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Book ChapterDOI

A Study on Strength Properties and Cost Analysis of Industrial Byproduct-Based Ternary Blended Geopolymer Concrete

01 Jan 2020-pp 95-106
Abstract: Flyash, ground granulated blast-furnace slag (GGBFS) and Alccofine are industrial byproduct materials and require large area of land for the safe disposal. These byproducts which are rich in alumina and silica can be value added, by using as binder in geopolymer concrete. The industrial byproducts are activated by NaOH- or KOH-based alkaline solution. Effective utilization of industrial byproducts in the construction industry will reduce the impact on the environment, which is caused due to ordinary portland cement (OPC). Previous studies on geopolymer concrete are at high molarity of NaOH and curing adopted is hot air oven curing for the effective polymerization of binder material and the alkaline activator solution (AAS). The present study is aimed to understand the effect of Alccofine as a ternary binder in geopolymer concrete at low molarities of NaOH-based alkaline solution under ambient temperature curing. Flyash, GGBFS, and Alccofine are the binder materials considered in geopolymer concrete by complete replacement of OPC. The ratio of Na2SiO3 to NaOH is fixed at 2.5 for all the geopolymer concrete mixes. Msand is used as fine aggregate by replacing with river sand in geopolymer concrete. The study also focused on comparing the compressive strength, split tensile strength, flexural strength, and cost analysis of ternary blended geopolymer concrete with conventional concrete of M30 grade. It is observed from the results that the geopolymer concrete has attained better strength properties than OPC concrete at the lesser cost and the impact on environment is reduced.
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Journal ArticleDOI
TL;DR: The study concludes that, in terms of documented global warming potential (GWP) values, 3DP technology appears to be a promising alternative to conventional construction and concrete use.
Abstract: The built environment defines humankind’s daily lives, sophistication, efficiency, and effectiveness. Despite this, its primary industry, construction—which transforms the built environment into a reality and an operation—remains in need of more efficient, innovative, and sustainable strategies, technologies, and instruments. The incorporation of digital fabrication into 3D printing (3DP) technology offers an entirely different and expanded freedom of geometry, functionality, materials, savings, efficiency, and effectiveness. For the inherent potential of 3DP technology, its sustainability assessment and potential contributions should be explored systematically to shed light on future applications and further innovations. This study presents a systematic review of the sustainability potential, assessments, and challenges of 3DP concrete for built environment applications. A comprehensive and comparative review of related literature is performed to identify the current trends and research gaps and recommend reducing or eliminating the energy and environmental footprints and the socio-economic impact. The study concludes that, in terms of documented global warming potential (GWP) values, 3DP technology appears to be a promising alternative to conventional construction and concrete use. A life cycle analysis (LCA) is recorded that is meant to be widely used as an assessment tool for environmental and energy assessment in digital fabrication technology, leaving an integrated review, including social and economic aspects, understudied. The 3DP concrete technology has unlimited potential in terms of material flexibility, savings, labour’s cost, design flexibility, and operation agility. Besides, researchers intend on introducing unconventional and locally available materials to increase the sustainability of 3DP technology in construction.

3 citations

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Journal ArticleDOI
Abstract: The alkali activation of waste materials (especially those coming from industrial and mining activities) has become an important area of research in many laboratories because it is possible to use these materials to synthesize inexpensive and ecologically sound cementlike construction materials. In the present paper, the mechanism of activation of a fly ash (no other solid material was used) with highly alkaline solutions is described. These solutions, made with NaOH, KOH, water glass, etc., have the common characteristic of having a very high OH 2 concentration. The product of the reaction is an amorphous aluminosilicate gel having a structure similar to that of zeolitic precursors. Temperature and time of curing of specimens together with the solution/fly ash ratio are some of the variables that were studied. These variables have been shown to notably influence the development of the mechanical strength of the final product. Mechanical strengths with values in the 60 MPa range were obtained after curing the fly ash at 85 8 C for only 5 h. © 1999 Elsevier Science Ltd. All rights reserved.

