نتایج جستجو برای: limestone
تعداد نتایج: 5717 فیلتر نتایج به سال:
The ASTM C150 standard specification for Portland cement now permits the cement to contain up to 5% of ground limestone. While these and much higher levels of limestone filler substitution have been employed in Europe and elsewhere for many years, changing the ASTM standard has been a slow process. Having computational tools to assist in better understanding the influence of limestone additions...
Limestone is mainly constituent of chemical compound calcium carbonate (CaCo3). It is basically called sedimentary rock substance. As per researchers it forms 10% of total volume of Sedimentary rock. The extrusion & Implementation of limestone in any form deals with ease of work and as a less pollutant for Environment, hence it can be massively used and utilized as a replacement to coarse aggre...
This document is to serve as background technical information for engineers, specifiers, and other concrete technologists on use of limestone in hydraulic cements in amounts up to 15% (focusing on amounts between 5% and 15%). The document also provides supporting data for standardization of limestone blended cements in ASTM C595 and AASHTO M240. Environmental benefits are noted as well as a his...
Over the last few years the Texas Department of Transportation has expressed concern about mineralogical segregation (variation) of coarse aggregates used in bituminous mixes; problems are associated with variation in the quality of aggregates taken from a quarry/gravel pit. The primary objective of this project was to examine the effects of poor quality coarse limestone aggregate on hotmix asp...
Limestone is widely used in the construction industry to produce Portland limestone cement (PLC) concrete. Systematic evaluations of hydration kinetics, compressive strength development, and carbonation resistance are crucial for the rational use of limestone. This study presents a hydration-based model for evaluating the influences of limestone on the strength and carbonation of concrete. Firs...
In this work we have tested the fluidized bed desulfurization performance of lime particles obtained by means of a proprietary limestone slow calcination pre-treatment technique. This performance was compared to that of the parent untreated limestone particles. The occurrence of particle fragmentation and attrition during the fluidized bed operation was also investigated with a specific test pr...
A study was conducted to determine the effect of different limestone particle sizes in layer diets on bone quality characteristics at end-of-lay hens. Calcitic limestone (360 g Ca/kg DM) that is extensively used in commercial poultry diets was obtained from a specific South African source. Limestone particles were graded as small (<1.0 mm), medium (1.0 2.0 mm) and large (2.0 3.8 mm) and include...
The Indonesian province of East Kalimantan is home to some of the largest remaining contiguous tracts of lowland Dipterocarp forest on the island of Borneo. Nest surveys recently conducted in these forests indicated the presence of a substantial population of Eastern Bornean orangutans (Pongo pygmaeus morio) in the Berau and East Kutai regencies in the northern half of the province. The Sangkul...
This study investigated the implications of using two grades of limestone from a paper and pulp industry for neutralization of acid mine drainage (AMD) in a pilot sequencing batch reactor (SBR). In this regard, two grades of calcium carbonate were used to neutralize AMD in a SBR with a hydraulic retention time (including settling) of 100 min and a sludge retention time of 360 min, by simultaneo...
An examination of defluoridation by industrial grade limestone indicated that a combination of precipitation and adsorption of fluoride can be more effective for defluoridation of water. Pre-acidified fluoride water using two edible acids, viz., acetic acid (AA) and citric acid (CA) have been used for treatment by crushed limestone of diameter 3-4 mm to precipitate fluoride as CaF2 in addition ...
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