scholarly journals Eco-Efficient Hybrid Cements: Pozzolanic, Mechanical and Abrasion Properties

2020 ◽  
Vol 10 (24) ◽  
pp. 8986
Author(s):  
Segundo Shagñay ◽  
Leticia Ramón ◽  
María Fernández-Álvarez ◽  
Asunción Bautista ◽  
Francisco Velasco ◽  
...  
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Cement Industry ◽  
Pozzolanic Activity ◽  
Partial Replacement ◽  
Mechanical Resistance ◽  
Abrasion Test ◽  
Cement Ratio ◽  
Activated Slag ◽  
Substitute Materials

One of the most polluting industries is the cement industry and, for this reason, alternative lines of research recommend the use of substitute materials for traditional Portland cement. This study proposes the use of industrial (slag and fly ash) and ceramic wastes for the total or partial replacement of Portland cement in the manufacturing of both alkaline-activated and hybrid cements. To carry out this study and evaluate the behavior of the proposed materials, different mortars were manufactured: Portland cement (CEM I), two alkaline-activated slag systems and six hybrid systems, with an 80–20% waste-to-Portland-cement ratio for all the proposed wastes. An assessment of the pozzolanic activity was carried out for the different materials. The behavior of all the systems regarding mechanical resistance and durability to abrasion was studied. All the proposed materials, especially those with ceramic wastes, showed pozzolanic activity and suitable characteristics for use in the manufacturing of alternative cements. The mortar made of slag activated with waterglass presented the highest mechanical strength and lowest porosity, but the hybrid materials presented competitive results. After being subjected to the Böhme abrasion test, their effectiveness as substitutes for Portland cement is reiterated, some of them improving their durability to wear.

scholarly journals Partial Replacement of Cement by Neem Leaves Ash and Fly Ash

2020 ◽  
Vol 9 (1) ◽  
pp. 506-508
Keyword(s):  
Experimental Investigation ◽  
Fly Ash ◽  
Ordinary Portland Cement ◽  
Construction Materials ◽  
Strength Properties ◽  
Vital Role ◽  
Partial Replacement ◽  
Cement Ratio ◽  
Neem Leaves ◽  
The World

Concrete is the most essential construction materials in all over the world. It is necessary to search the cheaply obtainable material as admixture which might be partially replaced cement in the production of concrete. This project is an experimental investigation of the neem leaves ash as partial replacement for cement also fly ash is used for partial replacement of cement. The neem leaves were dried, burnt and heated in the furnace to produce Neem leaves Ash, which was discovered to posses Pozzolanic properties.the ordinary Portland cement was replaced by neem ash by 5%,10%,15%,20% and 25% by weight also flash replaced by 15%,20%,25% and 30% the cubes were crushed to know the comparative strength of the concrete at different curing days. The last result showed that workability and strength properties of the concrete was depended on water cement ratio, total days of curing, the percentage of replacement of Neem leaves ash for OPC . I. This project it was noticed that the result of 5% NLA and 15% fly ash and 10% NLA and 20% of fly ash were gradually increasing the strength at 28 days. Neem leaves play a vital role and behaviour of Neem leaves ash and flash used concrete will be studied

Influence of Fly Ash and Basalt Fibers on Strength and Chloride Penetration Resistance of Self-Consolidating Concrete

2016 ◽  
Vol 866 ◽  
pp. 3-8 ◽  
Author(s):  
Osama Ahmed Mohamed ◽  
Waddah Al Hawat
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Strength Properties ◽  
Chloride Penetration ◽  
Partial Replacement ◽  
Basalt Fibers ◽  
Self Consolidating Concrete ◽  
Chloride Penetration Resistance ◽  
Hardened Properties

Fly ash is a sustainable partial replacement of Portland cement that offers significant advantages in terms of fresh and hardened properties of concrete. This paper presents the findings of a study that aims at assessing the durability and strength properties of sustainable self-consolidating concrete (SCC) mixes in which Portland cement was partially replaced with 10%, 20%, 30%, and 40% fly ash. The study confirms that replacing Portland cement with fly ash at all of the percentages studied improves resistance of concrete to chloride penetration. The 40% fly ash mix exhibited the highest resistance to chloride penetration compared to the control mix. Despite the relative drop in compressive strength after 7 days of curing, the 28-day compressive strength of 40% SCC mix reached 55.75 MP, which is very close to the control mix. The study also confirms that adding 1%, 1.5%, and 2% basalt fibers, respectively, to the 40% fly ash mix improves the resistance to chloride penetration compared to the mix without basalt fibers.

