Flexural Performance of Geopolymer Concrete Modified with Pozzalonic Minerals and Secondary Reinforcement

2018 ◽  
Vol 15 (2) ◽  
pp. 459-469
Author(s):  
D. R. Anand Rejilin ◽  
R. Murugesan ◽  
V. Bravin Ebanesh
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Secondary Reinforcement ◽  
Fibre Reinforcement ◽  
Percentage Increase ◽  
Cement Concrete ◽  
Flexural Performance ◽  
Micro Cracks ◽  
Structural Applications

Concrete, the versatile building material is relevantly used for structural applications for its ease of application and in situ adaptability. Decline of raw materials, cost and environmental issues related to unsustainable usage of cement, persuades the construction industries for an alternate binder similar to cement. Geoploymer concrete known for its eco-friendly manufacturing process and economic approach makes the, GPC a viable substitute for cement concrete. At elevated temperature, GPC undergoes polymerisation reaction and develops three dimensional amorphous components which exhibits enriched mechanical properties. To achieve the in-situ application of geoploymer concrete and to overcome the requirement of heat during polymerisation reaction, fly ash based GPC was modified with different proportions of GGBS and OPC and curing it with ambient temperature for enhancing its mechanical behaviour. Variation in temperature during the initial stages of casting process produces micro cracks which are prevented by addition of Secondary reinforcements which furthermore improved the mechanical properties. A constant percentage of GUJCON fiber as secondary reinforcement was added to all the modified proportions. The fly ash based GPC replaced with GGBS and OPC showed improved split and compressive strength at 100% and 40%. Further improvement of strength was observed with 12% replacement of GGBS with OPC to GGBS based GPC. The flexural performance of the modified GPC with optimum proportions of GGBS and OPC was compared with conventional cement concrete beam. The percentage increase in strength of GGBS based GPC with optimum OPC content when compared with conventional specimens showed 53% improvement in strength. When fibre reinforcement was added in prescribed quantity, it promoted the mechanical strength and reduced micro cracks by which the load carrying capacity was increased to 66%. The structural performance of modified GPC was found to be suitable for in situ applications in ambient curing condition.

scholarly journals Mechanical Properties of High-Volume Fly Ash Strain Hardening Cementitious Composite (HVFA-SHCC) for Structural Application

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2607 ◽  
Author(s):  
Chenhua Jin ◽  
Chang Wu ◽  
Chengcheng Feng ◽  
Qingfang Zhang ◽  
Ziheng Shangguan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Strain Hardening ◽  
Construction Material ◽  
High Volume ◽  
Partial Replacement ◽  
Cementitious Composite ◽  
Multiple Cracking ◽  
High Volume Fly Ash ◽  
Structural Applications

Strain-hardening cementitious composite (SHCC) is a kind of construction material that exhibits multiple cracking and strain-hardening behaviors. The partial replacement of cement with fly ash is beneficial to the formation of the tensile strain-hardening property of SHCC, the increase of environmental greenness, and the decrease of hydration heat, as well as the material cost. This study aimed to develop a sustainable construction material using a high dosage of fly ash (no less than 70% of the binder material by weight). Based on the micromechanics analysis and particle size distribution (PSD) optimization, six mixes with different fly ash to cement ratios (2.4–4.4) were designed. The mechanical properties of the developed high-volume fly ash SHCCs (HVFA-SHCCs) were investigated through tensile tests, compressive tests, and flexural tests. Test results showed that all specimens exhibited multiple cracking and strain-hardening behaviors under tension or bending, and the compressive strength of the designed mixes exceeded 30MPa at 28 days, which is suitable for structural applications. Fly ash proved to be beneficial in the improvement of tensile and flexural ductility, but an extremely high volume of fly ash can provide only limited improvement. The HVFA-SHCC mix FA3.2 (with fly ash to binder ratio of about 76% by weight) designed in this study is suggested for structural applications.

