scholarly journals Influence of Partial Replacement of Micro-Silica by Fly-Ash on Strength Properties of Reactive Powder Concrete

2020 ◽  
Vol 9 (3) ◽  
pp. 2932-2937
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Mechanical Performance ◽  
Cementitious Materials ◽  
Partial Replacement ◽  
Reactive Powder Concrete ◽  
Experimental Investigations ◽  
Reactive Powder ◽  
Micro Silica

Reactive powder concrete (RPC) is the ultra-high strength concrete made by cementitious materials like silica fumes, cement etc. The coarse aggregates are completely replaced by quartz sand. Steel fibers which are optional are added to enhance the ductility. Market survey has shown that micro-silica is not so easily available and relatively costly. Therefore an attempt is made to experimentally investigate the reduction of micro-silica content by replacing it with fly-ash and mechanical properties of modified RPC are investigated. Experimental investigations show that compressive strength decreases gradually with addition of the fly ash. With 10 per cent replacement of micro silica, the flexural and tensile strength showed 40 and 46 per cent increase in the respective strength, though the decrease in the compressive strength was observed to be about 20 per cent. For further percentage of replacement, there was substantial drop in compressive, flexural as well as tensile strength. The experimental results thereby indicates that utilisation of fly-ash as a partial replacement to micro silica up to 10 per cent in RPC is feasible and shows quite acceptable mechanical performance with the advantage of utilisation of fly-ash in replacement of micro-silica.

scholarly journals Performance of Eco Engineered Cementitious Composites Containing Supplementary Cementitious Materials as a Binder and Recycled Concrete Fines as Fine Aggregate

2021 ◽  
Vol 1200 (1) ◽  
pp. 012004
Author(s):  
M R Md Zain ◽  
C L Oh ◽  
L S Wee
Keyword(s):  
Tensile Strength ◽  
Fly Ash ◽  
Mechanical Performance ◽  
Cementitious Materials ◽  
Recycled Concrete ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Cementitious Composites ◽  
Fine Aggregate ◽  
Engineered Cementitious Composites

Abstract Engineered cementitious composites (ECC) mixtures demand a large cement content, which is detrimental to their sustainable development because mass cement production is hazardous to the environment and human health. Thus, this paper investigates the mechanical performance of eco engineered cementitious composites (ECC) under axial compressive loading and direct tensile strength tests. The eco ECC used in this investigation was comprised of cement, superplasticizer, fly ash (FA) or ground granulated blast furnace slag (GGBS), polypropylene (PP) fibre, water and recycled concrete fines (RCF). Two (2) eco ECC mixture series were designed and prepared. GGBS70 (70 percent GGBS + 30 percent cement), FA70 (70 percent Fly Ash + 30 percent cement), GGBS80 (80 percent GGBS + 20 percent cement), and FA80 (80 percent Fly Ash + 20 percent cement) are the four Cement-GGBS and Cement-Fly Ash combinations examined in this study. Also every combination had two different RCF percentages, R0.2 (0.2 percent RCF) and R0.4 (0.4 percent RCF). The main objective of this research is to determine the optimum mix design for eco ECC that contains supplementary Cementitious Materials (SCMs) such as GGBS or FA. Additionally, recycled concrete fines (RCF) were used as a substitute for sand. The influence of different cement replacement materials and RCF content on compressive and tensile strength was experimentally investigated. The inclusion of GGBS as a partial replacement of cement in the eco concrete mixture results in greater compressive strength than Fly Ash (FA). The test results revealed that increasing the RCF content in the ECC mixture resulted in higher compressive and tensile strength. When the sand to binder ratio was adjusted between 0.2 and 0.4, the compressive and tensile strength of the ECC mixture increased.

scholarly journals Effect of Fly Ash on Some Properties of Reactive Powder Concrete

2021 ◽  
Vol 27 (11) ◽  
pp. 32-46
Author(s):  
Zahraa F Muhsin ◽  
Nada Mahdi Fawzi
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Industrial Wastes ◽  
Experimental Program ◽  
Reactive Powder Concrete ◽  
Binder Ratio ◽  
Reactive Powder ◽  
Water To Binder Ratio

