Drying Shrinkage of Fly Ash Mortar Mixed with Seawater

2015 ◽  
Vol 802 ◽  
pp. 118-123 ◽  
Author(s):  
John Wilmer Bautista ◽  
John Benedict Crockett ◽  
Beatrice Ann Liu ◽  
Timothy John Obra ◽  
Cheryl Lyne Roxas
Keyword(s):  
Carbon Dioxide ◽  
Compressive Strength ◽  
Fly Ash ◽  
Carbon Dioxide Emissions ◽  
Drying Shrinkage ◽  
Water Shortage ◽  
Ash Content ◽  
Partial Substitution ◽  
Partial Replacement ◽  
Micro Cracks

Drying shrinkage in mortar produces cracks and micro-cracks which affect the durability of a structure. The effects of seawater as a substitute to freshwater and fly ash as a partial replacement for cement were investigated in this study in order to address the predicted water shortage by 2025 and the increasing carbon footprint from carbon dioxide emissions worldwide. Moreover, these materials are also more economical alternatives to freshwater and cement. Rectangular prism specimens with varying fly ash content (10%, 15%, 20%, 25%, and 30%) were cast to measure the drying shrinkage in mortar while 50-mm cube mortar specimens were prepared to determine the compressive strength. This study investigated whether the addition of fly ash and seawater reduced the drying shrinkage of mortar. From the results, it was found that mortar specimens with 20% fly ash replacement achieved the highest early and late strengths. Partial substitution of fly ash would result to shrinkage in mortar while substitution of seawater to freshwater counteracts the effects of fly ash, thus producing less shrinkage. Fly ash content between 20%-25% combined with seawater produces the least shrinkage value without compromising the minimum required compressive strength.

High Volume Slag and Slag-Fly Ash Blended Cement Pastes Containing Nano Silica

2019 ◽  
Vol 967 ◽  
pp. 205-213
Author(s):  
Faiz U.A. Shaikh ◽  
Anwar Hosan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Cement Paste ◽  
Ordinary Portland Cement ◽  
Blended Cement ◽  
High Volume ◽  
Ash Content ◽  
Partial Replacement ◽  
Nano Silica ◽  
Cement Pastes

This paper presents the effect of nanosilica (NS) on compressive strength and microstructure of cement paste containing high volume slag and high volume slag-fly ash blend as partial replacement of ordinary Portland cement (OPC). Results show that high volume slag (HVS) cement paste containing 60% slag exhibited about 4% higher compressive strength than control cement paste, while the HVS cement paste containing 70% slag maintained the similar compressive strength to control cement paste. However, about 9% and 37% reduction in compressive strength in HVS cement pastes is observed due to use of 80% and 90% slag, respectively. The high volume slag-fly ash (HVSFA) cement pastes containing total slag and fly ash content of 60% exhibited about 5%-16% higher compressive strength than control cement paste. However, significant reduction in compressive strength is observed in higher slag-fly ash blends with increasing in fly ash contents. Results also show that the addition of 1-4% NS improves the compressive strength of HVS cement paste containing 70% slag by about 9-24%. However, at higher slag contents of 80% and 90% this improvement is even higher e.g. 11-29% and 17-41%, respectively. The NS addition also improves the compressive strength by about 1-59% and 5-21% in high volume slag-fly ash cement pastes containing 21% fly ash+49%slag and 24% fly ash+56%slag, respectively. The thermogravimetric analysis (TGA) results confirm the reduction of calcium hydroxide (CH) in HVS/HVSFA pastes containing NS indicating the formation of additional calcium silicate hydrate (CSH) gels in the system. By combining slag, fly ash and NS in high volumes e.g. 70-80%, the carbon footprint of cement paste is reduced by 66-76% while maintains the similar compressive strength of control cement paste. Keywords: high volume slag, nanosilica, compressive strength, TGA, high volume slag-fly ash blend, CO2 emission.

scholarly journals Experiments on Foamed Concrete for the Development of Building Blocks

2020 ◽  
Vol 8 (5) ◽  
pp. 2824-2829
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Building Blocks ◽  
Ash Content ◽  
Partial Replacement ◽  
Dry Density ◽  
Load Bearing ◽  
Concrete Building ◽  
Concrete Blocks ◽  
Foamed Concrete

Foamed concrete is an innovative and versatile lightweight building material, which is a cement-based mortar consisting of at least 20% of its volume filled with air. Use of lightweight foamed concrete blocks with densities less than 1800 kg/m3 as infills will lead to the design of slender sections. Further, the thermal insulation properties of foamed concrete blocks made it more popular in construction industry. This paper discusses the development of foamed concrete building blocks for load bearing and non-load bearing structures. To make the mix more sustainable, the feasibility of fly ash as a partial replacement to cement is also explored. The variables considered for the production of foamed concrete are foam volume, water/powder (mix of cement and fly ash) ratio, fly ash content and sand/powder ratio. Analytical model is also developed for compressive strength and dry density of foamed concrete considering different variables and it is validated. Compressive strength is found to be increasing with the increase in dry density and with increase in fly ash content. Thermal conductivity is observed to be reduced by the addition of fly ash content

scholarly journals Concrete manufactured with crushed asphalt as partial replacement of natural aggregates

