Influence Of Limestone Research Articles

Influence of limestone and anthropogenic activities on land snail communities in Satun Province, Thailand

Southeast Asia is renowned for its rich biodiversity and serves as a global hotspot for organisms. Satun Province, located in southern Thailand, represents a significant biogeographic and biodiversity region situated in the transition zone between the Indochinese and Sundaland hotspots. Thus, Satun Province has high diversity and abundance of organisms, especially land snails. However, Satun Province has been largely understudied for both diversity and biogeography. Our study aimed to investigate land snail communities, emphasizing comparisons between the mainland and island sites, and the influence of limestone and other rock types in Satun Province. Our exploration efforts identified a diverse land snail community comprising 17 families, which updated the total reported species in the province from 22 to 58 species. The results showed that islands had significantly greater land snail species richness and abundance, and larger Shannon index values in comparison to the mainland. Anthropogenic activities on the mainland led to habitat transformation and had detrimental impacts on native land snail diversity while promoting the spread of invasive species. In contrast, the presence of little-disturbed limestone habitats on some of the islands contributed to higher richness of land snails, as limestone areas are known for their high diversity and endemism. Snail communities varied along site characteristics; especially, limestone versus non-limestone areas and human activity levels (which were associated with national park protection), with limestone and protected areas having the highest diversity. Our study illustrates the value of protected areas as potential hotspots of biodiversity, especially for islands that are little disturbed by human activities and that have habitats that support high diversity, such as limestone outcrops. This study provides valuable insights into the biogeography of land snails in Satun Province and Southeast Asia and contributes to our understanding of the factors influencing land snail diversity.

Research Progress on the Hydration of Portland Cement with Calcined Clay and Limestone

The use of calcined clay and limestone as supplementary cementitious materials, can have a certain influence on the hydration of Portland cement. This paper reviewed the influence of limestone and calcined clay and the mixture of limestone and calcined clay on the hydration of cement. Both limestone and calcined clay accelerate the hydration reaction in the early hydration age and enhance the properties of cement. Limestone reacts with C3A to form carboaluminate, which indirectly stabilized the presence of ettringite, while calcined clay consumed portlandite to form C-(A)-S-H gel, additional hydration products promote the densification of pore structure and increase the mechanical properties. The synergistic effect of calcined clay and limestone stabilize the existence of ettringite and stimulate the further formation of carboaluminate, as well as the C-(A)-S-H gel, contributed to a dense microstructure.

Characterization study on the influence of limestone and shell lime as a fine aggregate substitute: A traditional approach on lime plaster restoration

The present scenario on the rapid globalization and industrial use of natural resources across the globe has made this investigation to benefit on the utilization of crushed limestone (LSM) and shell lime (SLM) as aggregate substitutes to conventional lime mortar. Physio-chemical and modern analytical methods like XRD, TGA, FT-IR and strength test were performed, evaluating the performance of mortars with modern substitutes. Carbonate polymorphs such as calcite, vaterite & aragonite were majorly depicted in all the mortars. XRD reveals the high ranged CSH formation in limestone and shell lime mortar for 28 & 56 days. FT-IR results indicated the presence of high range calcite peaks and increased portlandite peaks at 3640 cm−1 for shell lime and limestone mortar on 56 days respectively. TGA concluded with high decarbonation occurred at 750–760 °C for shell lime & limestone mortar. The mechanical strength of LSM has peaked up to 1.58 and 1.77 MPa along with gradual strength gain around 1.54 and 1.57 MPa for SLM mix with 0.98 & 1.55 MPa for conventional mortar for 28 and 56 days respectively. Modified Limestone mortar revealed the enhanced strength up to 11.2% on natural carbonation.

