scholarly journals Field Application of Pervious Concerte for Recharge of Groundwater

2020 ◽  
Vol 9 (2) ◽  
pp. 341-350
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Permeability ◽  
Intersection Point ◽  
Absorption Capacity ◽  
Field Application ◽  
Pervious Concrete ◽  
Partial Replacement ◽  
Lateral Direction ◽  
Super Plasticizer

In the present study, an attempt has been made to investigate strength and permeability of pervious concrete made with different combinations of aggregate sizes (20mm,12.5mm and 10mm) and different mix proportions using flyash and super platiciciser). The main objective of this investigation is to apply the pervious concrete through a footpath to improve groundwater recharge by finding out the best combination of grading of aggregates and also the mix proportion with fly ash for obtaining optimal permeability and strength. The effect of partial replacement of cement with fly ash and super plasticizer on the compressive strength and the water permeability of pervious concrete are investigated. The analysis of the test results indicated that the proposed combination of materials have increased the compressive strength significantly and also, the water permeability. Even though, the individual performances (maximum strength and maximum permeability) of some of the combinations obtained are good, but it is expected in the study to have reasonable values for both to use pervious concrete in the field. Hence, in this study, it is considered the intersection point on the strength versus permeability graph as the best combination. So, the combination with 40% of 20mm, 30% of 12.5 mm and 10mm and 10%flyash with 90% opc (53 grade) without super plasticizer considered as the best which gives 24 MPa and 15.6 mm/s permeability.. A footpath of size 1.2 m (width) x 0.25 m (thickness) x 19 m (length) is selected for laying pervious concrete in the form of number of panels. A constant discharge is applied on to the footpath in lateral direction and it is found that the absorption capacity of the laid mix in the field is 115.52 litres/ m length.

scholarly journals Effect of Fly Ash and Fibres on Strength and Permeability Characteristics of Pervious Concrete

2019 ◽  
Vol 8 (4) ◽  
pp. 12089-12093
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Water Permeability ◽  
High Strength ◽  
High Water ◽  
Pervious Concrete ◽  
Storm Water ◽  
Water Runoff ◽  
Concrete Mix

Conventional normal cement concrete is generally used as construction material of buildings. The impervious nature of concrete contributes to the increased water runoff into drainage system, over-burdening the infrastructure and causing excessive flooding in built-up areas. Pervious concrete has become significantly popular during recent decades, because of its potential contribution in solving environmental issues. Pervious concrete is a type of concrete with significantly high water permeability compared to conventional concrete. It has been mainly developed for draining water from surface to underground, so that storm water runoff is reduced. Due to high water permeability then normal concrete, pervious concrete has very low compressive strength. The characteristic of high permeability of pervious concrete contributes to its advantage in storm water management. However, the mechanical property such as low compressive strength limits the application of pervious concrete to the roads having light volume traffic. It is observed form previous studies that the strength of pervious concrete can be enhanced by substituting some of the cement with other materials, such as fly ash and fibres. The objective of present study was to make pervious concrete mix with high strength and pore properties by partial replacement of cement with fly ash and using steel and glass fibres. For this purpose cubes beams were casted with and without replacement of cement with flyash and addition of steel and glass fiber by total weight of concrete mix. Test such as compressive strength, flexural strength, total porosity and Infiltration rate were performed. It was observed addition of fly ash decreased the compressive as well as flexural strength of the pervious concrete. Further, incorporation of 1% steel fibres by weight of concrete mix was found adequate in achieving high strength and permeability, when compared to control mix concrete

scholarly journals A Study on Suitability of Foamed Sandcrete Solid Block with Fly-Ash as Partial Replacement of Sand

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Monsuru O Popoola ◽  
Olanrewaju A Apampa ◽  
Olasunkanmi Adekitan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Absorption Capacity ◽  
Partial Replacement ◽  
Dry Density ◽  
Water Absorption Capacity ◽  
Wall Unit ◽  
Solid Block ◽  
Curing Age

