scholarly journals Feasibility of Developing Sustainable Concrete Using Environmentally Friendly Coarse Aggregate

2020 ◽  
Vol 10 (15) ◽  
pp. 5207
Author(s):  
Chamila Gunasekara ◽  
Charitha Seneviratne ◽  
David W. Law ◽  
Sujeeva Setunge
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Mechanical Performance ◽  
Drying Shrinkage ◽  
Strength Development ◽  
Design Strength ◽  
Coarse Aggregates ◽  
Increasing Demand ◽  
Quality Material

Quarry aggregate reserves are depleting rapidly within Australia and the rest of the world due to an increasing demand for aggregates driven by expansion in construction. The annual production of premix concrete in Australia is approximately 30 million cubic meters, while 3–5% of concrete delivered to site remains unused and is disposed of in landfill or crushing plants. The production of coarse aggregates using this waste concrete is potentially a sustainable approach to reduce environmental and economic impact. A testing program has been conducted to investigate mechanical performance and permeation characteristics of concrete produced using a novel manufactured coarse aggregate recycled directly from fresh premix concrete. The recycled coarse aggregate (RCA) concrete satisfied the specified 28-day design strength of 25 MPa and 40 MPa at 28 days and a mean compressive strength of 60 MPa at 90 days. Aggregate grading was observed to determine strength development, while low water absorption, low drying shrinkage, and higher packing density indicate that the RCA concrete is a high-quality material with a dense pore structure. The rough fracture surface of the aggregate increased the bond between C-S-H gel matrix and RCA at the interfacial transition zone. Furthermore, a good correlation was observed between compressive strength and all other mechanical properties displayed by the quarried aggregate concrete. The application of design equations as stated in Australian standards were observed to provide a conservative design for RCA concrete structures based on the mechanical properties.

scholarly journals Influence of Glass Fibers on Mechanical Properties of Concrete with Recycled Coarse Aggregates

2019 ◽  
Vol 5 (5) ◽  
pp. 1007-1019 ◽  
Author(s):  
Babar Ali ◽  
Liaqat Ali Qureshi ◽  
Ali Raza ◽  
Muhammad Asad Nawaz ◽  
Safi Ur Rehman ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Glass Fibers ◽  
Construction Material ◽  
Concrete Compressive Strength ◽  
Coarse Aggregates ◽  
Highly Sensitive

Despite plain cement concrete presenting inferior performance in tension and adverse environmental impacts, it is the most widely used construction material in the world. Consumption of fibers and recycled coarse aggregates (RCA) can add ductility and sustainability to concrete. In this research, two mix series (100%NCA, and 100%RCA) were prepared using four different dosages of GF (0%GF, 0.25%GF, 0.5%GF, and 0.75%GF by volume fraction).  Mechanical properties namely compressive strength, splitting tensile strength, and flexural strength of each concrete mixture was evaluated at the age of 28 days. The results of testing indicated that the addition of GF was very useful in enhancing the split tensile and flexural strength of both RCA and NCA concrete. Compressive strength was not highly sensitive to the addition of GF. The loss in strength that occurred due to the incorporation of RCA was reduced to a large extent upon the inclusion of GF. GF caused significant improvements in the split tensile and flexural strength of RCA concrete. Optimum dosage of GF was determined to be 0.25% for NCA, and 0.5% for RCA concrete respectively, based on the results of combined mechanical performance (MP).

scholarly journals PENGARUH CANGKANG KEMIRI SEBAGAI PENGGANTI AGREGAT KASAR TERHADAP SIFAT MEKANIK BETON (EFFECT OF CANDLENUT SHELL AS SUBTITUTE COARSE AGGREGATE TO THE MECHANICAL PROPERTIES OF CONCRETE)

2018 ◽  
Author(s):  
Erniati Bachtiar
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Concrete Mixture ◽  
Construction Technology ◽  
Concrete Compressive Strength ◽  
Coarse Aggregates ◽  
Volume Weight ◽  
Compressive Strength Test