Influence of Limestone and Gypsum Application on Chemical Attributes of Dystrophic Yellow Latosol Soil and Corn Yield in Eastern Amazon

The objective of this study was to evaluate changes in the chemical attributes of the soil caused by the use of limestone associated or not to with gypsum in no-tillage system. The experiment was conducted on a dystrophic Yellow Latosol in Pará state, Brazil. The experimental design was in randomized blocks in split plots with three replications. The treatments consisted of five doses of limestone (0, 1, 2, 3 and 4 t ha-1), with and without gypsum (0, 0.5 and 1 t ha-1). Soil samples were collected at depths of 0-20 and 20-40 cm. There was a significant effect on the analyzed variables at both depths. The doses of 3.64 and 2.19 t ha-1 of limestone associated with 0.5 t ha-1 of gypsum, were responsible for the largest increase in soil calcium content in the 0-20 and 20-40 cm layers, respectively. The highest increase in Ca + Mg content was found at 3.63 t ha-1 limestone combined with 0.5 t ha-1 gypsum. It was observed that 3.13 t ha-1 of limestone combined with 0.5 t of gypsum increased soil CEC. The 2.89 t ha-1 dose of limestone combined with 0.5 t of gypsum contributed to the increase in base saturation (V%). The use of limestone and gypsum promotes soil chemical conditions, as reflected by increased corn yield when compared with control (no treatment) plots.

Influence of gypsum and limestone, used as mineral additives, on autoclaved aerated concrete properties

AbstractGypsum is a very popular mineral additive used in autoclaved aerated concrete (AAC) technology. In many studies, tobermorite can be synthesized from calcium‐silicate‐hydrate (C‐S‐H) phase under hydrothermal conditions in the presence of gypsum, and its impact on the tobermorite content in the AAC blocks has been discussed. It has been found in a previous study that tobermorite can be synthesized from katoite (Ca3Al2[SiO4]3‐x(OH)4x, where x = 1.5–3.0). Probably, it is the reason why Al additives accelerated tobermorite formation in the AAC process. Another very popular mineral additive is limestone. Calcite, in particular limestone, accelerates the reaction between alite with water and forms C‐S‐H phase, which may have an impact on tobermorite formation under hydrothermal treatment. The impact of limestone and gypsum as additives on phase composition and properties of AAC was determined. In the initial study on the laboratory scale, influence of limestone on the microstructure of AAC was determined. Later, on a technical scale, properties such as compressive strength, dry density, thermal conductivity coefficient, drying shrinkage, and phase composition for blocks of AAC containing gypsum additive or calcite additive were studied.

Product gas composition for steam-oxygen fluidized bed gasification of dried sewage sludge, straw pellets and wood pellets and the influence of limestone as bed material

This is a study on gasification of low cost biogenic fuels for synthesis gas production with assessment of the gas composition and impurity concentrations. Experiments were carried out in a 20 kW fuel input bubbling fluidized bed facility with steam and oxygen as gasification agents. Dried sewage sludge, straw pellets and, for reference, wood pellets were used as fuels. The influence of limestone as low cost bed material acting as in-situ tar cracking catalyst and sulfur sorbent was analyzed. In terms of product gas quality and the influence of limestone as bed material, it can be summarized: (i) Regarding permanent gases, all fuels yielded comparable gas composition and output on water and ash free basis. The gas contains 40% H2 and 20% CO (dry mole fraction) and is thus suitable for synthesis. (ii) The gravimetric tar concentration of the product gases varied between 15 and 28 g m−³ for experiments with inert silica sand or ash bed, but could be reduced significantly by addition of calcined limestone to below 6 g m−³. As a novel approach, also the elemental composition of the gravimetric tar was analyzed. (iii) Since straw and sewage sludge contain significant amounts of nitrogen, sulfur and chlorine, the concentrations of H2S, NH3 and HCl in the syngas have been measured by wet chemical methods for these fuels. Limestone acts as sulfur sorbent and it was shown, that the H2S content of the product gas could be lowered significantly, reducing the effort of downstream gas cleaning.