In this study, the properties of foamed sandcrete solid block (FSSB) with varying percentage of sand replacement with fly-ash were investigated. These properties include workability, wet and dry density, stability, water absorption capacity and compressive strength. 150mm cube specimens were used for the determination of both the compressive strength and the dry density of the FSSB. The plastic density was investigated using a container of known volume, and its workability determined using the slump test. The fly-ash content was varied from 0 to 50% at interval of 10%. The specimens without the fly-ash served as the control. At the designed density of 1500kg/m3, the results for the control specimens at 28 day curing age was 3.74N/mm2. As for 50% sand replacement with fly-ash, the compressive strength were 2.37 N/mm, and 3.31 N/mm2 at 7-days 28-days curing age respectively, both satisfied the minimum compressive strength of 1.8N/mm2 and 2.5N/mm2 at the curing age of 7-days and 28-days respectively for conventional sandcrete block for building wall unit as allowed by Nigerian Industrial Standard (N.I.S). The result also shows an appreciable decrease in density of FSSB with 1411.8kg/m3, as compared to dense sandcrete solid block with average of 1950kg/m3, which will significantly reduce the overall dead load of the building structure. FSSB with 50% sand replacement with fly-ash also showed a much improved water absorption capacity of 9.81% as control specimen of 11.73%. Fly-ash can be used to reduce the quantity of sand used in FSSB production; thus ridding our environment of potentially harmful wastes, as well as reduce the consumption of non-renewable resources. Keywords— Foamed Sandcrete, Compressive Strength, fly-ash, dry density, stability, cement

scholarly journals Strength Time–Varying and Freeze–Thaw Durability of Sustainable Pervious Concrete Pavement Material Containing Waste Fly Ash

2018 ◽  
Vol 11 (1) ◽  
pp. 176 ◽  
Author(s):  
Hanbing Liu ◽  
Guobao Luo ◽  
Longhui Wang ◽  
Yafeng Gong
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Pervious Concrete ◽  
Early Age ◽  
Pavement Materials ◽  
Freeze Thaw ◽  
Replacement Method ◽  
Porosity And Permeability ◽  
Volume Method

Pervious concretes, as sustainable pavement materials, have great advantages in addressing a number of environmental issues. Fly ash, as the industrial by-product waste, is the most commonly used as cement substitute in concrete. The objective of this paper is to study the effects of waste fly ash on properties of pervious concrete. Fly ash was used to replace cement with equivalent volume method at different levels (3%, 6%, 9%, and 12%). The control pervious concrete and fly ash modified pervious concrete were prepared in the laboratory. The porosity, permeability, compressive strength, flexural strength, and freeze–thaw resistance of all mixtures were tested. The results indicated that the addition of fly ash decreased the early-age (28 d) compressive strength and flexural strength, but the long-term (150 d) compressive strength and flexural strength of fly ash modified pervious concrete were higher than that of the early-age. The adverse effect of fly ash on freeze–thaw resistance of pervious concrete was observed when the fly ash was added. The porosity and permeability of all pervious concrete mixtures changed little with the content of fly ash due to the use of equal volume replacement method. Although fly ash is not positive to the properties of pervious concrete, it is still feasible to apply fly ash as a substitute for cement in pervious concrete.

scholarly journals Effect of Fly Ash on the Compressive Strength of Green Concrete

2020 ◽  
Vol 10 (3) ◽  
pp. 5728-5731 ◽  
Author(s):  
S. A. Chandio ◽  
B. A. Memon ◽  
M. Oad ◽  
F. A. Chandio ◽  
M. U. Memon
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Recycled Aggregates ◽  
Waste Materials ◽  
Partial Replacement ◽  
Equal Proportion ◽  
Standard Size ◽  
Green Concrete ◽  
Coarse Aggregates ◽  
Management Issues