Concrete construction technology is directed to be sustainable and ecofriendly. The waste of the candlenut shell as a substitute for the coarse aggregate of concrete mixture is known that the candlenut shell has a hard texture so it may be used as a substitute for coarse aggregates in concrete. The purpose of the research was to determine the effect of Candlenut shell as a substitute of coarse aggregate on physical properties (slump test, bleeding, segregation, volume weight) and mechanical properties (compressive strength and tensile strength) of concrete using Candlenut shell as replacement material of the coarse aggregate. The variation of the research was percentage of the Candlenut shell in the concrete mixture, that was 0%, 25%, 50%, 75% and 100% to the coarse aggregate volume in the concrete mixture. Number of specimens in reseach was each 5 pieces each variation. Testing of mechanical properties of concrete (compressive strength and tensile strength) was performed at 28 days. Testing of the concrete for compressive strength test and tensile strength on age 28 days. Concrete using candlenut shell as a substitute of coarse aggregates has decreased compressive strength respectively 11.72 MPa (37.71%) for 25% candlenut shell; 15.54 MPa (50.00%) for 50% candlenut shell; 18.35 MPa (59.02%) for 75% candlenut shell; And 18,85 MPa (60,66%) for 100% candlenut shell from of the 0% candlenut shell with compressive strength of 31.08 Mpa. Concrete using for 25% candlenut shell as a substitute for coarse aggregates decreased tensile strength respectively of 0.95 MPa (28.70%) for 25% candlenut shell; 1.21 MPa (36.56%) for 50% candlenut shell; 1.27 MPa (38.37%) for 75% candlenut shell; And 1.40 MPa (42.30%) for 100% candlenut shell from of the 0% candlenut shell with the tensile strength of BN of 3.31 MPa. The decrease in the value of compressive strength and tensile strength is strongly influenced by the increasing percentage of Candlenut shells on concrete

scholarly journals Effects of the Variety and Content of Natural Pozzolan Coarse Aggregate on the Thermo-Mechanical Properties of Concrete

2021 ◽  
Vol 12 (4) ◽  
pp. 5405-5415
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
The Other ◽  
Natural Pozzolan ◽  
Coarse Aggregates ◽  
Natural Aggregate ◽  
Middle Atlas

The present study investigated the effects of the variety and content of three natural pozzolan coarse aggregates on concrete. Natural pozzolan aggregates have been obtained from three volcanoes (Boutagrouine, Timahdite, and Jbel Hebri) located in the Middle Atlas region in Morocco. The three pozzolans studied were characterized, and then a comparison was made by replacing the natural aggregate with the pozzolan aggregate in the concrete in different percentages, namely 25, 50, and 100 % in volume. The results showed that the variety and content of pozzolan aggregate have a significant impact on the properties of concrete, primarily caused by the characterization of pozzolan aggregate. The density of concrete decreases with the addition of pozzolan aggregate, which decreases depending on the type of pozzolan aggregate used. The highest compressive strength was measured in the concrete specimens prepared with aggregate BP while the lowest compressive strength was noted in the concrete specimens prepared with aggregate RP. On the other hand, the substitution of NA at 100% by BP, GP, and RP aggregates leads to a decrease in the thermal conductivity of about 67%, 62%, and 55% respectively.

scholarly journals EFFECT OF CANDLENUT SHELL AS SUBTITUTE COARSE AGGREGATE TO THE MECHANICAL PROPERTIES OF CONCRETE

2018 ◽  
Author(s):  
Erniati Bachtiar
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Concrete Mixture ◽  
Construction Technology ◽  
Concrete Compressive Strength ◽  
Coarse Aggregates ◽  
Volume Weight ◽  
Compressive Strength Test

