scholarly journals Effects of Partial Replacement of Coarse Aggregates with Reclaimed Rubber on the Mechanical Properties of Hardened Concrete

2020 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Kanmalai Williams ◽  
Eman Muhye Adeen Muhye Adeen Al-Hatali
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
Partial Replacement ◽  
Hardened Concrete ◽  
Coarse Aggregates ◽  
Concrete Members ◽  
Tension Tests ◽  
Base Study ◽  
Concrete Mix ◽  
Maximum Compressive Strength

<p>The replacement of conventional aggregates with alternate materials like Reclaimed Rubber (RR) results in reduction of self-weight and compressive strength of concrete. This reduction in self-weight further decreases the dead load which contributes towards contraction in size of concrete members and reinforcement requirements. This diminution in compressive strength is compensated by replacing cement with supplementary materials like Silica Fume, Fly Ash or GGBS. This research focuses on the effects of partial replacement of cement and coarse aggregates with Silica Fume (SF) and Reclaimed Rubber (RR) respectively in the concrete mix. Concrete mix was prepared for M20 grade by replacing cement and coarse aggregates with SF and RR respectively for cube and cylinder samples. A base study has been carried out through compression and split tension tests by partially replacing cement with SF in 3 percent increments up to 24 percent. Maximum compressive strength of 19.6N/mm<sup>2</sup>, 24.2N/mm<sup>2</sup> and 32.5N/mm<sup>2</sup> was obtained at 12% replacement of cement with SF by weight while testing specimens after 7, 14 and 28 days of curing. Maximum strength of 2.4N/mm<sup>2</sup>, 2.9N/mm<sup>2</sup> and 3.1N/mm<sup>2</sup> was obtained during split tension tests conducted after 7, 14 and 28 days of curing period. Further compression and tension tests were conducted replacing cement with 12%SF along with various proportions of RR replacing coarse aggregates after different curing periods. Experiments reveal that a combination of 12%SF and 9%RR replacement produces maximum compressive strength of 19.2N/mm<sup>2</sup>, 23.1N/mm<sup>2</sup> and 29.4N/mm<sup>2</sup> after curing the samples for 7, 14 and 28 days respectively. The tensile strength decreases as the rubber content is increased in the concrete mix along with optimum SF when compared with normal mix.</p>

Flexural behaviour of hybrid fibre (steel fiber and silica fume) reinforced self compacting composite concrete members

2014 ◽  
Vol 11 (4) ◽  
pp. 323-330 ◽  
Author(s):  
S. Arivalagan
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Hardened Concrete ◽  
Flexural Behaviour ◽  
Self Compacting Concrete ◽  
Engineering Structures ◽  
Conventional Concrete ◽  
Concrete Members

The present day world is witnessing the construction of very challenging and difficult civil engineering structures. Self-compacting concrete (SCC) offers several economic and technical benefits; the use of steel fiber extends its possibilities. Steel fiber acts as a bridge to retard their cracks propagation, and improve several characteristics and properties of the concrete. Therefore, an attempt has been made in this investigation to study the Flexural Behaviour of Steel Fiber Reinforced self compacting concrete incorporating silica fume in the structural elements. The self compacting concrete mixtures have a coarse aggregate replacement of 25% and 35% by weight of silica fume. Totally eight mixers are investigated in which cement content, water content, dosage of superplasticers were all constant. Slump flow time and diameter, J-Ring, V-funnel, and L-Box were performed to assess the fresh properties of the concrete. The variable in this study was percentage of volume fraction (1.0, 1.5) of steel fiber. Finally, five beams were to be casted for study, out of which one was made with conventional concrete, one with SCC (25% silica fume) and other were with SCC (25% silica fume + 1% of steel fiber, 25% silica fume + 1.5% of steel fiber) one with SCC (35% silica fume), and other were SCC (35% Silica fume + 1% of steel fiber, 35% Silica fume + 1.5% of steel fiber). Compressive strength, flexural strength of the concrete was determined for hardened concrete for 7 and 28 days. This investigation is also done to determine the increase the compressive strength by addition of silica fume by varying the percentage.

scholarly journals Consistency and mechanical properties of sustainable concrete blended with brick dust waste cementitious materials

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
S. Y. Amakye ◽  
S. J. Abbey ◽  
A. O. Olubanwo
Keyword(s):  
Tensile Strength ◽  
Fresh Concrete ◽  
Environmental Benefits ◽  
Partial Replacement ◽  
Target Range ◽  
Hardened Concrete ◽  
Index Test ◽  
Demolition Waste ◽  
Concrete Mix ◽  
Brick Dust