Yield of Brachiaria in Function of Natural Phosphate Application and Liming in Pará Northeast

Forage plants of the genus Brachiária show excellent adaptation to poor soils with high acidity in the region. They present good response to phosphate fertilization and tolerant to soil with higher humidity. The soils of Amazonia are characterized mainly by high acidity, low availability of phosphorus and high saturation of aluminum. Under these conditions, aluminum tends to fix the phosphorus, making it necessary to apply higher doses to supply the need for fodder, justifying the need to apply corrective acidity material. The objective was to evaluate the pH of the behavior and productivity of Brachiaria brizantha cv. Xaraés by using Arad rock phosphate and limestone dolomite in a yellow Latosol of medium texture collected from the 0-20 cm layer. The treatments were: soil only (T1); soil with the addition of lime (T2); soil with added Arad 30 days before planting (T3); soil with the addition of Arad on planting (T4); soil with the addition of Arad and liming 30 days before planting (T5); and soil with the addition of Arad and liming on planting (T6), distributed in five replications, totaling 30 experimental units. At 45 days of germination, evaluated the plant height (HP) and number of leaves (NL), culminating with the courts to obtain the shoot fresh matter (SFM) and dry matter (FDM), the other cuts made every 30 days. pH variations responded positively to the treatments using lime to increase the pH to levels close to 6.5. For HP variables, NL, SFM and SDM the highest increases were obtained for treatments under the influence of limestone (T2) and limestone + Arad 30 days before planting (T5). The natural phosphate fertilizer in combination with liming showed significant results for all parameters.

Influence of limestone on the hydration of ternary slag cements

The hydration kinetics, microstructure and pore solution composition of ternary slag-limestone cement have been investigated. Commercial CEM I 52.5 R was blended with slag and limestone; maintaining a clinker to SCM ratio of 50:50 with up to 20% slag replaced by limestone. The sulphate content was maintained at 3% in all composite systems. Hydration was followed by a combination of isothermal calorimetry, chemical shrinkage, scanning electron microscopy, and thermogravimetric analysis. The hydration of slag was also followed by SEM image analysis and the QXRD/PONKCS method. The accuracy of the calibrated PONKCS phase was assessed on slag and corundum mixes of varying ratios, at different water/solid ratios. Thus, the method was used to analyse hydrated cement without dehydrating the specimens. The results show that the presence of limestone enhanced both clinker and slag hydration. The pore volume and pore solution chemistry were further examined to clarify the synergistic effects. The nucleation effects account for enhanced clinker hydration while the space available for hydrate growth plus the lowering of the aluminium concentration in the pore solution led to the improved slag hydration.

The role of limestone during fluidized bed oxy-combustion of coal and biomass

The interest in bio-CCS technologies is growing due to their potential to reduce CO2 emission in power generation. Oxy-co-firing in fluidized-bed units is one of the available techniques to develop bio-CCS, offering wide fuel flexibility and low SO2 and NOx emissions. This paper discusses the results of an experimental campaign carried out in a lab-scale fluidized bed reactor. The work focuses on the influence of limestone when oxy-firing blends of lignite and corn stover. Two different types of limestone with two Ca:S molar ratios were tested, and operational conditions were selected to compare the mechanisms governing desulphurization. Emissions of SO2, NO and HCl, together with deposition rates and ash mineralogy are studied in the paper. SO2 capture increases with the Ca:S ratio and bed temperature, but to a different extent depending on the limestone fragmentation. The amount of NO emitted rises with the Ca:S ratio and the presence of calcined limestone (indirect desulphurization). The HCl concentration in the gas phase is dominated by alkali sulfation. Finally, the conditions for the highest desulphurization efficiency diminished the deposition rates, but increased the risk for chlorine-induced corrosion.

