scholarly journals Effect of Utalization of Natural Aggregates by Rap Aggregates And Cement By GGBS in Alkali Activated Concrete Pavement

2019 ◽  
Vol 8 (3) ◽  
pp. 3813-3819
Keyword(s):  
Concrete Pavement ◽  
Geopolymer Concrete ◽  
River Sand ◽  
Rigid Pavement ◽  
Complete Replacement ◽  
Coarse Aggregates ◽  
Fine Aggregates ◽  
Natural Aggregates ◽  
Alkali Activated Concrete ◽  
Alkali Activated

Coarse aggregates and cement are the main constituents of the concrete in the rigid pavement structure. The procurement and generation of natural aggregates are getting difficult day by day because of a lack of natural resources. Search for alternatives to natural coarse and fine aggregates leads to the usage of Reclaimed Asphalt Pavement aggregates, which are produced abundantly due to the replacement of flexible pavement with the rigid pavement. Ground Granulated Blast Furnace Slag (GGBS) is a waste material/by-product from steel and iron industries that can be used as an alternative binder in the alkali enacted system in place of cement. This study is taken up to determine the physical properties of materials, strength parameters and durability aspects of alkali-activated concrete are studied with GGBS which is the complete replacement for cement. The RAP aggregates are procured from KR market flyover Bangalore. And it is checked in the effective utilization in geopolymer concrete pavements. RAP fine aggregates and RAP coarse aggregates are partially replaced with river sand and natural aggregates with a variation of 100%, 75%, 50%, and 25% for M40 grade of concrete. Na2O dosage of 4.5% and activator modulus of 1.25 is taken and kept constant throughout the study. The cubes, cylinders and beams were casted and tested for strength. And fatigue test and non destructive test such as ultrasonic pulse velocity and rebound hammer test is conducted. The results can be analyzed to identify the importance of RAP fine aggregates and RAP coarse aggregates in the geopolymer concrete pavement for its effective usage for present scenario. Concluding all the test results the replacement of 25% RAP coarse aggregates and 50% RAP fine aggregates giving more strength than normal concrete which can be used for pavement construction

scholarly journals Research on Eco-friendly Alkali Activated Concrete Incorporating Industrial Wastes

2019 ◽  
Vol 8 (9S2) ◽  
pp. 477-482
Keyword(s):  
Raw Materials ◽  
Sodium Hydroxide Solution ◽  
Industrial Wastes ◽  
Liquid Sodium ◽  
Alkali Activation ◽  
Waste Glass Powder ◽  
Fine Aggregates ◽  
Alkaline Activator ◽  
Alkali Activated Concrete ◽  
Alkali Activated

In the present scenario, the production of green and sustainable concrete has become a must to substitute the ordinary Portland cement (OPC) concrete. It is an eminent fact that the manufacture of OPC requires burning of its raw materials which lead to a huge amount of carbon dioxide liberation; thus it requires a large amount of energy dissipation. The concrete produced using alkali activation has become renowned methods to replace the conventional OPC, which gives an answer to find a way to produce environmentally friendly concrete. In the current study, the alkaline activator used to activate the binder was sodium hydroxide solution dispersed in liquid sodium silicate. The utilization of industrial dissipate materials such as GGBS, fly ash, and waste glass powder was used as the binding ingredients, and stone crusher dust was used as fine aggregates. The experimental investigation showed that a quality concrete can be easily produced using alkali activation of industrial wastes satisfying its strength requirements. The statistical models developed shown that there is a significant relationship between various cube and cylinder strengths. Thus alkali-activated concrete(AAC) can effectively reduce the environmental hazards associated with OPC concrete, which also provides an effective way of utilizing major industrial byproducts

scholarly journals Polyethylene Terephthalate (PET) Bottles Waste as Fine Aggregate in Concrete

2019 ◽  
Vol 8 (6S4) ◽  
Keyword(s):  
Natural Resources ◽  
Polyethylene Terephthalate ◽  
Construction Material ◽  
Fine Aggregate ◽  
River Sand ◽  
Recycled Pet ◽  
Pet Bottles ◽  
Fine Aggregates ◽  
New Construction ◽  
Natural Aggregates