Concrete construction technology is directed to be sustainable and ecofriendly. The waste of the candlenut shell as a substitute for the coarse aggregate of concrete mixture is known that the candlenut shell has a hard texture so it may be used as a substitute for coarse aggregates in concrete. The purpose of the research was to determine the effect of Candlenut shell as a substitute of coarse aggregate on physical properties (slump test, bleeding, segregation, volume weight) and mechanical properties (compressive strength and tensile strength) of concrete using Candlenut shell as replacement material of the coarse aggregate. The variation of the research was percentage of the Candlenut shell in the concrete mixture, that was 0%, 25%, 50%, 75% and 100% to the coarse aggregate volume in the concrete mixture. Number of specimens in reseach was each 5 pieces each variation. Testing of mechanical properties of concrete (compressive strength and tensile strength) was performed at 28 days. Testing of the concrete for compressive strength test and tensile strength on age 28 days. Concrete using candlenut shell as a substitute of coarse aggregates has decreased compressive strength respectively 11.72 MPa (37.71%) for 25% candlenut shell; 15.54 MPa (50.00%) for 50% candlenut shell; 18.35 MPa (59.02%) for 75% candlenut shell; And 18,85 MPa (60,66%) for 100% candlenut shell from of the 0% candlenut shell with compressive strength of 31.08 Mpa. Concrete using for 25% candlenut shell as a substitute for coarse aggregates decreased tensile strength respectively of 0.95 MPa (28.70%) for 25% candlenut shell; 1.21 MPa (36.56%) for 50% candlenut shell; 1.27 MPa (38.37%) for 75% candlenut shell; And 1.40 MPa (42.30%) for 100% candlenut shell from of the 0% candlenut shell with the tensile strength of BN of 3.31 MPa. The decrease in the value of compressive strength and tensile strength is strongly influenced by the increasing percentage of Candlenut shells on concrete.

scholarly journals Evaluation of Workability and Mechanical Properties of Bottom Ash Aggregate Concrete

2020 ◽  
Vol 10 (22) ◽  
pp. 8016
Author(s):  
Yong-Hyok Kim ◽  
Hak-Young Kim ◽  
Keun-Hyeok Yang ◽  
Jung-Soo Ha
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Bottom Ash ◽  
Target Strength ◽  
Strength Development ◽  
Coarse Aggregates ◽  
Proposed Model ◽  
Reliable Model ◽  
Compressive Strength Development ◽  
Experimental Values

The purpose of this study is to evaluate the workability and mechanical properties of concrete containing bottom ash, which is an industrial byproduct, as an aggregate. Twelve concrete mixtures, including concrete containing bottom ash aggregate (CCBA), are classified into three groups of W/C 0.45, 0.375, and 0.3 according to the target strength. Each group includes four mixtures in which natural aggregate and bottom ash are applied as fine and coarse aggregates according to particular ratios. On the basis of the test results, a reliable model to predict the 28-day compressive strength of CCBA is proposed by applying regression analysis. The proposed model points out that when applying bottom ash as aggregate, the concrete density is lowered, and W/C should be reduced to offset the lowered compressive strength. As a result of comparing experimental values with the existing design code models, it is found that while the fib model accurately predicts compressive strength development and tensile resistance capacity in general, the ACI 318 code overestimates the elastic modulus at the oven-dried density (ρc) range of 1840 kg/m3 and above. Accurate prediction of the mechanical properties of CCBA requires the measurement of additional experimental data that consider W/C and ρc as important parameters.

scholarly journals Effects of the alkaline solution/binder ratio and curing condition on the mechanical properties of alkali-activated fly ash mortars

2017 ◽  
Vol 24 (5) ◽  
pp. 773-782
Author(s):  
Maochieh Chi
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Alkaline Solution ◽  
Drying Shrinkage ◽  
Strength Development ◽  
Initial Surface ◽  
Binder Ratio ◽  
Curing Condition ◽  
Alkali Activated

