Chemical, Mechanical, and Durability Properties of Concrete with Local Mineral Admixtures under Sulfate Environment in Northwest China (original) (raw)
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The influence of mineral admixtures on the short and long-term performance of concrete
Building and Environment, 2007
This paper presents a laboratory study on the performance of concrete by adding mineral admixtures, silica fumes (SF) or/and fly ash (FA). Performance of the concrete mixes was determined with short and long-term tests, which include compressive strength, porosity, capillary absorption, wet-dry cycle and accelerated carbonation. The test results, in general, showed that mineral admixtures improved the performance of concretes. SF contributed to both short and long-term properties of concrete, whereas FA shows its beneficial effect in a relatively longer time. As far as the compressive strength is concerned, adding of both SF and FA slightly increased compressive strength, but contributed more to the improvement of transport properties of concretes.
The Effect of Different Mineral Admixtures on Characteristics of Concrete
This paper presents a review of the properties of fresh and hardened concrete by using mineral admixtures fly ash (FA), and silica fume (SF). In many countries, these materials are already used in manufacturing of concrete. However, these industrial by products is becoming popular throughout the world because of the minimization of their potential hazardous effects on environment. Some of these materials used as replacement for cement. Ultimately it results in the reduction of the cost manufacturing of concrete and reduces environmental pollution. In general, small particle size and higher specific surface area of mineral admixture are favorable to produce highly dense and impermeable concrete; however, they cause low workability and demand more water. To study the effect of mineral admixtures such as fly ash and silica fume on mechanical properties of concrete under the uniaxial compression experimental studies conducted. The cement was replaced by 10 %, 20 % and 30 % with fly ash and silica fume. The compressive strength test conducted on concrete specimen with different percentages of fly ash and silica fume at age of 7 days and 28 days.
Effect of mineral additives on some of durability parameters of concrete
Reducing the greenhouse gas emissions is essential for sustainable development particularly the carbon dioxide (CO 2). The manufacturing of Portland cement is a highly energy-intensive process requiring about four Giga Joules (4GJ) of energy per tonne of finished product. The less energy intensive materials being sought are industrial by-products that are easily available, require little or no pyro-processing and have inherent or latent cementitious properties. Reducing the cement content in concrete by 40%-60% contributes to reduce CO 2 emissions. A part of the cement content can be replaced by fly ash and other supplementary materials and high range water reducing admixtures. Use of additive minerals improves pozzolanic reaction, micro-aggregate filling and concrete durability. Long term investigations have confirmed that cements containing slag and condensed silica fume impart better resistance to formation of large pores of cement clay or cement-silica fume paste systems, consequently to a decrease in the permeability. The present paper brings the past, present and expected future in the field of concrete with additive minerals using less cement. Studies have been performed on the durability of these concretes under different environmental conditions. Parameters like compressive strength, shrinkage, effects of carbonation and acid attacks have been measured.
Effect of Mineral Admixtures in Concrete
2018
The main focus of the present study is to analyse the effect of partial replacement of cement with minerals on the properties of concrete. In view of global warming, Cement industry is a major contributor in the emission of CO2 and the use of high level of energy resources in the production of cement leads to depletion of natural resources. In this present study, an attempt has been made to utilise the use of industrial and agricultural byproduct waste as a mineral admixture in concrete for partial replacement of cement that shall reduce waste landfill sites and pollution as well as minimize the consumption of natural resources. Among these industrial by-product are Fly Ash (FA), Silica Fume (SF), Rice Husk Ash (RHA) and Granulated blast furnace slag (BFS) for making the concrete there by reducing the CO2 emission. These mineral admixtures, commonly used in structural concrete, were studied here to assess their effect on the fresh and hardened properties of concrete. The materials w...
EFFECT OF MINERAL ADMIXTURES ON CHARACTERISTICS OF HIGH STRENGTH CONCRETE
There is great need to conserve all the natural resources. The various steps to be adopted in the direction that includes minimization of production of energy consuming materials and heavy utilization of industrial by-products. High strength concrete can be produce using such materials like fly ash, slag and silica fumes. In many countries, these materials are already used in manufacturing of concrete. Some of these material can be used as replacement for cement. Ultimately it results in the reduction of the cost manufacturing of concrete and reduces environmental pollution. To study the effect of mineral admixtures such as fly ash, slag and silica fume on mechanical properties of high strength concrete under the uniaxial compression and split tensile, experimental studies have been conducted. The cement was replaced by 5%, 10%, 15% and 20% with fly ash and slag respectively. The compressive strength and split tensile test were conducted on concrete specimen with different percentages of fly ash and slag at age of 7 days, 28 days and 56 days. This study shows that materials used in this experiment are suitable for HSC.