AbstractThe reuse of waste materials in civil engineering projects has become the topic for many researchers due to their economic and environmental benefits. In this study, brick dust waste (BDW) derived from cutting of masonry bricks and demolition waste which are normally dumped as land fill is used as partial replacement of cement in a concrete mix at 10%, 20% and 30% respectively, with the aim of achieving high strength in concrete using less cement due to the environmental problems associated with the cement production. To ascertain the effects of BDW on the consistency and mechanical performance of concrete mix, laboratory investigations on the workability of fresh concrete and the strength of hardened concrete were carried out. Slump and compaction index test were carried out on fresh concrete mix and unconfined compressive strength (UCS) test and tensile strength test were conducted on hardened concrete specimen after 7, 14 and 28 days of curing. The results showed high UCS and tensile strength with the addition of 10% BDW to the concrete mix, hence achieving the set target in accordance with the relevant British standards. A gradual reduction in strength was observed as BDW content increases, however, recording good workability as slump and compaction index results fell within the set target range in accordance with relevant British standards. Findings from this study concluded that BDW can partially replace cement in a concrete mix to up to 30% igniting the path to a cleaner production of novel concrete using BDW in construction work.

scholarly journals Pengaruh Penambahan Sat Additive Addition H.E Terhadap Kuat Tekan Beton

2020 ◽  
Vol 2 (1) ◽  
pp. 31-57
Author(s):  
Ni Ketut Sri Astati Sukawati
Keyword(s):  
Compressive Strength ◽  
Concrete Mixture ◽  
Partial Replacement ◽  
Work Related ◽  
Coarse Aggregates ◽  
Alternative Ingredients ◽  
Fine Aggregates ◽  
Compressive Strength Test ◽  
Compressive Strength Of Concrete ◽  
Artificial Stone

Concrete with various variants is a basic requirement in building a building. The concrete mixture is diverse depending on the planning made beforehand. The cement mixture is usually in the form of a mixture of artificial stone, cement, water and fine aggregates and coarse aggregates. Aggregates (fine aggregates and coarse aggregates) function as fillers in concrete mixtures. (Subakti, A., 1994). However, in building construction, additives are often added, but there is still a sense of uncertainty at the time of dismantling the mold and the reference before the concrete reaches sufficient strength to carry its own weight and the carrying loads acting on it. To overcome the time of carrying out work related to concrete, it is necessary to find an alternative solution, for example by looking for alternative ingredients of concrete mixture on the basis of consideration without reducing the quality of the concrete. From the results of previous studies it was stated that due to the partial replacement of cement with Fly Ash, the strength of the pressure and tensile strength of the concrete had increased (Budhi Saputro, A., 2008). Based on the description above, the author seeks to examine how the compressive strength of concrete characteristics that occur by adding additives Addition H.E in the concrete mixture and is there any additive Additon H.E effect on the increase in the compressive strength characteristic of the concrete. From the results of the study, it was found that the compressive strength of the concrete with the addition of additives HE was that after the compressive strength test of the concrete cube was carried out and the analysis of concrete compressive strength of 10 specimens, in each experiment a cube specimen was made with the addition of additons. HE with a dose of 80 cc, 120 cc, and 200 cc can accelerate and increase the compressive strength of concrete characteristics.

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 Utilization of Sugarcane Bagasse Ash from Power Co-generation Boilers as a Supplementary Cementitious Material

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Safiki Ainomugisha ◽  
Bisaso Edwin ◽  
Bazairwe Annet
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Sugarcane Bagasse ◽  
Low Income ◽  
Ordinary Portland Cement ◽  
Construction Material ◽  
Sustainable Construction ◽  
Partial Replacement ◽  
Hardened Concrete ◽  
Sugarcane Bagasse Ash