1,493 citations

Journal ArticleDOI
01 Jun 2011-Fuel
Abstract: NaOH-activated ground fly ash geopolymers, cured at room temperature, were studied in this paper. Ground fly ash (GFA), with a median particle size of 10.5 μm, was used as source material. NaOH concentrations of 4.5–16.5 M (M) were used as an alkali activator. Compressive strength tests and microstructure observations using SEM, EDX, XRD and FTIR were performed. Results indicated that GFA gave higher strength geopolymer paste compared to original fly ash. Ground fly ash could be used as a source material for making geopolymers cured at room temperature. An increase in NaOH concentration from 4.5 to 14.0 M increased the strength of GFA geopolymer pastes. Microstructure studies indicated that NaOH concentrations of 12.0–14.0 M created new crystalline products of sodium aluminosilicate. The compressive strengths at 28 days of 20.0–23.0 MPa were obtained with the NaOH concentrations of 9.5–14.0 M. Increasing the NaOH concentration beyond this point resulted in a decrease in the strength of the paste due to early precipitation of aluminosilicate products.

576 citations

Journal ArticleDOI
Abstract: The objective of the present work is to know the joint influence of a series of factors (specific surface of the slag, curing temperature, activator concentration, and the nature of the alkaline activator) on the development of mechanical strengths in alkaline-activated slag cement mortars. To reach this aim, a factorial experimental design was carried out (a complete 2 3 × 3 1 design) for every age studied (3 to 180 days). Through the variance analysis, the most significant factor on the response turned out to be the alkaline activator nature. The activator used, Na 2 SiO 3 · nH 2 O + NaOH, was the factor that gave the highest mechanical strengths in all tests. The next most statistically significant factor was the activator concentration, followed by curing temperature, and, finally, the specific surface of the slag. The equations of the model describing the mechanical behaviour for flexural and compressive strengths and their relationships for each age studied were established

434 citations

Journal ArticleDOI
Abstract: This paper presents a study on geopolymers and geopolymer/aggregate composites made with class F fly ash. Samples were heated up to 800 °C to evaluate strength loss due to thermal damage. The geopolymers exhibited strength increases of about 53% after temperature exposure. However, geopolymer/aggregate composites with identical geopolymer binder formulations decreased in strength by up to 65% after the same exposure. Test data from dilatometry measurements of geopolymers and aggregates provides an explanation for this behavior. The tests show that the aggregates steadily expanded with temperature, reaching about 1.5–2.5% expansion at 800 °C. Correspondingly, the geopolymer matrix undergoes contraction of about 1% between 200 °C and 300 °C and a further 0.6% between 700 °C and 800 °C. This apparent incompatibility is concluded to be the cause of the observed strength loss. This study presents the results of 15 different geopolymer combinations (i.e. mixture proportions, curing and age) and four different aggregates.

336 citations

Journal ArticleDOI
Abstract: In this paper, the influence of fineness of fly ash on water demand and some of the properties of hardened mortar are examined. In addition to the original fly ash (OFA), five different fineness values of fly ash were obtained by sieving and by using an air separator. Two sieves, Nos. 200 and 325, were used to obtain two lots of graded fine fly ash. For the classification using air separator, the OFA was separated into fine, medium and coarse portions. The fly ash dosage of 40% by weight of binder was used throughout the experiment. From the tests, it was found that the compressive strength of mortar depended on the fineness of fly ash. The strength of mortar containing fine fly ash was better than that of OFA mortar at all ages with the very fine fly ash giving the highest strength. The use of all fly ashes resulted in significant improvement in drying shrinkage with the coarse fly ash showing the least improvement owing primarily to the high water to binder ratio (W/B) of the mix. Significant improvement of resistance to sulfate expansion was obtained for all fineness values except for the coarse fly ash where greater expansion was observed. The resistance to sulfuric acid attack was also improved with the incorporation of all fly ashes. In this case the coarse fly ash gave the best performance with the lowest rate of the weight loss owing probably to the better bonding of the coarse fly ash particles to the cement matrix and less hydration products. It is suggested that the fine fly ash is more reactive and its use resulted in a denser cement matrix and better mechanical properties of mortar.

331 citations

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