Influence of Physicochemical Properties of Sugarcane Bagasse Ash (SCBA) in Portland Cement Hydration

2018 ◽  
Vol 765 ◽  
pp. 324-328
Author(s):  
Tiago Assunção Santos ◽  
José da Silva Andrade Neto ◽  
Vitor Souza Santos ◽  
Daniel Véras Ribeiro
Keyword(s):  
Portland Cement ◽  
Sugarcane Bagasse ◽  
Cement Hydration ◽  
New Technologies ◽  
Pozzolanic Reaction ◽  
Cement Industry ◽  
Partial Replacement ◽  
Cement Pastes ◽  
Sugarcane Bagasse Ash ◽  
Portland Cement Hydration

Due to the concern with the environmental impacts caused by the gases emitted by the cement industry and by the inadequate disposal of wastes generated in the sugar-alcohol industry, such as sugarcane bagasse ash (SCBA), a search for the development of new technologies, which are less aggressive to the environment and that propose feasible alternatives, began in order to reuse these wastes properly. Among these alternatives is the reuse of SCBA as partial replacement to cement or as addition to cementitious matrices. In this way, the present research has the objective of analyzing the influence of SCBA obtained by the calcination of sugarcane bagasse (SCB), at 600°C, in the process of Portland cement hydration. Initially, the SCBA was characterized physically, chemically and mineralogically, and then cement pastes with 20% and 35% substitution contents were elaborated, besides the reference paste, which were analyzed through X-ray diffraction (XRD) and thermogravimetric (TG) techniques. The results obtained show that there is a consumption of portlandite as a consequence of the use of SCBA, evidencing the pozolanicity of these ashes. In the pastes with 35% substitution content, there was an intense consumption of the portlandite, indicating, in this proportion, the pozzolanic reaction was more intense.

scholarly journals Effect of Elevated Temperature on Alkali Activated Slag and Fly Ash based Geopolymer Concrete

2020 ◽  
Vol 9 (4) ◽  
pp. 1241-1250
Keyword(s):  
Compressive Strength ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Flexural Strength ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Geopolymer Concrete ◽  
Base Materials ◽  
Activated Slag ◽  
Alkali Activated

Activated Slag (AAS) and Fly Ash (FA) based geopolymer concrete a new blended alkali-activated concrete that has been progressively studied over the past years because of its environmental benefits superior engineering properties. Geopolymer has many favorable characteristics in comparison to Ordinary Portland Cement. Many base materials could be utilized to make geopolymer with the convenient concentration of activator solution. In this study, the experimental program composed of two phases; phase on divided into four groups; Group one deliberated the effect of sodium hydroxide molarity and different curing condition on compressive strength. Group two studied the effect of alkali activated solution (NaOH and Na2SiO3) content on compressive strength and workability. The effect of sand replacement with slag on compressive strength and workability was explained in group three. Group four studied the effect of slag replacement with several base materials Fly Ash (FA), Ordinary Portland Cement (OPC), pulverized Red Brick (PRB), and Meta Kaolin (MK). Phase two contains three mixtures from phase one which had the highest compressive strength. For each mixture, the fresh concrete test was air content. In addition the hardened concrete tests were the compressive strength at 3, 7, 28, 90, 180, and 365 days, the flexural strength at 28, 90, and 365 days, and the young's modulus at 28, 90, and 365 days. Moreover; the three mixtures were exposed to elevated temperature at 100oC, 300oC, and 600oC to study the effect of elevated temperature on compressive and flexural strength.

scholarly journals A Low-Autogenous-Shrinkage Alkali-Activated Slag and Fly Ash Concrete