AbstractThe study investigates the effects of the alkaline solution/binder ratio and the curing condition on the mechanical properties of alkali-activated fly ash (AAFA) mortars. Class F fly ash was used as the raw material, and sodium hydroxide and liquid sodium silicate were used for the preparation of alkaline activators. Three alkaline solution-to-binder ratios (0.35, 0.5, and 0.65) and four different initial curing conditions (curing in air at ambient temperature for 24 h, 30°C for 24 h, 65°C for 12 h, and 85°C for 6 h) were considered. Test results show that AAFA mortars with alkaline solution-to-binder ratio of 0.35 had higher compressive strength, lower drying shrinkage, lower water absorption, and lower initial surface absorption rate than the other mortars. Furthermore, the curing condition influenced the compressive strength development and drying shrinkage of AAFA mortars at early ages. AAFA mortars cured at 65°C for 12 h appeared to have superior mechanical properties. XRD demonstrates that the hydration products of AAFA mortars are mainly amorphous alkaline aluminosilicate gel, which attributed to the compressive strength. Consequently, the alkaline solution-to-binder ratio significantly affects more the mechanical properties than the curing condition based on the presented results.

scholarly journals Effects of Uncrushed Aggregate on the Mechanical Properties of No-Fines Concrete

2018 ◽  
Vol 8 (3) ◽  
pp. 2882-2886 ◽  
Author(s):  
M. A. Memon ◽  
M. A. Bhutto ◽  
N. A. Lakho ◽  
I. A. Halepoto ◽  
A. N. Memon
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Lightweight Concrete ◽  
Aggregate Size ◽  
Unit Weight ◽  
Conventional Concrete ◽  
Major Aspect ◽  
Coarse Aggregates ◽  
Cellular Concrete

Concrete’s self-weight is a major aspect of a structure’s overall weight. Recently, the use of lightweight concrete (no-fines, foamed and cellular concrete) has been increased. Normally no-fines concrete is produced with crushed coarse aggregate of uniform gradation. This study aims to investigate experimentally the effects of the use of uncrushed coarse aggregates on unit weight, compressive and tensile strength of the no-fines (NFC) as well as conventional concrete (CC). In addition, the effects of coarse aggregate size on the mechanical properties were also studied. Four gradations of uncrushed coarse aggregates ranging between (5.5-4.75) mm, (10-4.75) mm, (20-4.75) mm and (25-4.75) mm were used for preparing the concretes. The fixed cement-aggregate ratios of 1:6 (with w/c ratio=0.4) and 1:2:4 (with w/c ratio=0.5) were adopted for NFC and CC respectively. It was found that the gradation of uncrushed coarse aggregate has a significant effect on the mechanical properties of NFC. A maximum of 16% reduction in self-weight of the concrete without fines was obtained, as compared to that with fines. Moreover, the compressive strength of no-fines concrete significantly improved by replacing crushed with uncrushed coarse aggregate. The compressive strength increased by 16% for the batch of (25-4.75) mm.

scholarly journals Effect of Recycled Coarse Aggregate and Bagasse Ash on Two-Stage Concrete

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 556
Author(s):  
Muhammad Faisal Javed ◽  
Afaq Ahmad Durrani ◽  
Sardar Kashif Ur Rehman ◽  
Fahid Aslam ◽  
Hisham Alabduljabbar ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Construction Material ◽  
Strength Reduction ◽  
Recycled Aggregate ◽  
Two Stage ◽  
Conventional Concrete ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates

Numerous research studies have been conducted to improve the weak properties of recycled aggregate as a construction material over the last few decades. In two-stage concrete (TSC), coarse aggregates are placed in formwork, and then grout is injected with high pressure to fill up the voids between the coarse aggregates. In this experimental research, TSC was made with 100% recycled coarse aggregate (RCA). Ten percent and twenty percent bagasse ash was used as a fractional substitution of cement along with the RCA. Conventional concrete with 100% natural coarse aggregate (NCA) and 100% RCA was made to determine compressive strength only. Compressive strength reduction in the TSC was 14.36% when 100% RCA was used. Tensile strength in the TSC decreased when 100% RCA was used. The increase in compressive strength was 8.47% when 20% bagasse ash was used compared to the TSC mix that had 100% RCA. The compressive strength of the TSC at 250 °C was also determined to find the reduction in strength at high temperature. Moreover, the compressive and tensile strength of the TSC that had RCA was improved by the addition of bagasse ash.