Concrete construction industry is one of the major sector utilizing natural resources to produce concrete for building constructions. The rapid increase in building constructions and the demand for natural aggregates has resulted in depletion natural resources at an alarming rate. Uncontrolled mining activity worsens the situation. Thus serious awareness has been taken into consideration, has to be identified as a potential river sand substitution for fine aggregates replacement in concrete. For this review, utilizing recycled material are described as a fine aggregate replacement to river sand, particularly recycled Polyethylene Terephthalate (PET) bottles. Recycled PET Bottles are categorized as nonbiodegradable waste materials which are injurious to health. Recycled PET bottles in concrete are economical and help in reducing disposal problems. Recycled PET bottles are pondered as the best eco-friendly alternative not only for resolving the problem of disposal but as a new construction material for concrete

New Concrete with Recycled Aggregates from Leftover Concrete

2015 ◽  
Vol 754-755 ◽  
pp. 389-394
Author(s):  
Ofelia Corbu ◽  
Attila Puskás ◽  
Andrei Victor Sandu ◽  
Adrian M. Ioani ◽  
Kamarudin Hussin ◽  
...  
Keyword(s):  
Concrete Strength ◽  
Ecological Impact ◽  
Experimental Tests ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Concrete Aggregate ◽  
River Sand ◽  
Coarse Aggregates ◽  
Concrete Type ◽  
Natural Aggregates

We live in an era where people should be more aware of pollution and its consequences. The present paper reveals a way protecting the environment while producing high quality concrete. What make this type of concrete environmentally friendly are the recycled aggregates in the concrete composition amongst with eliminating the ecological impact by saving large amounts of natural aggregates resources. Recycling concrete comes with many other advantages that lead to waste reduction, economy in waste transportation and storage taxes, which are becoming increasingly expensive. This research is based on mix design and experimental tests carried out on C20/25 strength class concrete with uncontaminated leftover concrete aggregates (LCAgg). It reveals favorable results in order to militate for recycled concrete aggregate uses in regular concrete strength classes respectively for common structural elements, mainly for slabs. River sand (0/4 mm) and coarse aggregates (4/8 mm and 8/16 mm): natural sources or recycled concrete type-alternatively used in several mixes-were utilized in concrete mixes.

scholarly journals GGBS based alkali activated fine aggregate in concrete - Properties at fresh and hardened state

2021 ◽  
Vol 13 (1) ◽  
pp. 47-53
Author(s):  
G. Lizia Thankam ◽  
T.R. Neelakantan ◽  
S. Christopher Gnanaraj
Keyword(s):  
Mechanical Properties ◽  
Alkaline Solution ◽  
Elevated Temperatures ◽  
Fresh Concrete ◽  
Hardened Concrete ◽  
Fine Aggregate ◽  
River Sand ◽  
Complete Replacement ◽  
Concrete Properties ◽  
Fine Aggregates

Abstract Scarcity of the construction materials, peculiarly the natural river sand has become a serious threat in the construction industry. Though many researchers of developed and developing countries are trying to find alternative sources for the same, the complete replacement of the fine aggregate in concrete is crucial. Geopolymer sand developed from the Industrial waste (Ground granulated blast furnace slag - GGBS) is an effective alternative for the complete replacement of the natural sand. The GGBS based geopolymer sand (G-GFA) was tested for physical and chemical properties. Upon the successful achievement of the properties in par with the natural river sand, the fresh properties (fresh concrete density & slump) and hardened properties (compressive strength, tensile strength & flexural strength) of the concrete specimens developed with G-GFA were studied. The G-GFA is obtained by both air drying (AD-G-GFA) and oven drying (OD-F-GFA) after the dry mixing of the alkaline solution and GGBS for about 10 min. Thus, developed fine aggregates were studied separately for the fresh and hardened concrete to optimize the feasible one. Superplasticizer of 0.4% is included in the concrete mix to compensate the sightly hydrophilic nature of the fine aggregates produced. The mechanical properties of the concrete with G-GFA are observed to be more than 90% close to that of the concrete developed with natural river sand. Thus, both the fresh and mechanical properties of the G-GFA concrete specimens resulted in findings similar to those of the control specimen developed with natural river sand reflecting the plausibility of G-GFA as a complete replacement choice to the fine aggregate in the concrete industry. The flaky GGBS particles merge well with the alkaline solution at room temperature itself since the former gets dried at elevated temperatures. Thus, more feasible fresh concrete properties and mechanical properties were recorded for the AD-G-GFA than the OD-G-GFA.