The Influence of Limestone And Calcium Hydroxide Addition in Asphalt Concrete Mixture

As time passes, flood often occurs in the area of Gunung Sahari, Jakarta Utara. The flood damages concrete asphalt mixture and it needs particular improvement. Therefore, the purpose of this research is to know the effects of the added combination of limestone and calcium hydroxide on concrete asphalt mixture as a filler resistant to flood. Concrete asphalt mixture that filled with the combination of limestone and calcium hydroxide is a mixture that is made with non-uniform aggregat gradations, filler and liquid asphalt mixed and solidified in a heat state. Limestone and calcium hydroxide mixture is used because both materials included in the most numerous sedimentary rock. Concrete asphalt mixture with the filler combination of limestone and calciumhydroxide is made with optimum asphalt 5.4%, one variation level of limestone (15%), and calcium hydroxide (15%), and three variation levels of fillers (5%, 7.5%, and 15%) to get optimum asphalt levels and filler levels that are compatible with flood condition. Based on optimum asphalt 5.4% towards aggregate total weight and combined level of limestone and calcium hydroxide suitable for the conditions, 8.75 % towards fine aggregate weight. The characteristic value of limestone and calcium hydroxide mixture in maximum condition is VIM 4.55%, VMA 18.83%, stability 1031.26 kg and flow 4.93 mm, where the characteristic value meets the established specifications standard by Pekerjaan Umum Bina Marga. From the result, it is showed that the use of the mixture can decrease the value of stability and increase the value of flow, compared with asphalt and filler with normal levels.

Influence of Limestone and Fly Ash (Class F) as Partial Replacement Materials on the Mechanical Properties of Concrete

Influence of Limestone and Fly Ash (Class F) as Partial Replacement Materials on the Mechanical Properties of Concrete

The Influence of Limestone and Al2O3 Content in the Slag on the Performance of the Composite Cements

In the present contribution, the interaction between limestone and slag is investigated by a multi-method approach using chemical shrinkage, thermogravimetry, scanning electron microscopy (SEM) techniques and compressive strength measurements. The impact of limestone was investigated in blends containing synthetic slags of different alumina content. The results are correlated with the thermodynamic modelling in order to gain further insights into the physical and chemical processes governing the interaction between limestone, slag and Portland cement.Beyond 28 days of hydration, slag composites exhibit higher compressive strength values than their equivalent with quartz. Increasing the Al2O3 content from 8 to 12% in slag influenced compressive strengths positively at all hydration times. Further increase of alumina in slag to 16% has no positive effect on strength. Addition of limestone, results positively only on early compressive strengths. After 28 days and longer effect of limestone is either slightly negative or neutral. Only in the case of the slag containing 16% of alumina, limestone has positive impact on the late compressive strength. The effect of limestone has two main components: physical, so called filler effect and chemical that depends on the slag composition.

Influence of limestone and anhydrite on the hydration of Portland cements

The addition of CaCO3 and CaSO4 to Portland cement clinker influences the hydration and the strength development. An increase of the CaSO4 content accelerates alite reaction during the first days and results in the formation of more ettringite, thus in a higher early compressive strength. The late compressive strength is decreased in Portland cements containing higher quantities of CaSO4. The reduced late compressive strength seems to be related to an increase of the S/Si and Ca/Si content in the C–S–H.The presence of calcite leads to the formation of hemicarbonate and monocarbonate thus indirectly to more ettringite. Only a relatively small quantity of calcite reacts to form monocarbonate or hemicarbonate in Portland cement. Although hemicarbonate is thermodynamically less stable than monocarbonate, hemicarbonate formation is kinetically favored. Monocarbonate is present only after 1week and longer independent of the quantity of calcite available and the content of sulphate in the cement.