2020 ◽  
Vol 10 (17) ◽  
pp. 6092
Author(s):  
Zhenming Li ◽  
Xingliang Yao ◽  
Yun Chen ◽  
Tianshi Lu ◽  
Guang Ye
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
High Performance ◽  
Structural Engineering ◽  
Autogenous Shrinkage ◽  
Portland Cement Concrete ◽  
Alkali Activated Slag ◽  
Cracking Potential ◽  
Activated Slag ◽  
Alkali Activated

Alkali-activated slag and fly ash (AASF) materials are emerging as promising alternatives to conventional Portland cement. Despite the superior mechanical properties of AASF materials, they are known to show large autogenous shrinkage, which hinders the wide application of these eco-friendly materials in infrastructure. To mitigate the autogenous shrinkage of AASF, two innovative autogenous-shrinkage-mitigating admixtures, superabsorbent polymers (SAPs) and metakaolin (MK), are applied in this study. The results show that the incorporation of SAPs and MK significantly mitigates autogenous shrinkage and cracking potential of AASF paste and concrete. Moreover, the AASF concrete with SAPs and MK shows enhanced workability and tensile strength-to-compressive strength ratios. These results indicate that SAPs and MK are promising admixtures to make AASF concrete a high-performance alternative to Portland cement concrete in structural engineering.

scholarly journals Utilization of Fly Ash and Iron Slag in Concrete - An Experimental Study

2018 ◽  
Vol 7 (3.12) ◽  
pp. 235
Author(s):  
Cherukuru Surendra ◽  
Karthik S ◽  
Saravana Raja Mohan K
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Steel Slag ◽  
Cement Industry ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Conventional Concrete ◽  
Waste Products ◽  
Iron Slag ◽  
Strength Tests

The cement industry is responsible for about 6% of all CO2 emissions in the environment and numerous waste products out from the industries which is generating a lots of dumping problems and global warming. The main aim of this present study is to experimentally study the influence of partial replacement of cement with fly ash (FA) and partial replacement of fine aggregate with iron slag (IS) on the mechanical properties of concrete. Totally 10 mixes were prepared with 10, 20 and 30% replacements level of cement with fly ash and fine aggregate is replaced with 10, 20 and 30% by steel slag. The compressive and splitting tensile strength tests were found out after 7, 14, 28 and 7, 28 days age of curing for all the mixes respectively. Results were compared with conventional concrete and the optimum replacement percentage of FA and IS has reported.

Preliminary Study of the Use of a Secondary Lead Smelting Slag as an Addition to Portland Cement

2018 ◽  
Vol 761 ◽  
pp. 175-180 ◽  
Author(s):  
Janneth Torres Agredo ◽  
Sergio Gallego Restrepo ◽  
Fernando Álvarez Hincapié ◽  
Daniela Giraldo Alzate
Keyword(s):  
Portland Cement ◽  
Pozzolanic Activity ◽  
Hydration Process ◽  
Partial Replacement ◽  
Curing Time ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lead Smelting ◽  
Smelting Slag ◽  
Preliminary Study

In this work, the preliminary study about the use of secondary lead smelting slag (SLSS) as an addition to Portland cement is presented. SLSS is a waste from a Colombian secondary lead smelter. The chemical, physical and mineralogical characteristics of the raw materials were evaluated by X-ray fluorescence, particle size and X-ray diffraction. To assess the SLSS pozzolanic activity, the ASTM C618 standards were used. Additionally, cement pastes added with SLSS as Portland cement replacement in proportions of 0, 5, 10, 20 and 30% were prepared, to study the hydration process at 7, 14 and 28 of curing times. To determine the hydration products the technique of X-ray diffraction was used. Furthermore, the environmental test TCLP (Toxicity Characteristic Leaching Procedure) was performed in pastes with 28 days of curing time. Results showed that SLSS reported an index of pozzolanic activity of 87%, this value meets the standard (greater than 75%). The hydration process showed that since early curing time the waste presented a good reactivity. TCLP results satisfied the environmental standards. The outcomes showed that this waste could be used as a partial replacement of Portland cement.

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