scholarly journals Concrete produced with recycled aggregates

2012 ◽  
Vol 5 (5) ◽  
pp. 692-701 ◽  
Author(s):  
J. J. L. Tenório ◽  
P. C. C. Gomes ◽  
C. C. Rodrigues ◽  
T. F. F. de Alencar
Keyword(s):  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Hardened Concrete ◽  
Specific Mass ◽  
River Sand ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates ◽  
Natural Aggregates

This paper presents the analysis of the mechanical and durable properties of recycled aggregate concrete (RAC) for using in concrete. The porosity of recycled coarse aggregates is known to influence the fresh and hardened concrete properties and these properties are related to the specific mass of the recycled coarse aggregates, which directly influences the mechanical properties of the concrete. The recycled aggregates were obtained from construction and demolition wastes (CDW), which were divided into recycled sand (fine) and coarse aggregates. Besides this, a recycled coarse aggregate of a specific mass with a greater density was obtained by mixing the recycled aggregates of the CDW with the recycled aggregates of concrete wastes (CW). The concrete was produced in laboratory by combining three water-cement ratios, the ratios were used in agreement with NBR 6118 for structural concretes, with each recycled coarse aggregates and recycled sand or river sand, and the reference concrete was produced with natural aggregates. It was observed that recycled aggregates can be used in concrete with properties for structural concrete. In general, the use of recycled coarse aggregate in combination with recycled sand did not provide good results; but when the less porous was used, or the recycled coarse aggregate of a specific mass with a greater density, the properties of the concrete showed better results. Some RAC reached bigger strengths than the reference concrete.

scholarly journals Strength Development Properties Of Sugar Cane Bagasse Ash Blended Geoploymer Concrete Containing Waste Steel Fibers

2019 ◽  
Vol 8 (6) ◽  
pp. 1151-1156
Keyword(s):  
Volume Fraction ◽  
Steel Fibers ◽  
Strength Development ◽  
Geopolymer Concrete ◽  
Test Results ◽  
Split Tensile Strength ◽  
Sugar Cane Bagasse Ash ◽  
Concrete Matrix ◽  
Alkali Activated Concrete ◽  
Alkali Activated

This research paper deals the two different mixture of GGBS/SCBA have been used for preparing the geopolymer alkali-activated concrete, by using NaOH (12 M solution), sodium silicate (12 M solution in Na+ and SiO2 /Na2O molarity ratio of 0.3) and KOH (12 M solution) as activating solutions. Replacements of 10%, 20% and 30% of GGBS by SCBA were carried out for various mixes. It is observed that 20% replacement of GGBS showed better strength enhancement in the range 25-40 MPa at 3 days curing. However, the addition of waste steel fibers up to 1.5% by volume fraction (Vf) showed a reasonable improvements on the compressive strength and split tensile strength of geopolymer concrete. Further test results showed drastic improvement in flexural strength of geopolymer concrete for various mixes. The various comparative assessments were made for different geopolymer mixtures and the reinforcing effects of steel fibers were investigated in different concrete matrix.

scholarly journals Cradle-to-Gate Life Cycle and Economic Assessment of Sustainable Concrete Mixes—Alkali-Activated Concrete (AAC) and Bacterial Concrete (BC)

2021 ◽  
Vol 6 (7) ◽  
pp. 104
Author(s):  
Kruthi Kiran Ramagiri ◽  
Ravali Chintha ◽  
Radha Kiranmaye Bandlamudi ◽  
Patricia Kara De Maeijer ◽  
Arkamitra Kar
Keyword(s):  
Life Cycle ◽  
Environmental Impact ◽  
Economic Assessment ◽  
Sustainable Concrete ◽  
Coarse Aggregates ◽  
Cradle To Gate ◽  
Equivalent Strength ◽  
Alkali Activated Concrete ◽  
Alkali Activated ◽  
Bacterial Concrete