Concrete has been the world’s most consumed construction material, with over 10 billion tons of concrete annually. This is mainly due to its excellent mechanical and durability properties plus high mouldability. However, one of its major constituents; Ordinary Portland Cement is reported to be expensive and unaffordable by most low-income earners. Its production contributes about 5%–8% of global CO2 greenhouse emissions. This is most likely to increase exponentially with the demand of Ordinary Portland Cement estimated to rise by 200%, reaching 6000 million tons/year by 2050.  Therefore, different countries are aiming at finding alternative sustainable construction materials that are more affordable and offer greener options reducing reliance on non-renewable sources. Therefore, this study aimed at assessing the possibility of utilizing sugarcane bagasse ash from co-generation in sugar factories as supplementary material in concrete. Physical and chemical properties of this sugarcane bagasse ash were obtained plus physical and mechanical properties of fresh and hardened concrete made with partial replacement of Ordinary Portland Cement. Cost-benefit analysis of concrete was also assessed. The study was carried using 63 concrete cubes of size 150cm3 with water absorption studied as per BS 1881-122; slump test to BS 1881-102; and compressive strength and density of concrete according to BS 1881-116. The cement binder was replaced with sugarcane bagasse ash 0%, 5%, 10%, 15%, 20%, 25% and 30% by proportion of weight. Results showed the bulk density of sugarcane bagasse ash at 474.33kg/m3, the specific gravity of 1.81, and 65% of bagasse ash has a particle size of less than 0.28mm. Chemically, sugarcane bagasse ash contained SiO2, Fe2O3, and Al2O3 at 63.59%, 3.39%, and 5.66% respectively. A 10% replacement of cement gave optimum compressive strength of 26.17MPa. This 10% replacement demonstrated a cost saving of 5.65% compared with conventional concrete. 

scholarly journals Utilization Iron Filings and Microwave Heating in Roughening the Surface of Smoothed Coarse Aggregates

2018 ◽  
Vol 7 (4.20) ◽  
pp. 395
Author(s):  
Laith Mohammed Ridha Mahmmod Wajde ◽  
S. S. Alyhya Zainab ◽  
M. R. Abdul Rasoul ◽  
Abdulrasool T. Abdulrasool ◽  
. .
Keyword(s):  
Compressive Strength ◽  
Significant Influence ◽  
Smooth Surface ◽  
Coarse Aggregate ◽  
Microwave Treatment ◽  
Hardened Concrete ◽  
Equal Weight ◽  
Coarse Aggregates ◽  
Water Curing ◽  
Adhesion Process

Properties of coarse aggregate such as texture have a significant influence on the performance of fresh and hardened concrete. A smooth surface can enhance workability, yet a rougher one offers a stronger bond between aggregate and paste, resulting in higher strength. This research aims to roughen the texture of white smoothed aggregate by using cement-iron filings mortar with the aid of microwave maturation to accelerate the adhesion process of mortar-aggregate surface. The mortar was prepared by mixing an equal weight of cement and iron filings, of a particular size, with sand. Four different periods (2, 4, 6 and 8 mints.)  of microwave treatment in addition to water curing were considered plus one reference mortar which cured in only air for 24 hrs. The treated aggregate was then used for casting concrete specimens with a w/c ratio of 0.5 in which their properties being determined by means of density, compressive and tensile strengths observations. The main findings revealed that the concrete specimens contained microwave treated aggregate attained higher compressive strength compared with those treated in the air. Data also showed that concrete specimens with microwave treated aggregate possess better tensile properties as a consequence of the improvement in the transition zone.   

scholarly journals Concrete using sawdust as partial replacement of sand : Is it strong and does not endanger health?

2019 ◽  
Vol 258 ◽  
pp. 01015 ◽  
Author(s):  
Nurul Huda Suliman ◽  
Amir Atif Abdul Razak ◽  
Hazrina Mansor ◽  
Anizahyati Alisibramulisi ◽  
Norliyati Mohd Amin
Keyword(s):  
Compressive Strength ◽  
Construction Cost ◽  
Material Testing ◽  
Partial Replacement ◽  
Environmental Study ◽  
Hardened Concrete ◽  
Consumer Health ◽  
River Sand ◽  
Environmental Laboratory ◽  
Hazardous Use

This study was conducted to investigate the effectiveness of concrete using sawdust to partially replace the river sand which could reduce both environmental problems and construction cost. In this study, sawdust concrete has been produced where the river sand is replaced with sawdust by 5%, 10% and 15% of the total sand volume. Both wet concrete and hardened concrete (cubes specimens) were tested through material testing and cube testing to obtain the most optimum sawdust concrete design. In addition, specimens have also been tested in environmental laboratory to identify the extent of hazardous use of sawdust to consumer health. This is because the dust used is the waste taken from the unknown root of the level of cleanliness. The result shows that the most optimum design for producing sawdust concrete is that with 10% replacement of river sand. The result is based on the compressive strength obtained. The results of environmental study also show that this sawdust concrete is free from any harmful to health contaminants.

