation rate and cracking strains, which makes fine-grained limestone concrete the effective crack-resisting material.

Comparative study of soil stabilization with glass powder, plastic and e-waste: A review

In the Indian subcontinent, some soils possess significantly low California Bearing Ratio (CBR) and shear strength. Such soils cannot withstand heavy loads. So, to overcome such problems treatment of soil is needed to be done using different stabilizers like furnace slag, limestone fines, bitumen, etc. However, some of these materials have problems with seasonal variations and flakiness behavior. Hence, instability of the foundation of buildings and subgrade of roads may occur. So, we need to look up for new additive materials including modern wastes. This review paper is aimed at providing two solutions, the first one is towards a comparative study of modern wastes like glass powder, plastic, and e-waste in soil stabilization and the other one is with the disposal problem of these wastes. For this various laboratory test results on soil like Unconfined Compressive Strength (UCS), CBR, Proctor Test (PT), etc. were studied and compared by analyzing the known test results of the previous research studies.

EVALUATION OF EFFECT OF BLEND OF LIMESTONE AND GYPSUM ON THE COMPRESSIVE STRENGTH OF PORTLAND BLENDED CEMENT

The substitution of 5% cement clinker by 5% gypsum or 5% limestone additive as well as the fineness of limestone was studied about its effects on the strength of cement. The study show that the gypsum additive of 5% increase the strength of cement at the time of 1, 3, 7, 28 days (R= 55.1 MPa of cement with 5% substituted additive comparable to R= 45.3 MPa of cement with 100% clinker at the time of 28 days). The limestone additive of 5% increase the strength of cement at the early time of 1, 3, 7 days (R= 46.0 MPa of cement with 5% limestone additive comparable to R= 31.6 MPa of cement with 100% clinker at the time of 7 days). As well as, the strength of cement increase when the fineness of limestone increase.

Filler Effect in Shotcrete.

The effects of fine limestone powder on the early hydration of cementitious systems accelerated by means of alkali-free aluminum sulfate based products, commonly used for shotcrete applications, were investigated in the course of laboratory and real scale tests. In binary (CEM I + limestone) and ternary (CEM I + limestone + slag) systems the addition of fine limestone led to an enhancement of the hydration degree and strength development at early times (<24 h). The formation of ettringite, aluminate hydrates, and C–S–H is affected by the joint action of the setting accelerator and the fine limestone. Accelerator and limestone, in combination with the cement, can be optimized to enhance ettringite and silicate reaction, in some cases coupled with aluminate reaction inhibition, to produce mixes suitable for sprayed concrete applications. Such optimization can help to reduce the cement content in the mixes without compromising the early strength development of the shotcrete.

EFFECT OF LIMESTONE SIZE PARTICLES ON IMPROVING EGGSHELL AND BONE PHYSICAL AND MECHANICAL CHARACTERISTICS AT THE PEAK OF EGG PRODUCTION IN GOLDEN MONTAZAH CHICKEN

This study investigated the influence of different particle sizes of limestone in Golden Montazah layers diets on physical and mechanical properties of egg production, eggshell quality and breaking strength of tibia from 32 to 44 weeks of age. Limestone consisted of fine (F> 0.6 mm) and coarse (C>2.8mm-4.5mm). All hens take a basal ration of the same composition. The differences between the four equal groups were in the replacement percent of fine pulverised limestone by granular limestone, of coarser particle size. The control group takes the basal diet with only pulverised limestone as a calcium supplement. In the diet ration of the second group, 60% of the pulverised limestone was replaced with granular limestone, in the third group percent 80 % and in the last group 100% of fine limestone replaced with coarse particles of limestone. Significantly higher breaking force (31.69N), shell weight (5.65 g), shell thickness (0.46 mm) were found for eggs from the fourth group of hens than for eggs from the control group (29.46 N; 5.33 g ; 0.37 respectively). Tibia breaking strength was significantly higher (350.66 N) than those in control group (252.82 N). The results obtained in our investigation showed some possibilities of eggshell quality improvement using limestone of coarser particle size as a Ca supplement in the hen diet. Replacing 60-100% of fine limestone by coarser particle size limestone had positive effects on eggshell quality.

Fine limestone dust from ornamental stone factories: A potential filler for a high-performance cementitious matrix

The benefits of using waste materials as supplementary cementitious materials (ASCMs) become greater as their use will minimize the chemical, biological and even visual pollutions caused when they are left in an unexploited form. For example, the estimated amount of industrial fine limestone dust (FLSD) released from ornamental stone factories is enormous. Accordingly, efficient recycling of these types of dusts in concrete provides many ecological and economic advantages. FLSD particles were found to have a spherical morphology due to the grinding and polishing steps used in the factories causing their emission. In this research, FLSD has been incorporated into different cement pastes. These pastes contained different replacement levels of 0, 15, 30 and 45% FLSD at various water-to-binder (W/B) ratios of 0.25, 0.35 and 0.45. They have been subjected to the effect of normal and sulfate attack conditions. The results showed that the paste mixture with a high FLSD replacement level did not demand for higher superplasticizer dosage in contrary to other types of dusts while gaining a high resistance to sulfate exposure. It has also been shown that the mixtures with 45% FLSD had the minimum deterioration due to sulfate effect. In addition, at a low W/B ratio of 0.25, the resistance to sulfate attack was significant, as confirmed using ultrasonic pulse velocity (UPV) and microstructure analyses. The mixture with W/B ratio of 0.25 and 45% FLSD has been deemed the optimum for the use in formulating high performance concrete. FLSD is proposed as a fine material with a high potential as a filler for HPC.

Attrition of binary mixtures of solids in a jet attrition unit

The attrition of binary mixtures of iron powder, as a representative oxygen carrier, and limestone, as a CO2 sorbent, was investigated to examine the interactions of two different solid species. An air-jet apparatus based on ASTM D5757, with several improvements, was used to test particle attrition for various times (3, 6 and 12 h), temperatures (20, 250 and 500 °C), gas flow rates (6, 8 and 10 LPM) and particle mixture compositions (Iron:Limestone mass ratios 1:0, 0.75:0.25, 0.5:0.5, 0.25:0.75 and 0:1). Attrition was affected by the fluidization velocity in relation to the minimum fluidization velocities of the two species, and the mixture mass ratio. High temperature increased the generation of iron fines, while reducing the production of limestone fines. As expected, increasing the air flow rate led to the generation of more fines of both iron and limestone.