Influence of limestone and slag on the pore structure of cement paste based on mercury intrusion porosimetry and water vapour sorption measurements

The objective of this study is to evaluate the responsiveness of mercury intrusion porosimetry (MIP) and dynamic water vapour sorption (DWVS) experiments to reflect changes to the pore structure of cement paste due to the influence of cementing material type. The DWVS isotherms are used to evaluate the pore size distribution and specific surface area. The MIP test is used to characterize the threshold diameter, and total porosity of the specimens. This study examines the influence of four cement paste mixture designs, namely 100% general use (GU) Portland cement, 50% GU+50% ground granulated blast furnace slag (GGBFS), 100% Portland limestone cement (PLC), and 50% PLC+50% GGBFS. The specimens were aged for one year in saturated limewater. The results indicate that DWVS is sensitive to changes in microstructure resulting from GGBFS and PLC inclusions. The Barrett Joyner Halenda (BJH) pore size distributions indicate that the effect of GGBFS and PLC inclusions have a marked effect on pores smaller than 4nm diameter and a slight effect on pores between 4 and 10nm in diameter. Characterization of the paste microstructure using both DWVS and MIP techniques provide a description of pores ranging from less than 1nm in diameter to up to 8μm. Both methods are well suited to detect changes due to moisture-binder and the cementing material type (GGBFS and PLC).

Chloride binding into hydrated blended cements: The influence of limestone and alkalinity

Chloride binding into ten hydrated cement binders containing limestone and different pozzolanic materials was systematically investigated. The results showed that the amount of bound chloride in pozzolan-blended cements strongly depended on the content of aluminum in the binder. The presence of limestone in cement significantly decreased chloride binding capacity under the condition of common alkalinity (pH≈13.5). The effect of limestone seemed to be related to decreased ability of chloride binding into carboaluminate phases that formed during the hydration of calcium carbonate-containing cement. Alkalinity of the synthetic pore solution generally influenced the course of binding with the effect being more pronounced at lower chloride concentrations. The presence of alkalis hindered the formation of chloroaluminate phases and decreased the chloride binding capacity. Lowering of the temperature resulted in a decreased amount of bound chloride. The reversibility of chloride binding was largely maintained under the condition of constant alkalinity.

Influence of limestone and amphibolite application on growth of Norway spruce plantation under harsh mountain conditions

  The results of a fifteen-year period of investigations conducted on Norway spruce in the upper plateau of the Jizerské hory Mts. were summarised. The objectives were to evaluate the growth performance of an experimental plantation under harsh environmental conditions and assess the effects of amendments as well as the influence of the forest site variability on growth performance and survival of young spruces. The following treatments were distinguished: (1) lower control, (2) limestone and (3) amphibolite treatments on a less exposed slope of the ridge and (4) upper control on a summit of the mountain ridge. Principle characteristics such as mortality rate, height, annual height increment, stem base diameter, crown diameter and nutritional status were summarized and evaluated. Significant differences between treatments were recorded in heights. The trees fertilized with amphibolite were significantly taller than the control ones in thirteen out of the fifteen evaluated years and the applied limestone improved heights in ten years out of the fifteen evaluated years. A positive effect of amphibolite treatment on stem base diameter was proved in three of the four assessed years and was persisting till 2007 (last measurement of this characteristic), the positive effect of limestone was lasting up to 2006. The considerable role of the site variability was apparent from a comparison between the upper and lower control although they were in a very close position to each other, growth increment of the spruces on the ridge was significantly lower. Temporarily lower N concentration was recorded in the fertilized treatments in comparison with their respective control. The concentration of P was low and decreased to the limit of deficiency in all treatments, P seems to be the most limiting macroelement in the area.  

Influence of limestone and phytase on broiler performance, gastrointestinal pH, and apparent ileal nutrient digestibility