This research paper aims at investigating the effects of fly ash as cement replacement in green concrete made with partial replacement of conventional coarse aggregates with coarse aggregates from demolishing waste. Green concrete developed with waste materials is an active area of research as it helps in reducing the waste management issues and protecting the environment. Six concrete mixes were prepared using 1:2:4 ratio and demolishing waste was used in equal proportion with conventional aggregates, whereas fly ash was used from 0%-10% with an increment of 2.5%. The water-cement ratio used was equal to 0.5. Out of these mixes, one mix was prepared with all conventional aggregates and was used as the control, and one mix with 0% fly ash had only conventional and recycled aggregates. The slump test of all mixes was determined. A total of 18 cylinders of standard size were prepared and cured for 28 days. After curing the compressive strength of the specimens was evaluated under gradually increasing load until failure. It is observed that 5% replacement of cement with fly ash and 50% recycled aggregates gives better results. With this level of dosage of two waste materials, the reduction in compressive strength is about 11%.

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.

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.

Macroscopic and Microscopic Properties of High Performance Concrete with Partial Replacement of Cement by Fly Ash

2019 ◽  
Vol 292 ◽  
pp. 108-113 ◽  
Author(s):  
Josef Fládr ◽  
Petr Bílý ◽  
Roman Chylík ◽  
Zdeněk Prošek
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Partial Replacement ◽  
Experimental Program ◽  
Second Phase ◽  
Depth Of Penetration ◽  
Cement Replacement

The paper describes an experimental program focused on the research of high performance concrete with partial replacement of cement by fly ash. Four mixtures were investigated: reference mixture and mixtures with 10 %, 20 % and 30 % cement weight replaced by fly ash. In the first stage, the effect of cement replacement was observed. The second phase aimed at the influence of homogenization process for the selected 30% replacement on concrete properties. The analysis of macroscopic properties followed compressive strength, elastic modulus and depth of penetration of water under pressure. Microscopic analysis concentrated on the study of elastic modulus, porosity and mineralogical composition of cement matrix using scanning electron microscopy, spectral analysis and nanoindentation. The macroscopic results showed that the replacement of cement by fly ash notably improved compressive strength of concrete and significantly decreased the depth of penetration of water under pressure, while the improvement rate increased with increasing cement replacement (strength improved by 18 %, depth of penetration by 95 % at 30% replacement). Static elastic modulus was practically unaffected. Microscopic investigation showed impact of fly ash on both structure and phase mechanical performance of the material.

scholarly journals Modification of Ordinary Concrete Using Fly Ash from Combustion of Municipal Sewage Sludge

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 487 ◽  
Author(s):  
Gabriela Rutkowska ◽  
Piotr Wichowski ◽  
Małgorzata Franus ◽  
Michał Mendryk ◽  
Joanna Fronczyk
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sewage Sludge ◽  
Penetration Depth ◽  
Environmental Benefits ◽  
Municipal Sewage ◽  
Partial Replacement ◽  
Municipal Sewage Sludge ◽  
Water Penetration ◽  
The Impact

This article focuses on the impact of fly ash from the combustion of municipal sewage sludge (FAMSS) as a cement additive in the amounts of 5%, 10%, 15%, 20% and 25% (by mass) on selected concrete properties. In the course of the experimental work, water penetration depth and compressive strength measurements were made at various periods of curing (from 2 to 365 days). In addition, the potential impact of FAMSS on the natural environment was examined by determining the leachability of heavy metals. FAMSS-modified concretes showed small values of water penetration depth (lower than 50 mm), as well as good compressive strength (reaching minimum class C30/37 after 130 days of maturing)—similar to the compressive strength obtained for conventional concrete. In addition, the partial replacement of cement with FAMSS has environmental benefits, expressed as a reduction in CO2 emissions. In addition, study has shown that compliance with environmental requirements is associated with heavy metal leaching.

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.

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