Comparative Investigations of some Properties Related to Durability of Cement Concretes Containing Different Fly Ashes

2014 ◽  
Vol 1054 ◽  
pp. 154-161 ◽  
Author(s):  
Wojciech Kubissa ◽  
Barbara Pacewska ◽  
Iwona Wilińska
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Low Permeability ◽  
Concrete Durability ◽  
Cement Concrete ◽  
Fly Ashes ◽  
Chloride Migration ◽  
Good Workability

The results of research of mechanical properties and selected other characteristics influencing durability of cement concretes containing cement substitutes were presented. Cement concretes performed with conventional fly ash, fluidised fly ash and their mixture were investigated. The obtained results were compared with findings registered for two types of concrete performed without cement replacements and with cement concrete containing silica fume. The results have shown that cement concrete with predetermined 28-day compressive strength of about 50 MPa and good workability may be obtained using different cement replacements. Generally, these cement concretes exhibited also favorable properties related to concrete durability, i.e. low permeability and sorptivity, and significant reduction of chloride migration coefficient. Favourable results were obtained for cement concrete containing mix of conventional and fluidised fly ashes: good workability, compressive strength after 28th day exceeding 50 MPa, low permeability of water, and low sorptivity, as well as low coefficient of chloride migration. These features were similar as for cement concrete containing silica fume.

scholarly journals Hybrid Fly Ash-Based Geopolymeric Foams: Microstructural, Thermal and Mechanical Properties

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2919 ◽  
Author(s):  
Giuseppina Roviello ◽  
Laura Ricciotti ◽  
Antonio Jacopo Molino ◽  
Costantino Menna ◽  
Claudio Ferone ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Circular Economy ◽  
Coal Fly Ash ◽  
Silicate Solution ◽  
Thermal And Mechanical Properties ◽  
Blowing Agent ◽  
Materials Used

This research investigates the preparation and characterization of new organic–inorganic geopolymeric foams obtained by simultaneously reacting coal fly ash and an alkali silicate solution with polysiloxane oligomers. Foaming was realized in situ using Si0 as a blowing agent. Samples with density ranging from 0.3 to 0.7 g/cm3 that show good mechanical properties (with compressive strength up to ≈5 MPa for a density of 0.7 g/cm3) along with thermal performances (λ = 0.145 ± 0.001 W/m·K for the foamed sample with density 0.330 g/cm3) comparable to commercial lightweight materials used in the field of thermal insulation were prepared. Since these foams were obtained by valorizing waste byproducts, they could be considered as low environmental impact materials and, hence, with promising perspectives towards the circular economy.

Studies of Mechanical Properties of Multiwall Nanotube Based Polymer Composites

2014 ◽  
Vol 5 (3) ◽  
Author(s):  
A. K. Gupta ◽  
S. P. Harsha
Keyword(s):  
Mechanical Properties ◽  
Polymer Composites ◽  
Composite Structures ◽  
Secondary Reinforcement ◽  
Chemical Vapor ◽  
Carbon Composite ◽  
Diglycidyl Ether ◽  
Two Phase ◽  
Three Phase ◽  
Structural Applications

The two phase polymer composites have been extensively used in various structural applications; however, there is need to further enhance the strength and stiffness of these polymer composites. Carbon nanotubes (CNTs) can be effectively used as secondary reinforcement material in polymer based composites due to their superlative mechanical properties. In this paper, effects of multiwall nanotubes (MWNTs) reinforcement on epoxy–carbon polymer composites are investigated using experiments. MWNTs synthesized by chemical vapor deposition (CVD) technique and amino-functionalization are achieved through acid-thionyl chloride route. Diglycidyl ether of bisphenol-A (DGEBA) epoxy resin with diethyl toluene diamine (DETDA) hardener has been used as matrix. T-300 carbon fabric is used as the primary reinforcement. Three types of test specimen of epoxy–carbon composite are prepared with MWNT reinforcement as 0%, 1%, and 2% MWNT (by weight). The resultant three phase nanocomposites are subjected to tensile test. It has been found that both tensile strength and strain at failure are substantially enhanced with the small addition of MWNT. The analytical results obtained from rule of mixture theory (ROM) shows good agreement with the experimental results. The proposed three phase polymer nanocomposites can find applications in composite structures, ballistic missiles, unmanned arial vehicles, helicopters, and aircrafts.

