Recycling of aggregate micro fines as a partial replacement for fly ash in 3D printing cementitious materials

2022 ◽  
Vol 321 ◽  
pp. 126372
Author(s):  
Huashan Yang ◽  
Yujun Che
Keyword(s):  
Fly Ash ◽  
3D Printing ◽  
Cementitious Materials ◽  
Partial Replacement ◽  
Micro Fines

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.

The Effect of Homogenization Procedure on Mechanical Properties of High-Performance Concrete with Partial Replacement of Cement by Supplementary Cementitious Materials

2019 ◽  
Vol 292 ◽  
pp. 102-107 ◽  
Author(s):  
Josef Fládr ◽  
Petr Bílý ◽  
Karel Šeps ◽  
Roman Chylík ◽  
Vladimír Hrbek
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Water Content ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Depth Of Penetration ◽  
Cement Additive

High-performance concrete is a very specific type of concrete. Its production is sensitive to both the quality of compounds used and the order of addition of particular compounds during the homogenization process. The mechanical properties were observed for four dosing procedures of each of the three tested concrete mixtures. The four dosing procedures were identical for the three mixes. The three mixes varied only in the type of supplementary cementitious material used and in water content. The water content difference was caused by variable k-value of particular additives. The water-to-binder ratio was kept constant for all the concretes. The additives used were metakaolin, fly ash and microsilica. The comparison of particular dosing procedures was carried out on the values of basic mechanical properties of concrete. The paper compares compressive strength and depth of penetration of water under pressure. Besides the comparsion of macro-mechanical properties, the effect of microsilica and fly ash additives on micro-mechanical properties was observed with the use of scanning electron microscopy (SEM) and nanoindentation data analysis. Nanoindentation was used to determine the thickness and strength of interfacial transition zone (ITZ) for different sequence of addition of cement, additive and aggregate. The thickness obtained by nanoindentation was further investigated by SEM EDS line scanning.

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 Mechanical and Durability Properties of Fly Ash Based Concrete Exposed to Marine Environment

2017 ◽  
Vol 12 (1) ◽  
pp. 7-18 ◽  
Author(s):  
Sarfaraz Ahmed Kagadgar ◽  
Suman Saha ◽  
C. Rajasekaran
Keyword(s):  
Fly Ash ◽  
Corrosion Current ◽  
Cementitious Materials ◽  
Mineral Admixtures ◽  
Partial Replacement ◽  
Durability Test ◽  
Curing Conditions ◽  
Durability Properties ◽  
Lower Permeability ◽  
Strength And Durability

Abstract Efforts over the past few years for improving the performance of concrete suggest that cement replacement with mineral admixtures can enhance the strength and durability of concrete. Feasibility of producing good quality concrete by using alccofine and fly ash replacements is investigated and also the potential benefits from their incorporation were looked into. In this study, an attempt has been made to assess the performance of concrete in severe marine conditions exposed upto a period of 150 days. This work investigates the influence of alccofine and fly ash as partial replacement of cement in various percentages (Alccofine - 5% replacement to cement content) and (fly ash - 0%, 15%, 30%, 50% & 60% to total cementitious content) on mechanical and durability properties (Permit ion permeability test and corrosion current density) of concrete. Usage of alccofine and high quantity of fly ash as additional cementitious materials in concrete has resulted in higher workability of concrete. Inclusion of alccofine shows an early strength gaining property whereas fly ash results in gaining strength at later stage. Concrete mixes containing 5% alccofine with 15% fly ash replacement reported greater compressive strength than the other concrete mixes cured in both curing conditions. Durability test conducted at 56 and 150 days indicated that concrete containing higher percentages of fly ash resulted in lower permeability as well lesser corrosion density.

scholarly journals Utilization of Crumb Rubber and High-Volume Fly Ash in Concrete for Environmental Sustainability: RSM-Based Modeling and Optimization

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3322
Author(s):  
Mugineysh Murali ◽  
Bashar S. Mohammed ◽  
Isyaka Abdulkadir ◽  
M. S. Liew ◽  
Wesam Salah Alaloul
Keyword(s):  
Fly Ash ◽  
Environmental Sustainability ◽  
High Volume ◽  
Crumb Rubber ◽  
Cementitious Materials ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
High Volume Fly Ash ◽  
Concrete Production ◽  
Rubber Concrete

Waste tire and fly ash (FA) are two waste materials whose disposal and rapid rate of accumulation are among the pressing sources of concern and threat to the environment. Although much research exists on the use of these materials in cementitious composites, very little literature is available on the effectiveness of combining them in high volumes for concrete production. This work aimed to utilize crumb rubber (CR) from waste tires as a partial replacement of fine aggregate at 15%, 22.25%, and 30% by volume, and high-volume fly ash (HVFA) replacement of cement at 50%, 60%, and 70% (by weight of cementitious materials) to produce high-volume fly ash–crumb rubber concrete (HVFA–CRC). Using the central composite design (CCD) option of the response surface methodology (RSM), 13 mixes were produced with different combinations and levels of the CR and FA (the input factors) on which the responses of interest (compressive, flexural, and tensile strengths) were experimentally investigated. Furthermore, the composite influence of CR and HVFA on the workability of the concrete was assessed using the slump test. The results showed a decline in the mechanical properties with increasing replacement levels of the CR and HVFA. However, up to 22.25% and 60% of CR and HVFA replacements, respectively, produced a structural HVFA–CRC with a compressive strength of more than 20 MPa at 28 days. Response predictive models were developed and validated using ANOVA at a 95% confidence level. The models had high R2 values ranging from 95.26 to 97.74%. Multi-objective optimization was performed and validated with less than 5% error between the predicted and experimental responses.