2016 ◽  
Vol 66 (324) ◽  
pp. 101 ◽  
Author(s):  
L. Coppola ◽  
P. Kara ◽  
S. Lorenzi
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Drying Shrinkage ◽  
Experimental Results ◽  
Recycled Aggregate ◽  
Partial Substitution ◽  
Partial Replacement ◽  
Negative Effect ◽  
Natural Aggregates ◽  
Positive Effect

The paper focuses on the reuse of crushed asphalt (GA) as a partial replacement (up to 20%) of natural aggregates for concrete manufacture. Addition of GA aggregates produced a positive effect on workability loss. The GA mixes, however, showed a significant tendency to bleed and segregate at the highest replacement percentage applied. GA led to a decrease of compressive strength in concrete (with respect to that of the reference concrete) up to 50% due to the weakness of the cement paste / recycled aggregate interface. To compensate for this negative effect, a reduction of w/c for the GA concretes was necessary. A decrease of w/c allowed the GA concretes to show drying shrinkage values substantially similar to those of reference concrete with the same cement factor. The experimental results confirmed the possibility of partial substitution (max. 15%) of natural aggregates with crushed asphalt for making concrete.

Study on Performance of High-Performance Concrete Made with Fly Ash and Polypropylene Fiber

2011 ◽  
Vol 99-100 ◽  
pp. 1027-1030
Author(s):  
Lan Fang Zhang ◽  
Rui Yan Wang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Significant Influence ◽  
High Performance ◽  
High Performance Concrete ◽  
Impact Resistance ◽  
Polypropylene Fiber ◽  
Drying Shrinkage ◽  
Ash Content ◽  
Fiber Content

High-performance concrete was made with fly ash and polypropylene fiber, the study shows that when fly ash content was 20% and polypropylene fiber was 0.6~1.2kg/m3, it had no significant influence on the workability of concrete, however the changes of 28d compressive strength and drying shrinkage of concrete are within 10%, but it can reduce brittle and improve toughness, and impact resistance of concrete is improved obviously, when polypropylene fiber content was 0.9kg/m3, it can improve over three times.

scholarly journals Compressive Strength of Mortar with Partial Replacement of Cement by Fly Ash and GGBFS.

2021 ◽  
Vol 14 (4) ◽  
pp. 146-155
Author(s):  
Safie Safie Mahdi Oleiwi
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Construction Industry ◽  
Optimal Level ◽  
Partial Substitution ◽  
Partial Replacement ◽  
Curing Time ◽  
Granulated Blast Furnace Slag ◽  
Strength Tests ◽  
Furnace Slag

The compressive strength characteristics of mortar containing Ground Granulated Blast Furnace Slag (GGBFS) and Fly Ash (FA) in mortar by partial substitution of cement are investigated in this work. The increased demand for cement in the construction industry is a concern for environmental degradation; in this case, waste materials such as GGBFS and FA are used to replace cement. The optimal level of GGBFS and FA was determined using a percentage range of 0% to 40% for different curing days. Compressive strength tests were performed on the replaced mortar. For all mixes, the binder-to-water ratio was kept at 0.4. The compressive strength tests were conducted for 7, 28 and 90 days of curing on a Mortar. The result obtained that as the curing time increased the compressive strength of mortar containing GGBFS and FA increased. In comparison to M1 (cement only), the compressive strength improved by 13.15 percent and 15.5 percent at M3 (20%FA) and M8 (30%GGBFS), respectively. The results showed that adding GGBFS and FA to mortar improve compressive strength, which is improves the mechanical properties of the mortar.

scholarly journals Analysis of Concrete Block by Partial Replacement of Cement with Fly Ash

2021 ◽  
Vol 1 (1) ◽  
pp. 15-19
Author(s):  
Vidya Sagar Khanduri ◽  
Shivek Sharma
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Setting Time ◽  
Control Level ◽  
Concrete Block ◽  
Target Strength ◽  
Partial Substitution ◽  
Partial Replacement ◽  
Sieve Analysis ◽  
Initial Strength

The objective of this research is to enhance the properties of concrete by using Fly Ash as a partial substitution of concrete. Tests carried out on cement are Initial and Final setting time and on aggregates, specific gravity and sieve analysis. The mean target strength with given compressive strength at 28 day and quality control level is calculated. Concrete blend proportions for the first tryout mix is calculated and casting of cube of 15mm size with curing for 28 days, and then test for strength using UTM/CTM machines. C-S-H gel as well as Calcium hydroxide as bi product when reacts with water. C-S-H gel has an ability to keep the ingredients together by making a proper bond whereas lime which is freely available can react with atmospheric moisture and cause efflorescence. In such cases if we use fly ash, it reacts with free lime and produces C-SH gel again and water as bi product. We have used Fly ash as a partial replacement of cement with variation of fly ash in percentage. In this study fly ash add in increment of 5%, 10%, 15%, 20%, 25%, 30% and 35% replacement of cement which has shown satisfactory results in the strength of the concrete. Fly Ash improved the workability of the concrete, decreases the bleeding, surface finish and increases the cohesiveness. Compressive strength is comparatively increased. The initial strength of concrete with fly ash has lower strength but acquires higher strength after 56 days; which shows that more the nos. of curing days more will be the strength. Thus, it can be used in areas of construction such as dams, pavements etc.

