Papers by Keyword: Limestone Powder

Abstract: The aim of this paper is to investigate two different concrete mixes, one with Limestone Powder (LSP) and the other with Ground Granulated Blast-Furnace Slag (GGBS), both mixes containing superplasticizer, in order to analyse their compressive strengths at 7 and 28 days, their abrasion resistance and slip resistance. The two mixes are treated with two different surface protection finishers, applied on the surface after the concrete has cured and analysis of how these finishers affect the abrasion resistance and slip resistance of the concrete is discussed.

Abstract: In this paper, influence of heat treatment on evolution of mechanical strengths at early age, less than 24hours of self-compacting concretes containing limestone powder and silica fume as fine materials was investigated experimentally. Two compositions of self-compacting concrete have been studied; the first is elaborated with silica fume addition and the second with limestone powder, each mixture were prepared with a constant water/binder ratio of 0.39. Concrete samples were either cured in water at (23±1°C), or steam cured at 65°C maximum temperature over six hours (6h) curing period. Tests of mechanical strengths were performed on specimens cooled down slowly to room temperature after heating.The obtained results show that all self-compacting mixtures exhibited satisfying fresh properties and check EFNARC specifications of self-compacting concrete (slump flow diameter higher than 650mm, L-box ratio higher than 80% and sieve stability less than 17%).Mechanical strengths of concrete containing limestone addition are slightly lower than those of concrete based on silica fume at all ages. Moreover, heat treatment generates an improvement of compressive and flexural strength. Interesting compressive strengths are obtained. At 24 hours, after heat treatment, the strengths are already greater than 35 MPa. The values ​​are 37 MPa and 40 MPa for self-compacting concrete containing limestone powder and silica fume respectively compared to 40 MPa and 46 MPa obtained at 7 days for the corresponding non-heat treated concretes. Compressive strength gain of SCCs mixtures with limestone powder and with silica fume, undergoing heat treatment at the age of 24hours is 85% and 75% respectively compared to SCCs mixtures cured in water.

Abstract: The effects of replacing high calcium fly ash with containment glass powder and limestone powder in the geopolymer are investigated in this paper. The high calcium fly ash was replaced by either glass powder or limestone powder at 20% and 40% by weight. The geopolymer paste was tested for setting time and compressive strength and evaluated of its microstructure on SEM, XRD, FTIR, and MIP. The results indicated that the setting time of geopolymer paste was increased with the replacement of glass powder and reduced by replacement of limestone powder. The compressive strengths were generally higher than those of controls. The maximum increase of compressive strength was 33% when replaced fly ash with 20% of glass powder at 8 molar NaOH concentration of sodium hydroxide solution. The microstructure evaluations show the remaining particles of raw materials and the compatible of hydration reaction and polymerization when having limestone powder in the mix proportion. Furthermore, the powder acts as a filler in the gels.

Abstract: Self-Consolidating Lightweight Foam Concrete (SCLFC) is known as a concrete which has no requirement towards vibration or compaction effort due to its flowability and capability in filling and achieving full compaction in reinforcement. The main component in SCLFC is cement. Cement is a basic component of concrete that used in construction industry. However, it is also the main source of Carbon Dioxide (CO₂) emission. If this component of concrete is replaced with other materials, it surely can help in reducing the emission of CO₂. Limestone powder can be replacement with the cement content in SCLFC. Therefore, the aim of this paper is to determine the effect of limestone powder on SCLFC in term of flowability and compressive strength. The specimens were tested for compressive strength at 3, 7, and 28 days. The result indicated the flowability of SCLFC increase with the increase of percentages of limestone powder replacement. Meanwhile, the highest compressive strength of SCLFC containing 10% limestone powder replacement give better performance than the normal SCLFC. Based on the finding, SCLFC containing 10% limestone powder replacement can be categorized same as a conventional concrete hence it can be utilized for construction purposes. Limestone powder can also acts as an alternative replacement in concrete for replacing the cement.

Abstract: The present study aims to investigate the engineering properties of foam lightweight material (FLM) that was produced using a mixture of ordinary Portland cement (OPC) and limestone powder (LP). The FLM samples were prepared with various proportions of LP (10%, 20%, and 30%) and different percentages of foam (9%, 12%, and 15%). Properties of the FLM were evaluated through the values of compressive strength, dry density, porosity, and thermal conductivity. Test results show that the foam contents affected all properties of the FLM significantly, whereas LP contents showed the insignificant effect to the FLM properties. Furthermore, the results of the present study showed a close correlation between porosity and other properties of the FLM as higher porosity resulted in lower density and thus lower thermal conductivity and mechanical strength.

Abstract: In this paper, we consider a method of increasing biological resistance and biological durability of buildings and constructions that are subject to destruction from the impact of microorganisms activity. This article presents the results of studies of innovative materials in the field of bioresistant building materials. Powders of milled quartz sand and limestone were the fillers for the composites. Limestone used for the experiments is from the Chechnya depostits. We have implemented optimization for the cement composites compositions using the methods of mathematical experiment design. We derived the dependences describing how the bioresistance coefficient, the elastic modulus and the water demand depend on the granulometric composition after 3 and 9 months of aging in the environment of filamentous fungi. We have found that the multifractional compositions have a higher bioresistance coefficient. We determined the fungal resist compositions.

Abstract: In this study, the effect of surface structure of nanoCaCO₃/limestone powder composite particles (NC/LS) on the hydration products of cement at early age is investigated. The surface structure of NC/LS is observed by field emission scanning electron microscope (FE-SEM) and compared with original limestone powders. X-ray diffraction (XRD) is used to investigate the types of hydration products and calculate the Ca (OH)₂ (CH) particle size and crystal orientation degree. Additionally, FE-SEM and atomic force microscopy (AFM) are applied to observe the particle size, shape and distribution of hydration products. The results reveal that the nanoCaCO₃ particles are distributed throughout the surface of limestone powders, and therefore successfully formed NC/LS. Secondly, the particle size, morphology and distribution of the cement hydration products are affected by the surface structure of NC/LS, so the microstructure of hardened cement paste at early age is enhanced.

Abstract: Since the gradation of cement-slag has significant influence on its properties, the optimal gradation of cement-slag was studied by imitating with limestone powder. From experimental results of the porosity and fluidity of limestone power and on the base of the RRB equation, the optimal gradation area was got and its rationality was confirmed by experimental results of cement-slag.

Abstract: The paper deals with self-compacting concrete (SCC) and the change of its properties after exposure to thermal loading. Two types of microfillers were used (along with appropriate amount of superplasticizer) to gain concrete which would meet the requirements for SCC – limestone powder and fly ash. Specimens were subjected to temperatures of 600 °C for 2 hours. Results proved significant worsening of all studied parameters on samples after the thermal loading. Therefore studying of material exposed to different external conditions for better simulation of real life of construction is important in future research.

Abstract: This study investigates the influence of limestone powder and silica flour used as fine mineral fillers on the main characteristics of gypsum plaster. Fine mineral fillers were added in various dosages from 2.5% to 20.0%.