scholarly journals Optimal Mix Design and Quality Properties of 50 MPa Self-Consolidating Lightweight Concrete

2020 ◽  
Vol 20 (6) ◽  
pp. 135-142
Author(s):  
Se-Hee Hong ◽  
Jin-Seok Choi ◽  
Jaehoon Lee ◽  
Young-Soo Yoon
Keyword(s):  
Coarse Aggregate ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Performance Criteria ◽  
Dry Density ◽  
Fine Aggregate ◽  
Quality Properties ◽  
Air Content ◽  
Optimal Mix ◽  
Filling Capacity

In this study, basic data were used to quantitatively determine the initial properties of self-consolidating lightweight concrete by analyzing various characteristics, such as air content, workability, segregation resistance, filling capacity, air/dry density, and strength according to the incorporating ratio of lightweight aggregate. With the exception of Mixture (LF75-LC100) that uses 100% lightweight coarse aggregate (LC) and 75% lightweight fine aggregate (LF), all the mixtures satisfied the performance criteria for workability, segregation resistance, and filling capacity, as suggested in the JSCE, and air/dry density, as suggested in the Concrete Standard Specification. The compressive strength of all the variables, except the LF75-LC100, was measured to be at least 50 MPa, but the strength decreased in a manner similar to that depicted in previous research when LC was incorporated. The results of the above experiments indicated that 100% of the LC and 50% of the LF was the optimal mix for self-consolidating lightweight concrete.

scholarly journals Sustainable Green Lightweight Concrete Containing Plastic-Based Green Lightweight Aggregate

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3304
Author(s):  
Fahad K. Alqahtani
Keyword(s):  
Natural Resources ◽  
Coarse Aggregate ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Normal Weight ◽  
Plastic Waste ◽  
Unit Weight ◽  
Lightweight Aggregate Concrete ◽  
Dry Density ◽  
Study Results

Nowadays the environment and its natural resources face many issues, related to the depletion of natural resources beside the increase in environmental pollution resulted from uncontrolled plastic waste disposal. Therefore, it is important to find effective and feasible solutions to utilize these wastes, such as using them to produce environmentally friendly green concrete. In this study, plastic-based green lightweight aggregates (PGLAs) containing PET plastic waste and by product additives were developed, and their subsequent physical and mechanical properties were compared with those of reference aggregates. Then, green lightweight aggregate concrete mixes (GLACs) were produced at 100% replacement of normal weight and lightweight coarse aggregate with developed PGLAs; and their fresh, hardened, microscopic and durability-related properties were compared to those of control mixes. Study results revealed that the unit weight of PGLAs were 21% to 29% less than that of normal coarse aggregate. Additionally, PGLAs had low water absorption that varied between 1.2% and 1.6%. The developed aggregates had 45% higher strength compared to that of lightweight coarse aggregate. Study results confirmed that structural green lightweight aggregate concretes (GLACs), that satisfied the dry density, compressive and splitting tensile strength requirements specified in ASTM C330, were feasibly produced. Finally, GLACs had low-to-moderate chloride penetration in accordance with ASTM C1202, thus it can be used in those areas exposed to the risk of chloride attack.

scholarly journals The influence of OPC and PPC on compressive strength of ALWA concrete

2018 ◽  
Vol 195 ◽  
pp. 01021
Author(s):  
Fedya Diajeng Aryani ◽  
Tavio ◽  
I Gusti Putu Raka ◽  
Puryanto
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Normal Weight ◽  
Structural Members ◽  
Concrete Composition ◽  
Normal Weight Concrete ◽  
To Come ◽  
Seismic Forces

Lightweight concrete is one of the options used in construction in lieu of the traditional normal-weight concrete. Due to its lightweight, it provides lighter structural members and thus, it reduces the total weight of the structures. The reduction in weight resulting in the reduction of the seismic forces since its density is less than 1840 kg/m3. Among all of the concrete constituents, coarse aggregate takes the highest portion of the concrete composition. To produce the lightweight characteristics, it requires innovation on the coarse aggregate to come up with low density of concrete. One possible way is to introduce the use of the artificial lightweight aggregate (ALWA). This study proposes the use of polystyrene as the main ingredient to form the ALWA. The ALWA concrete in the study also used two types of Portland cements, i.e. OPC and PPC. The ALWA introduced in the concrete comprises various percentages, namely 0%, 15%, 50%, and 100% replacement to the coarse aggregate by volume. From the results of the study, it can be found that the compressive strength and the modulus of elasticity of concrete decreased with the increase of the percentage of the ALWA used to replace the natural coarse aggregate.

scholarly journals Production of lightweight Geopolymer concrete using artificial local lightweight aggregate