To achieve sustainability in the field of civil engineering, there has become a great interest in developing reactive powder concrete RPC through the use of environmentally friendly materials to reduce the release of CO2 gas produced from cement factories as well as contribute to the recycling of industrial wastes that have a great impact on environmental pollution. In this study, reactive powder concrete was prepared using total binder content of 800 kg/m3, water to binder ratio (0.275), and micro steel fibers  1% by volume of concrete. The experimental program included replacing fly ash with (8, 12, 16) % by cement weight to find the optimal ratio, which achieved the best mechanical properties of (RPC) at 7, 28, and 90 days with standard curing. Some mechanical properties of reactive powder concrete (flow, compressive strength, tensile strength, and density) were verified. The results at 28 days showed that the compressive strength (96.5) Mpa, tensile strength (9.38) Mpa, and density (2395 kg/m3). The results showed that the percentage of replacement of 8% of fly ash with cement is the optimal percentage, which achieved the highest resistance compared to the others. The results also indicated that it is possible to develop RPC using fly ash with a high withstand stress, tensile strength, and density.

scholarly journals Mechanical Testing of Composite Steel and Reactive Powder Concrete Structural Element

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3954
Author(s):  
Jan Bujnak ◽  
Peter Michalek ◽  
Frantisek Bahleda ◽  
Stefania Grzeszczyk ◽  
Aneta Matuszek-Chmurowska ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Composite Structures ◽  
Numerical Models ◽  
Concrete Slab ◽  
Initial Study ◽  
Cementitious Materials ◽  
Mechanical Tests ◽  
Reactive Powder Concrete ◽  
Structural Element ◽  
Reactive Powder

Reactive powder concrete (RPC), typically with higher compressive strength, is particularly attractive to structural engineers to apply them in infrastructures for enhancing their resistance under severe environments and loads. The main objective of the initial study presented in the paper was to investigate the behavior of two types of these new cementitious materials differing in the nature of microfibers. The RPC mixes were reinforced with steel and then with basalt microfibers. To evaluate the structural performance of developed unconventional materials, properties were investigated experimentally and compared with the control normal concrete mix. Mechanical tests indicated that dispersing fine fibers for making RPC, a mean compressive strength of 198.3 MPa and flexural strength 52.6 MPa or 23.2 MPa, respectively, were developed after 28 days of standard curing at ambient temperatures. In composite structures consisting of steel girders and a concrete slab, it is necessary to prevent the relative slip at the steel and concrete interface using shear connectors. The very high RPC strength enabled a material saving, weight-reduced application of precast construction, and particularly effective joint to steel beams. The investigation of such shear connection efficiency, in the case of the higher strength concrete deck, using standard push-out test specimens was executed. Finite element numerical models were developed. The outputs of the studies are presented in the paper.

On Effects of Fly Ash as a Partial Replacement of Cement on Concrete Strength

2012 ◽  
Vol 204-208 ◽  
pp. 3970-3973
Author(s):  
Reagan J. Case ◽  
Kai Duan ◽  
Thuraichamy G. Suntharavadivel
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Concrete Strength ◽  
Cementitious Materials ◽  
Partial Replacement ◽  
Replacement Ratio ◽  
Interface Reactions ◽  
Compressive Strength Of Concrete ◽  
Interface Bonding Strength ◽  
Large Research

As a part of a large research program aiming at the cementitious materials containing recycled materials at Central Queensland University – Australia, the current paper presents the preliminary results of a study on the effects of fly ash, which is used to replace cement in concrete, on the concrete compressive strength. For this purpose, systematic experiments have been carried out to investigate the influences of fly ash ratio and age. The compressive strength of concrete specimens with replacement ratios of 15%, 30% and 45%, and aged 7 and 28 days are measured and are compared with those of the concrete specimens without fly ash at the same ages. The results demonstrate that the strength of fly ash containing concrete improves more slowly but more strongly with aging, than their fly ash free counterparts, and an optimum fly ash replacement ratio exists where the maximum compressive strength of fly ash containing concrete can be achieved, and the maximum strength for the specimens aged 28 days and above is higher that of fly ash free concrete. Furthermore, the observation strength behaviours are analysed and discussed in terms of the influences of fly ash on interface reactions and interface bonding strength.