The negative environmental impacts associated with the usage of Portland cement (PC) in concrete induced intensive research into finding sustainable alternative concrete mixes to obtain “green concrete”. Since the principal aim of developing such mixes is to reduce the environmental impact, it is imperative to conduct a comprehensive life cycle assessment (LCA). This paper examines three different types of sustainable concrete mixes, viz., alkali-activated concrete (AAC) with natural coarse aggregates, AAC with recycled coarse aggregates (RCA), and bacterial concrete (BC). A detailed environmental impact assessment of AAC with natural coarse aggregates, AAC with RCA, and BC is performed through a cradle-to-gate LCA using openLCA v.1.10.3 and compared versus PC concrete (PCC) of equivalent strength. The results show that transportation and sodium silicate in AAC mixes and PC in BC mixes contribute the most to the environmental impact. The global warming potential (GWP) of PCC is 1.4–2 times higher than other mixes. Bacterial concrete without nutrients had the lowest environmental impact of all the evaluated mixes on all damage categories, both at the midpoint (except GWP) and endpoint assessment levels. AAC and BC mixes are more expensive than PCC by 98.8–159.1% and 21.8–54.3%, respectively.

scholarly journals Flexural Fatigue performance of Alkali Activated Slag Concrete mixes incorporating Copper Slag as Fine Aggregate

2015 ◽  
Vol 10 (1) ◽  
pp. 7-18 ◽  
Author(s):  
B.M. Mithun ◽  
M.C. Narasimhan ◽  
Palankar Nitendra ◽  
A.U. Ravishankar
Keyword(s):  
Mechanical Properties ◽  
Plain Concrete ◽  
Copper Slag ◽  
Fatigue Performance ◽  
Fine Aggregate ◽  
River Sand ◽  
Alkali Activated Slag ◽  
Fine Aggregates ◽  
Activated Slag ◽  
Alkali Activated

Abstract The present investigation attempts a detailed study of mechanical properties and fatigue characteristics of a new class of Alkali Activated Slag Concrete (AASC) mixes incorporating Copper Slag (CS) as fine aggregates. The natural river sand is replaced with Copper Slag, upto 100% (by volume) as fine aggregate in these AASC mixes. The behavior of plain concrete prisms, cast with this range of AASC mixes under dynamic cyclic loads with sand/CS fine aggregates is studied and is compared with conventional OPC-based concrete specimens. The results indicate that incorporation of CS even upto 100% as fine aggregates, did not have any adverse effects on the mechanical properties of AASC mixes. The AASC mixes with CS displayed slightly better fatigue performance as compared to AASC mix with river sand. An attempt is also made herein to statistically describe the fatigue life data of AASC mixes using a 2-parameter Weibull distribution.

scholarly journals Preparation and Properties of Alkali Activated Coarse Aggregates Using Fly Ash and Slag

2021 ◽  
Author(s):  
Rugma Sunil ◽  
Parvathy Panicker L ◽  
R. Megha ◽  
Athira K. Vijayan ◽  
Ramaswamy K. P
Keyword(s):  
Fly Ash ◽  
Chemical Activation ◽  
Industrial Wastes ◽  
Alkali Activation ◽  
Equal Proportion ◽  
Coarse Aggregates ◽  
Concrete Production ◽  
Naoh Solution ◽  
Natural Aggregates ◽  
Alkali Activated

Coarse aggregate is an essential component of concrete which influences the properties of concrete. Generally, natural crushed stones are being used for the concrete production. The increased demand of aggregates for concrete production can be countered by using alternate aggregates. Production of artificial aggregates from industrial wastes appear as a promising and sustainable alternative to natural aggregates as it helps in utilizing large amount of industrial byproducts in concrete, reduces environmental pollution and also relieves the issues involved in their waste disposal. Hence, this study aims at the utilization of industrial wastes (fly ash and slag) for the manufacture of synthetic aggregates which could be a potential sustainable alternative for the coarse aggregates. Cold bonded pelletized aggregates were prepared by using alkali-activated Class F fly ash and ground granulated blast furnace slag. Alkali mixture of sodium silicate (Na2SiO3) and 10M sodium hydroxide (NaOH) solution were used for the chemical activation of fly ash and slag. Two types of synthetic aggregates were prepared using the fabricated disc pelletizer; mix containing only slag and another mix with equal proportion of fly ash and slag, and the aggregates were heat cured for 24 hours. Tests were done to determine properties such as aggregate surface texture and shape, particle size distribution, bulk density and specific gravity, and the results were compared with the properties of normal aggregates (natural crushed stones). The results indicate that synthetic aggregates made by alkali activation of fly ash and slag could be a potential alternative to the crushed stones.

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