Assessment of mechanical and fire resistance for hybrid nano-clay and steel fibres concrete at different curing ages

2019 ◽  
Vol 11 (2) ◽  
pp. 189-203 ◽  
Author(s):  
Ola Bakr Shalby ◽  
Hala Mohamed Elkady ◽  
Elsayed Abdel Raouf Nasr ◽  
Mohamed Kohail
Keyword(s):  
Compressive Strength ◽  
Residual Strength ◽  
Low Cost ◽  
Partial Replacement ◽  
Fire Exposure ◽  
Content Type ◽  
Steel Fibres ◽  
Concrete Properties ◽  
Nano Clay ◽  
Concrete Mix

Purpose Nano-Clay (NC) is reported as a candidate partial replacement for cement, due to its abundance and relatively low cost - beside reported promotion of different concrete properties. On the other hand, Steel Fibres (SF) has proven to have a positive effect on post fire exposure residual strength of concrete. This paper aims to present the outcomes of a comprehensive research program assessing a hybrid mix between NC and SF in concrete mixtures (NCSF-CRETE). Design/methodology/approach Physical chemical and physical characterization of NC is performed using different tools as XRF spectrometer, and TEM micrograph. Fresh concrete properties of NSCF-CRETE as slump and air content are investigated. Enhancement in permeability using NSCF is verified by comparing its resistance to the penetration of chlorides resistance with regular concrete mix. Besides, the proposed NCSF-CRETE compressive strength is evaluated compared to mixes with NC and SF each used separately at different curing ages. Besides, NSCF and compared mixes are exposed to an indirect fire testing program – two hours exposure – for: 300, 450 and 600°C. Degradation in compressive strength was investigated after exposure to different temperatures and percentage of residual strength is reported. Findings Results indicated an improved performance of NCSF -CRETE of about 40% compared to regular concrete in compressive strength at normal conditions. This improvement extended to its behavior when subjected to indirect fire exposure NSCF also maintained 40% more strength than the residual in regular concrete mix – which suffered severe damage – after 2 h exposure to 600°C. Originality/value Using NCSF-Crete allows retrofitting the structure after exposure to such drastic conditions.

scholarly journals Development of Heavyweight Self-Compacting Concrete and Ambient-Cured Heavyweight Geopolymer Concrete Using Magnetite Aggregates

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1035 ◽  
Author(s):  
Afsaneh Valizadeh ◽  
Farhad Aslani ◽  
Zohaib Asif ◽  
Matt Roso
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Tensile Tests ◽  
Offshore Structures ◽  
Experimental Program ◽  
Geopolymer Concrete ◽  
Self Compacting Concrete ◽  
Coarse Aggregates ◽  
Maximum Compressive Strength ◽  
Heavyweight Concrete

Heavyweight self-compacting concrete (HWSCC) and heavyweight geopolymer concrete (HWGC) are new types of concrete that integrate the advantages of heavyweight concrete (HWC) with self-compacting concrete (SCC) and geopolymer concrete (GC), respectively. The replacement of natural coarse aggregates with magnetite aggregates in control SCC and control GC at volume ratios of 50%, 75%, and 100% was considered in this study to obtain heavyweight concrete classifications, according to British standards, which provide proper protection from sources that emit harmful radiations in medical and nuclear industries and may also be used in many offshore structures. The main aim of this study is to examine the fresh and mechanical properties of both types of mixes. The experimental program investigates the fresh properties of HWSCC and HWGC through the slump flow test. However, J-ring tests were only conducted for HWSCC mixes to ensure the flow requirements in order to achieve self-compacting properties. Moreover, the mechanical properties of both type of mixes were investigated after 7 and 28 days curing at an ambient temperature. The standard 100 × 200 mm cylinders were subjected to compressive and tensile tests. Furthermore, the flexural strength were examined by testing 450 × 100 × 100 mm prisms under four-point loading. The flexural load-displacement relationship for all mixes were also investigated. The results indicated that the maximum compressive strength of 53.54 MPa was achieved by using the control SCC mix after 28 days. However, in HWGC mixes, the maximum compressive strength of 31.31 MPa was achieved by 25% magnetite replacement samples. The overall result shows the strength of HWSCC decreases by increasing magnetite aggregate proportions, while, in HWGC mixes, the compressive strength increased with 50% magnetite replacement followed by a decrease in strength by 75% and 100% magnetite replacements. The maximum densities of 2901 and 2896 kg/m3 were obtained by 100% magnetite replacements in HWSCC and HWGC, respectively.

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