scholarly journals Effect of Recycled Coarse Aggregates in Properties of Concrete

2008 ◽  
Vol 3 (4) ◽  
pp. 130-137 ◽  
Author(s):  
R Kumutha ◽  
K Vijai
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Modulus Of Elasticity ◽  
Coarse Aggregate ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Split Tensile Strength ◽  
Coarse Aggregates ◽  
The Cost

The properties of concrete containing coarse recycled aggregates were investigated. Laboratory trials were conducted to investigate the possibility of using recycled aggregates from the demolition wastes available locally as the replacement of natural coarse aggregates in concrete. A series of tests were carried out to determine the density, compressive strength, split tensile strength, flexural strength and modulus of elasticity of concrete with and without recycled aggregates. The water cement ratio was kept constant for all the mixes. The coarse aggregate in concrete was replaced with 0%, 20%, 40%, 60%, 80% and 100% recycled coarse aggregates. The test results indicated that the replacement of natural coarse aggregates by recycled aggregates up to 40% had little effect on the compressive strength, but higher levels of replacement reduced the compressive strength. A replacement level of 100% causes a reduction of 28% in compressive strength, 36% in split tensile strength and 50% in flexural strength. For strength characteristics, the results showed a gradual decrease in compressive strength, split tensile strength, flexural strength and modulus of elasticity as the percentage of recycled aggregate used in the specimens increased. 100% replacement of natural coarse aggregate by recycled aggregate resulted in 43% savings in the cost of coarse aggregates and 9% savings in the cost of concrete.

scholarly journals Examining Polyethylene Terephthalate (PET) as Artificial Coarse Aggregates in Concrete

2020 ◽  
Vol 6 (12) ◽  
pp. 2416-2424
Author(s):  
Erniati Bachtiar ◽  
Mustaan Mustaan ◽  
Faris Jumawan ◽  
Meldawati Artayani ◽  
Tahang Tahang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Polyethylene Terephthalate ◽  
Coarse Aggregate ◽  
Fresh Concrete ◽  
Coarse Aggregates ◽  
Volume Weight ◽  
Concrete Mixtures ◽  
Strength Tests ◽  
Recycled Polyethylene

This study aims to examine the effect of recycled Polyethylene Terephthalate (PET) artificial aggregate as a substitute for coarse aggregate on the compressive strength and flexural strength, and the volume weight of the concrete. PET plastic waste is recycled by heating to a boiling point of approximately 300°C. There are five variations of concrete mixtures, defined the percentage of PET artificial aggregate to the total coarse aggregate, by 0, 25, 50, 75 and 100%. Tests carried out on fresh concrete mixtures are slump, bleeding, and segregation tests. Compressive and flexural strength tests proceeded based on ASTM 39/C39M-99 and ASTM C293-79 standards at the age of 28 days. The results showed that the use of PET artificial aggregate could improve the workability of the concrete mixture. The effect of PET artificial aggregate as a substitute for coarse aggregate on the compressive and flexural strength of concrete is considered very significant. The higher the percentage of PET plastic artificial aggregate, the lower the compressive and flexural strength, and the volume weight, of the concrete. Substitution of 25, 50, 75 and 100% of PET artificial aggregate gave decreases in compressive strength of 30.06, 32.39, 41.73 and 44.06% of the compressive strength of the standard concrete (18.20 MPa), respectively. The reductions in flexural strength were by respectively 19.03, 54.50, 53.95 and 61.00% of the standard concrete's flexural strength (3.59 MPa). The reductions in volume weight of concrete were by respectively 8.45, 17.71, 25.07 and 34.60% of the weight of the standard concrete volume of 2335.4 kg/m3 Doi: 10.28991/cej-2020-03091626 Full Text: PDF

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