International journal of engineering research and technology, 2021
The construction industry is consistently under tremendous pressure to increase productivity in a sustainable way without compromising for quality. This paper contents several contemplative sections covering technical, commercial and practical aspects relevant to the use of sustainable alternatives for Portland Cement such as GGBS and Fly Ash. The properties of concrete containing GGBS and Fly Ash vary with the proportion of the material used in relation to the total cement content. As a general rule the increase in the proportion of GGBS or Fly Ash reduces the water demand, extends the setting time and the initial rate of gain of strength is slower. Potential durability of concrete made with these mineral additives is generally greater than that of normal OPC concrete. Concrete durability tests generally being specified worldwide for assessing the durability attributes and quality control of concrete are rapid chloride per meability test, water absorption, water permeability, chloride migration coefficient, porosity, capillary absorption etc. The three principal mix design criteria that affect durability of concrete are maximum free water/cement ratio, proportions of mineral additions used and the minimum cementitious content. The test conditions for durability parameters are normally based on a test age of 28 days. The use of GGBS or fly ash in concrete as supplementary cementitious material not only extends technical advantages to the properties of concrete but also contributes to the environmental pollution control. I. Normal grade structural concretes containing Fly Ash, GGBS or Silica Fume mixes can all achieve very high chloride resistance compared with Portland cement concretes. The main methods of reducing the penetration of chlorides are tabulated below: TABLE I. MEASURES FOR REDUCING CHLORIDE PENETRATION Approach Methods Concrete mix design Selection of cement type Water/Cement ratio Use of mineral additions such as GGBS, Fly Ash & Silica Fume Other measures Controlled permeability formwork Coatings Hydrophobic treatment of the concrete
The effect of mineral admixtures on the properties of high-performance concrete
Cement & Concrete Composites, 2000
The paper presents a laboratory study on the influence of two mineral admixtures, silica fume (SF) and fly ash (FA), on the properties of superplasticised high-performance concrete. Assessment of the concrete mixes was based on short- and long-term testing techniques used for the purpose of designing and controlling the quality of high-performance concrete. These include compressive strength, porosity, oxygen permeability, oxygen diffusion and chloride migration. Measurements were carried out after curing at 20% and 65% relative humidity up to the age of 1 yr. The results, in general, showed that mineral admixtures improved the properties of high-performance concretes, but at different rates depending on the binder type. While SF contributed to both short- and long-term properties of concrete, FA required a relatively longer time to get its beneficial effect. In the long term, both mineral admixtures slightly increased compressive strength by about 10%, but contributed more to the improvement of transport properties of concretes.
This paper reports a part of an ongoing experimental laboratory investigation being carried out to evaluate the mechanical properties of concrete made with mineral admixtures and local Jordanian materials. Various percentages of Silica Fume (SF) and Fly Ash (FA) were added at different water/cementitious (w/cm) ratios. Concrete specimens were tested and compared with plain concrete specimens at different ages. Results indicated that compressive as well as flexural strengths increased with mineral admixture incorporation. Optimum replacement percentage is not a constant one but depends on the w/cm ratio of the mix. SF contributed to both short and long-term properties of concrete, whereas, FA showed its beneficial effect in a relatively longer time. Adding of both SF and FA did not increase compressive strength in the short-term, but improvements were noticed in the long-term. Compared with compressive strength, flexural strength of SF concretes has exhibited greater improvements. Relationships between the 28-day flexural and compressive strengths have been developed using statistical methods. It is concluded that local concrete materials, in combination with mineral admixtures, can be utilized in making High Strength Concrete in Jordan and such concrete can be effectively used in structural applications.
Effects of Different Mineral Admixtures on the Properties of Fresh Concrete
The Scientific World Journal, 2014
This paper presents a review of the properties of fresh concrete including workability, heat of hydration, setting time, bleeding, and reactivity by using mineral admixtures fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK), and rice husk ash (RHA). Comparison of normal and high-strength concrete in which cement has been partially supplemented by mineral admixture has been considered. It has been concluded that mineral admixtures may be categorized into two groups: chemically active mineral admixtures and microfiller mineral admixtures. Chemically active mineral admixtures decrease workability and setting time of concrete but increase the heat of hydration and reactivity. On the other hand, microfiller mineral admixtures increase workability and setting time of concrete but decrease the heat of hydration and reactivity. In general, small particle size and higher specific surface area of mineral admixture are favourable to produce highly dense and impermeable concrete; however, they cause low workability and demand more water which may be offset by adding effective superplasticizer.
STUDY ON MICROSTRUCTURE AND DURABILITY PROPERTIES OF CONCRETE WITH DIFFERENT MINERAL ADMIXTURES
Concrete is the most used material in the world next to water and food materials. It is the evidence for the civilization. But the production of concrete leading to environmental degradation and pollution since it involves emission of CO2, which is the one of the reason for global warming. And the industries such as thermal power plants and steel manufacturing industries produces lots of fly ash and GGBS. The mineral admixtures such as fly ash and ground granulated blast furnace slag(GGBS) are currently using as supplementary cementitious materials (SCM) to reduce cost and environmental pollution associated with the production The main objective of present study is to investigate the effect of Fly ash and GGBS on chemical, mechanical, durable and micro structural properties.The concrete mixes were prepared by replacing 30% of cement with fly ash, GGBS and 1.2% super plasticizer (conplast SP430) and water to cement ratio 0.45 was maintained for mix design of M35 grade concrete. This study investigates the performance of concrete in terms of compressive strength at 3, 7, 28 days. durability proprties such as water absorption and sorptivity at age of 28 days. Advanced technique such as scanning electron microscope(SCM) and X-ray computed tomography(X-CT) were used to understand the effect of Fly ash and GGBS on morphology and porosity of concrete. From the present study it can be conclude that with the addition of super plastizer and mineral admixtures the compressive strength of GGBS mix was comparatively more than the compressive strength of fly ash mix. With respect to water absorption and sorptivity tests GGBS mix showed better results than the fly ash mix. From the SEM and X-CT images it is observed that concrete with GGBS improves the micro structural properties such as morphology and porosity of concrete. © 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 1723