Comparative Investigations of some Properties of Lightweight Cement Concretes Containing Siliceous Fly Ash

2016 ◽  
Vol 677 ◽  
pp. 67-74
Author(s):  
Wojciech Kubissa
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fly Ash ◽  
Chloride Ion ◽  
Lightweight Aggregate ◽  
Cement Concrete ◽  
Carbonation Depth ◽  
Ion Migration ◽  
Durability Of Concrete ◽  
Class F

In the article the possibility of lightweight cement concrete manufacturing has been presented with use of binder in which part of cement was replaced with siliceous fly ash Class F. It was used lightweight aggregate Pollytag and Keramzyt. Total amount of binder was 400 kg/m3 with w/b=0.5. Mechanical properties has been tested as well as properties affecting durability of concrete. Replacing part of cement with fly ash improved concrete resistance on chloride ion migration, reduced compressive and tensile strength of concrete and increased carbonation depth.

Improvement in mechanical properties of SBR/Fly ash composites by in-situ grafting-neutralization reaction

2018 ◽  
Vol 354 ◽  
pp. 849-855 ◽  
Author(s):  
Shuyan Yang ◽  
Ping Liang ◽  
Xiaokang Peng ◽  
Yanxue Zhou ◽  
Kaihui Hua ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Neutralization Reaction

Microstructures and Mechanical Properties of NiAl+Mo In-Situ Eutectic Composites

1990 ◽  
Vol 194 ◽  
Author(s):  
P. R. Subramanian ◽  
M. G. Mendiratta ◽  
D. B. Miracle ◽  
D. M. Dimiduk
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Room Temperature ◽  
Composite System ◽  
Elevated Temperatures ◽  
Two Phase ◽  
Structural Applications ◽  
Temperature Fracture

AbstractThe quasibinary NiAI-Mo system exhibits a large two-phase field between NiAl and the terminal (Mo) solid solution, and offers the potential for producing in-situ eutectic composites for high-temperature structural applications. The phase stability of this composite system was experimentally evaluated, following long-term exposures at elevated temperatures. Bend strengths as a function of temperature and room-temperature fracture toughness data are presented for selected NiA1-Mo alloys, together with results from fractography observations.

scholarly journals Utilization of Industrial By-Products/Waste to Manufacture Geopolymer Cement/Concrete

2021 ◽  
Vol 13 (2) ◽  
pp. 873
Author(s):  
Numanuddin M. Azad ◽  
S.M. Samindi M.K. Samarakoon
Keyword(s):  
Mechanical Properties ◽  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Industrial Waste ◽  
Cement Concrete ◽  
Granulated Blast Furnace Slag ◽  
Geopolymer Cement ◽  
Furnace Slag ◽  
By Products

There has been a significant movement in the past decades to develop alternative sustainable building material such as geopolymer cement/concrete to control CO2 emission. Industrial waste contains pozzolanic minerals that fulfil requirements to develop the sustainable material such as alumino-silicate based geopolymer. For example, industrial waste such as red mud, fly ash, GBFS/GGBS (granulated blast furnace slag/ground granulated blast furnace slag), rice husk ash (RHA), and bagasse ash consist of minerals that contribute to the manufacturing of geopolymer cement/concrete. A literature review was carried out to study the different industrial waste/by-products and their chemical composition, which is vital for producing geopolymer cement, and to discuss the mechanical properties of geopolymer cement/concrete manufactured using different industrial waste/by-products. The durability, financial benefits and sustainability aspects of geopolymer cement/concrete have been highlighted. As per the experimental results from the literature, the cited industrial waste has been successfully utilized for the synthesis of dry or wet geopolymers. The review revealed that that the use of fly ash, GBFS/GGBS and RHA in geopolymer concrete resulted high compressive strength (i.e., 50 MPa–70 MPa). For high strength (>70 MPa) achievement, most of the slag and ash-based geopolymer cement/concrete in synergy with nano processed waste have shown good mechanical properties and environmental resistant. The alkali-activated geopolymer slag, red mud and fly ash based geopolymer binders give a better durability performance compared with other industrial waste. Based on the sustainability indicators, most of the geopolymers developed using the industrial waste have a positive impact on the environment, society and economy.

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