scholarly journals Experimental Behaviour of Fiber Reinforced Reactive Powder Concrete

2019 ◽  
Vol 9 (1S3) ◽  
pp. 454-459 ◽  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Polypropylene Fiber ◽  
Chloride Diffusion ◽  
Sisal Fiber ◽  
Reactive Powder Concrete ◽  
Coir Fiber ◽  
Split Tensile Strength ◽  
Reactive Powder

In this paper various mix proportions of Reactive Powder Concretes were formulated using ordinary Portland cement, Fly ash, Micro silica, Silica Fume, Quartz powder etc and these concretes were subjected to strength test. The best mix was selected for further in depth study with fibers like Sisal fiber, Coir fiber, Hair fiber and Polypropylene fiber mixed Reactive Powder Concrete and the various tests have been performed Cube Compressive strength, Cylinder Compressive strength, Flexural strength, Split Tensile strength, Shear test, Water absorption, Sorptivity and Chloride diffusion etc. As a result, fiber incorporated concrete shows increasing Flexural strength, splitting tensile strength, and shear strength up to 30% as compared to control RPC and gives minimal decrease in compressive strength by the addition of fibers. These characteristics make it as a promising material for casting non structural elements such as pressure pipes, flooring tiles, Partition panels, door and window frames. It can also be used as repair materials.

scholarly journals The Synergy between Bio-Aggregates and Industrial Waste in a Sustainable Cement Based Composite

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6158
Author(s):  
Cătălina Mihaela Grădinaru ◽  
Adrian Alexandru Șerbănoiu ◽  
Radu Muntean ◽  
Bogdan Vasile Șerbănoiu
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Splitting Tensile Strength ◽  
Partial Replacement ◽  
Cement Matrix ◽  
Freeze Thaw ◽  
Corn Cobs ◽  
Study Results ◽  
Sunflower Stalks

The effects of the fly ash and of the sunflower stalks and corn cobs within a cement-matrix composite were studied under the aspects of density, compressive strength, splitting tensile strength, elasticity modulus, and resistance to repeated freeze-thaw cycles. In the research were developed 20 recipes of cement-based composite, including the reference composite. Fly ash was used as partial cement replacement (10, 20 and 30% by volume), and the vegetal aggregates made by corn cobs and sunflower stalks as partial replacement of the mineral aggregates (25 and 50% by volume). The study results revealed that a lightweight composite can be obtained with 50% of vegetal aggregates, and the fly ash, no matter its percentage, enhanced the compressive strength and splitting tensile strength of the compositions with 50% of sunflower aggregates and the freeze-thaw resistance of all compositions with sunflower stalks.

scholarly journals Strength and abrasion performance of recycled aggregate based geopolymer concrete

2021 ◽  
Author(s):  
Asfaw Mekonnen LAKEW ◽  
Mukhallad M. AL-MASHHADANI ◽  
Orhan CANPOLAT
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Coarse Aggregate ◽  
Steel Fiber ◽  
Splitting Tensile Strength ◽  
Partial Replacement ◽  
Geopolymer Concrete ◽  
Recycled Coarse Aggregate ◽  
One Year

This experimental work evaluated geopolymer concrete containing fly ash and slag by partial replacement of natural coarse aggregate (NCA) with recycled coarse aggregate (RCA) to manufacture environmental-friendly concrete. The proportion of recycled aggregates considered consists of 10%, 20%, 30%, and 40% of the total coarse aggregate amount. Also, a steel fiber ratio of 0.3% was utilized. The mechanical properties and abrasion resistance of fly ash/slag-based geopolymer concrete were then assessed. Majorly, the mechanical strength of the concrete samples decreased by the increase of RCA content. The geopolymer concrete with 40% RCA gave 28.3% lesser compressive strength and 24% lower splitting tensile strength than NCA concrete at one year. Also, the flexural strength of concrete specimens was reduced by 35% (from 5.34MPa to 3.5MPa) with the incorporation of 40% RCA. The incorporation of 30% RCA caused 23% and 22.6% reduction in compressive strength at 56 days and one year, respectively. The flexural and splitting tensile strength of the specimens was not significantly reduced (less than 10%) with the inclusion of a recycled coarse aggregate ratio of up to 30%. Furthermore, the abrasion wear thickness of every concrete sample was less than 1mm. RCA inclusion of 20% produced either insignificant reduction or better strength results compared to reference mixtures. As a result, it was considered that the combination of 0.3% steel fiber and 20% recycled coarse aggregate in fly ash/slag-based geopolymer concrete leads to an eco-friendly concrete mix with acceptable short and long-term engineering properties that would lead to sustainability in concrete production and utilization sector.