An experiment was conducted to determine the influence of 2 levels of dietary Ca from limestone and 3 levels of phytase on broiler performance, bone ash, gastrointestinal pH, and apparent ileal digestibility (AID) of Ca, P, and amino acids. Cobb 500 broilers (n = 576) were allowed access to one of 6 corn-soy diets from 0 to 16 d. Experimental diets contained 1.03% or 0.64% Ca from limestone and 0.61% total P. Each diet was supplemented with 0, 500, or 5,000 FTU/kg of phytase to create a 2 × 3 factorial experiment. Broiler feed intake (FI) and BW gain were not affected by dietary Ca or phytase. Feed conversion ratio was improved (P < 0.05) as dietary phytase increased (1.36, 1.34, and 1.31, respectively). Tibia ash percent was reduced (P < 0.05) from 41.4 to 40.0% as dietary Ca decreased but increased with phytase addition (P < 0.05). Gizzard and ileal pH were reduced (P < 0.05) in broilers fed 0.64% Ca compared with broilers fed 1.03% Ca. Phytase at 5,000 FTU/kg increased (P < 0.05) pH in the gizzard, duodenum, jejunum, and ileum. Apparent ileal P digestibility was increased (P < 0.05) in broilers fed 0.64% Ca compared with broilers fed 1.03% Ca (0.68 vs. 0.73, respectively). Apparent ileal Ca digestibility was increased (P < 0.05) in broilers fed 1.03% Ca compared with broilers fed 0.64% Ca (0.67 vs. 0.53, respectively). Phytase improved AID of CP in broilers fed 1.0% Ca but did not have an effect on AID of CP in broilers fed 0.64% Ca, which resulted in a Ca × phytase interaction (P < 0.05). In conclusion, high dietary Ca increased pH in gizzard and ileum and interfered with the AID of P and CP. The interactions between Ca and phytase in the gastrointestinal tract are complex, and feeding phytase at doses above industry recommendations may allow for reduced-Ca diets while maintaining broiler performance, bone ash, and improving amino acid digestibility.

Influence of limestone on the hydration of Portland cements

The influence of the presence of limestone on the hydration of Portland cement was investigated. Blending of Portland cement with limestone was found to influence the hydrate assemblage of the hydrated cement. Thermodynamic calculations as well as experimental observations indicated that in the presence of limestone, monocarbonate instead of monosulfate was stable. Thermodynamic modelling showed that the stabilisation of monocarbonate in the presence of limestone indirectly stabilised ettringite leading to a corresponding increase of the total volume of the hydrate phase and a decrease of porosity. The measured difference in porosity between the “limestone-free” cement, which contained less than 0.3% CO 2, and a cement containing 4% limestone, however, was much smaller than calculated. Coupling of thermodynamic modelling with a set of kinetic equations which described the dissolution of the clinker, predicted quantitatively the amount of hydrates. The quantities of ettringite, portlandite and amorphous phase as determined by TGA and XRD agreed well with the calculated amounts of these phases after different periods of time. The findings in this paper show that changes in the bulk composition of hydrating cements can be followed by coupled thermodynamic models. Comparison between experimental and modelled data helps to understand in more detail the dominating processes during cement hydration.

A thermodynamic and experimental study of the conditions of thaumasite formation

The formation of thaumasite was investigated with the progressive equilibrium approach (PEA). This approach experimentally simulates the conditions of various levels of sulfate addition in hardened cement pastes. The influence of limestone, time, C 3A content, temperature and leaching on thaumasite formation was investigated. The results show that thaumasite formation is favoured at lower temperatures (8 °C) independently of the type of cement clinker (high or low C 3A content) used. Thaumasite was found to form only in systems where limestone was present and where sufficient sulfate had been added. Thaumasite precipitated only in systems where the Al present has already been consumed to form ettringite and the molar SO 3/Al 2O 3 ratio exceeded 3. In leached samples (reduction of portlandite and alkalis) slightly less thaumasite was formed whereas gypsum and ettringite are favoured under these conditions. The PEA, used to investigate the chemical aspects of sulfate attack was found to be a good tool for simulating external sulfate attack. Generally, thaumasite was detected were it was modelled to be stable in significant amounts. However, in this study equilibrium conditions were not reached after 9 months.

焼結過程における通気性と焼結鉱品質に及ぼす擬似粒子中の石灰石と粉コークスの賦存状態の影響

焼結過程における通気性と焼結鉱品質に及ぼす擬似粒子中の石灰石と粉コークスの賦存状態の影響