scholarly journals Analysis of Concrete Block by Partial Replacement of Cement with Fly Ash

2021 ◽  
pp. 15-19
Author(s):  
Vidya Sagar Khanduri ◽  
◽  
Shivek Sharma ◽  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Setting Time ◽  
Control Level ◽  
Concrete Block ◽  
Target Strength ◽  
Partial Substitution ◽  
Partial Replacement ◽  
Sieve Analysis ◽  
Initial Strength

The objective of this research is to enhance the properties of concrete by using Fly Ash as a partial substitution of concrete. Tests carried out on cement are Initial and Final setting time and on aggregates, specific gravity and sieve analysis. The mean target strength with given compressive strength at 28 day and quality control level is calculated. Concrete blend proportions for the first tryout mix is calculated and casting of cube of 15mm size with curing for 28 days, and then test for strength using UTM/CTM machines. C-S-H gel as well as Calcium hydroxide as bi product when reacts with water. C-S-H gel has an ability to keep the ingredients together by making a proper bond whereas lime which is freely available can react with atmospheric moisture and cause efflorescence. In such cases if we use fly ash, it reacts with free lime and produces C-SH gel again and water as bi product. We have used Fly ash as a partial replacement of cement with variation of fly ash in percentage. In this study fly ash add in increment of 5%, 10%, 15%, 20%, 25%, 30% and 35% replacement of cement which has shown satisfactory results in the strength of the concrete. Fly Ash improved the workability of the concrete, decreases the bleeding, surface finish and increases the cohesiveness. Compressive strength is comparatively increased. The initial strength of concrete with fly ash has lower strength but acquires higher strength after 56 days; which shows that more the nos. of curing days more will be the strength. Thus, it can be used in areas of construction such as dams, pavements etc.

scholarly journals Effect of Fly Ash on Compressive Strength, Drying Shrinkage, and Carbonation Depth of Mortar with Ferronickel-Slag Powder

2021 ◽  
Vol 11 (3) ◽  
pp. 1037
Author(s):  
Se-Jin Choi ◽  
Ji-Hwan Kim ◽  
Sung-Ho Bae ◽  
Tae-Gue Oh
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Construction Industry ◽  
Bituminous Coal ◽  
Raw Materials ◽  
Drying Shrinkage ◽  
The Other ◽  
Test Results ◽  
Slag Powder ◽  
Ferronickel Slag

In recent years, efforts to reduce greenhouse gas emissions have continued worldwide. In the construction industry, a large amount of CO2 is generated during the production of Portland cement, and various studies are being conducted to reduce the amount of cement and enable the use of cement substitutes. Ferronickel slag is a by-product generated by melting materials such as nickel ore and bituminous coal, which are used as raw materials to produce ferronickel at high temperatures. In this study, we investigated the fluidity, microhydration heat, compressive strength, drying shrinkage, and carbonation characteristics of a ternary cement mortar including ferronickel-slag powder and fly ash. According to the test results, the microhydration heat of the FA20FN00 sample was slightly higher than that of the FA00FN20 sample. The 28-day compressive strength of the FA20FN00 mix was approximately 39.6 MPa, which was higher than that of the other samples, whereas the compressive strength of the FA05FN15 mix including 15% of ferronickel-slag powder was approximately 11.6% lower than that of the FA20FN00 mix. The drying shrinkage of the FA20FN00 sample without ferronickel-slag powder was the highest after 56 days, whereas the FA00FN20 sample without fly ash showed the lowest shrinkage compared to the other mixes.

Physical Properties of Cement Mortar Containing Waste Ash

2015 ◽  
Vol 804 ◽  
pp. 129-132
Author(s):  
Sumrerng Rukzon ◽  
Prinya Chindaprasirt
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Cement Mortar ◽  
Ash Content ◽  
Water Requirement ◽  
Test Results ◽  
Pozzolanic Material ◽  
Materials Used

This research studies the potential for using waste ash from industrial and agricultural by-products as a pozzolanic material. Classified fly ash (FA) and ground rice husk ash (RA) were the materials used. Water requirement, compressive strength and porosity of cement mortar were investigated. Test results indicated that FA and RA (waste ash) have a high potential to be used as a good pozzolanic material. The water requirement of mortar mix decreases with the increases in fly ash content. For ground rice husk ash (RA), the water requirement of mortar mix increases with the increases in rice husk ash content. In addition, the reduction in porosity was associated with the increase in compressive strength.

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