Mechanical Properties of Reactive Powder Concrete Containing Fly Ash under Different Curing Regimes

2014 ◽  
Vol 597 ◽  
pp. 320-323 ◽  
Author(s):  
De Hong Wang ◽  
Yan Zhong Ju ◽  
Wen Zhong Zheng
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Ash Content ◽  
Reactive Powder Concrete ◽  
Steam Curing ◽  
Cement Ratio ◽  
Reactive Powder ◽  
Curing Regimes

Mechanical properties of reactive powder concrete (RPC) containing fly ash were investigated under different curing regimes (standard and steam curing) in this study. The experimental results indicate that, flexural strength of RPC increased considerably after steam curing, compared to the standard curing. Steam curing had no significant effect on compressive strength of RPC. Increasing the fly ash content improved the flexural strength of RPC under all curing regimes considerably. The compressive strength reached a maximum (103.8MPa) when the fly to ash and cement ratio is 0.3.

Study on Low-Cost Reactive Powder Concrete and its Application

2009 ◽  
Vol 405-406 ◽  
pp. 62-68
Author(s):  
Ming Zhang ◽  
Feng Xing ◽  
Liang Peng Deng ◽  
Zheng Liang Cao ◽  
Zhan Huang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Quartz Sand ◽  
Large Scale ◽  
Low Cost ◽  
Reactive Powder Concrete ◽  
Fine Aggregate ◽  
Complex Procedure ◽  
Reactive Powder ◽  
Very High

Reactive powder concrete (RPC) is a new kind of material with very high mechanical behavior and durability, however, high cost and complex procedure to make RPC result in hardly apply to engineering in large scale. a new low-cost RPC that compressive strength exceeds 130MPa was prepared with the replacement of quartz sand, crushed quartz and partial of silica fume by fly ash, slag and natural fine aggregate in the paper. Manhole cover that made from the low-cost RPC can meets the requirements of different situations, such as special road, motorway, etc.

scholarly journals Utilization of Rice Husk Ash in Reactive Powder Concrete

2019 ◽  
Vol 8 (4S2) ◽  
pp. 82-86
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Curing Temperature ◽  
Partial Replacement ◽  
High Price ◽  
Reactive Powder Concrete ◽  
Durability Properties ◽  
Reactive Powder

Reactive Powder Concrete (RPC) is a special concrete with excellent mechanical and durability properties and it is differentiated with other forms of concrete in terms of production, mix proportion etc. Depending upon various parameters like composition and the curing temperature, its compressive strength ranges from 130 MPa to 750 MPa, bending strength varies as 29 to 51 MPa and Young's modulus results upto 50GPa to 75GPa.Though RPC possesses many outstanding properties, it has limited applications in the construction field. The usage of higher quantity of cement and Silica Fume causes the rise of production of RPC. In addition to that, the silica fume availability is also restricted. For a country like India, usage of SF is limited due to its high price. Also, mineral admixtures can be used as a suitable alternative. Hence in this research work, Rice Husk Ash (RHA) is used as a possible alternatives for replacing silica fume in RPC. RHA holds maximum amount of silica (approx. 96%) in amorphous form. In this research, an experimental research on mechanical and durability properties of RPC by partially replacing SF with RHA. The detailed literature survey on constituent materials, mix proportions and curing conditions of RPC were done. Also, the optimum temperature and duration for the thermal treatment of RHA were identified. The compressive strength of the specimens of partial replacement of Silica Fume using RHA were tested and the results were compared with control specimens compressive strength.

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