scholarly journals Effect of M Sand and Supplementary Cementitious Materials on Carbonation of Concrete

2019 ◽  
Vol 8 (4S2) ◽  
pp. 78-81
Keyword(s):  
Fly Ash ◽  
Steel Slag ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
River Sand ◽  
Conventional Concrete ◽  
Complete Replacement ◽  
Cement Ratio ◽  
Water To Cement Ratio

Carbonation is one of the imperative properties that affect the durability of concrete especially in case of reinforced structures. In this present study, an attempt has been taken to study the effect of M sand and other supplementary cementitious materials like silica fume, fly ash and steel slag as a partial replacement to cement. Different combinations with M sand, river sand and combinations of M sand and river sand with supplementary cementitious materials at water to cement ratio varying from 0.45 to 0.5 was studied. Results revealed that the complete replacement of river sand by M sand reduced the rate of carbonation but addition of supplementary cementitious along with either river sand or M sand resulted in increase over the rate of carbonation compared to conventional concrete.

scholarly journals Electrochemical Characteristics of High-Volume Fly Ash Lightweight Aggregate Concrete Incorporating Hydrated Lime

2020 ◽  
Vol 38 (11A) ◽  
pp. 1629-1639
Author(s):  
Tareq S. Al-Attar ◽  
Basil S. Alshathr ◽  
Mahmood E. Mohammed
Keyword(s):  
Fly Ash ◽  
Lightweight Concrete ◽  
High Volume ◽  
Hydrated Lime ◽  
Cementitious Materials ◽  
Chloride Ions ◽  
Partial Replacement ◽  
Lightweight Aggregate Concrete ◽  
Electrochemical Characteristics ◽  
High Volume Fly Ash

Currently, the use of  high-volume fly ash lightweight concrete, HVFALWC, has acquired popularity as a durable, resource-efficient, and an option of sustainability for varying concrete applications. Electrochemical characteristics such as half- cell potential, AC resistance, chloride penetration, free chloride, and pH value, up to 180 days were investigated for this type of concrete that uses 50% and 60% of fly ash as a replacement of Portland cement. The effect of using 10% hydrated lime powder as a partial substitute for the weight of cementitious materials for HVFALWC on electrochemical properties was also studied. The results in this study showed the possibility of producing friendly environmental structural lightweight concrete by using high volume fly ash (50% and 60%) as partial replacement by weight of cement. Furthermore, using 10% hydrated lime as partial replacement by weight of cementitious materials could be considered as a reliable measure to reduce the effect of chloride ions in the corrosion process.

scholarly journals Literature Review on Performance of Self Compacting Concrete Incorporating Copper Slag and Supplementary Cementitious Materials

2021 ◽  
Vol 9 (9) ◽  
pp. 1814-1819
Author(s):  
Aishwarya Dupaki
Keyword(s):  
Fly Ash ◽  
Copper Slag ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Self Compacting Concrete ◽  
Congested Area ◽  
Natural Aggregates ◽  
Day By Day

Abstract: This paper gives a review on self compacting concrete(SCC) to be made as partial replacing of cement by fly ash and metakaolin and partial replacing of fine aggregate with copper slag. Day by day production of concrete is increasing due to requirement of concrete is increasing with sufficient mechanical and durable properties in construction industry. Self compacting concrete is the special concrete which has ability of passing and filling of every corner of the congested area. So many researches are going on to increase mechanical and durable properties of SCC. Due to shortage of natural aggregates, researches are going on to use by-products or waste material as fine aggregate. Copper slag is a by-product produced during the process of production of copper. To achieve good mechanical and durable properties of self-compacting concrete cementitious material places an important role. Metakaolin and fly ash are used as the partial replacement of cement. In this paper an overview on the literature on mechanical behaviour of self-compacting concrete with partial replacement of cement by fly ash and metakaolin and partial replacement of fine aggregate with copper slag. Keywords: self compacting concrete, copper slag, fly ash, metakaolin, mechanical properties, durability

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 on blending of supplementary cementitious materials on performance of normal strength concrete

2019 ◽  
Vol 10 (3) ◽  
pp. 253-258
Author(s):  
S. Jagan
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Steel Slag ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Optimum Level ◽  
Fine Aggregate ◽  
River Sand ◽  
Split Tensile Strength

Sustainability and scarcity in resources are the two major issues to be dealt within the present scenario by effective utilization of alternative materials. In this present study, an attempt has been taken to study the effect of supplementary materials such as fly ash and silica fume as a partial replacement to cement and steel slag and M-sand as a replacement to river sand on strength and durability of concrete. In this study, concrete specimens were prepared based on five different mixes by varying the percentages of these supplementary materials. Various mechanical properties like compressive strength, split tensile strength and flexural strength were performed to ascertain the mix with optimum levels of replacement of supplementary materials for cement and fine aggregate. Durability property like water absorption test was performed on the mix with optimum values of strength. Results revealed that mix with higher percentages of steel slag, optimum level of silica fume and fly ash have shown higher strength and lesser permeability in concrete.

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