2018 ◽  
Vol 162 ◽  
pp. 02024
Author(s):  
Waleed Abbas ◽  
Wasan Khalil ◽  
Ibtesam Nasser
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Experimental Tests ◽  
Pulse Velocity ◽  
Dry Density ◽  
Geopolymer Concrete

Due to the rapid depletion of natural resources, the use of waste materials and by-products from different industries of building construction has been gaining increased attention. Geopolymer concrete based on Pozzolana is a new material that does not need the presence of Portland cement as a binder. The main focus of this research is to produce lightweight geopolymer concrete (LWGPC) using artificial coarse lightweight aggregate which produced from locally available bentonite clays. In this investigation, the binder is low calcium fly ash (FA) and the alkali activator is sodium hydroxide and sodium silicate in different molarities. The experimental tests including workability, fresh density, also, the compressive strength, splitting tensile strength, flexural strength, water absorption and ultrasonic pulse velocity at the age of 7, 28 and 56 days were studied. The oven dry density and thermal conductivity at 28 days age are investigated. The results show that it is possible to produce high strength lightweight geopolymer concrete successfully used as insulated structural lightweight concrete. The 28-day compressive strength, tensile strength, flexural strength, dry density, and thermal conductivity of the produced LWGPC are 35.8 MPa, 2.6MPa, 5.5 MPa, 1835kg/m3, and 0.9567 W/ (m. K), respectively.

scholarly journals Novel Core-Shell Non-Sintered Lightweight Aggregate Concrete for Better Properties in Wallboard

2021 ◽  
Author(s):  
Chaoming PANG ◽  
Xinxin MENG ◽  
Chunpeng ZHANG ◽  
Jinlong PAN
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Insulation ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Dry Density ◽  
Core Shell ◽  
Aggregate Concrete ◽  
The Core

Abstract Shrinkage of foam concrete can easily cause cracking and thus makes it difficult for a manufacturer to maintain quality. The density of lightweight aggregate concrete is too high to meet specifications for lightweight and thermal insulation for wallboard. Two types of concrete with dry density in the range 1000–1200 kg/m3 for use in wallboard were designed and prepared using foam and lightweight aggregate. The properties of porous lightweight aggregate concrete with core-shell non-sintered lightweight aggregate were compared with sintered lightweight aggregate concrete along with several dimensions. The two aggregates were similar in particle size, density, and strength. The effects of each aggregate on the workability, compressive strength, dry shrinkage, and thermal conductivity of the lightweight concrete were analyzed and compared. Pore structures were determined by mercury intrusion porosimetry and X-ray computed tomography. Compressive strength ranged from 7.8 to 11.8 MPa, and thermal conductivity coefficients ranged from 0.193 to 0.219 W/m/K for both types of concrete. The results showed that the core-shell non-sintered lightweight aggregate bonded better with the paste matrix at the interface transition zone and had a better pore structure than the sintered lightweight aggregate concrete. Slump flow of the core-shell non-sintered lightweight aggregate concrete was about 20% greater than that of the sintered lightweight aggregate concrete, 28d compressive strength was about 10% greater, drying shrinkage was about 10% less, and thermal conductivity was less. Porous lightweight aggregate concrete using core-shell non-sintered lightweight aggregate performs well when used in wallboard because of its low density, high thermal insulation, and improved strength.

scholarly journals Influence of Ash and Coconut Shell Against Compressive Strength and Permeability Characteristics of Pervious Concrete

2021 ◽  
Vol 12 (3) ◽  
pp. 4129-4138
Author(s):  
Suwendy Arifin Et.al
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Lightweight Concrete ◽  
Waste Material ◽  
Pervious Concrete ◽  
Coconut Shell ◽  
Fine Aggregate ◽  
Permeability Characteristics ◽  
Fine Aggregates ◽  
Reduced Density

Pervious concrete or non-fine concrete is a simple form of lightweight concrete made by eliminating the use of fine aggregates. As a result of not using fine aggregate in pervious concrete, then created a cavity filled with air and water can be passed. This cavity resulted in reduced density of the concrete as well as the reduced amount of area that needs to be covered by cement paste, thereby reducing the compressive strength. To increase the compressive strength of pervious concrete, in this study will utilize waste material. The waste material is the cocnut shell ash and coconut shell to strengthen the coarse aggregate bonds, so it is expected to increase the compressive strength along with the increase in permeability. Thus, in this study will replace part of the coarse aggregate with coconut shell with percentage 0%, 2,5%, 5%, 7,5%, 10% and partially replace cement with coconut shell ash with percentage 0%, 2,5%, 5%, 7,5%

scholarly journals Influence of Coarse Aggregate Gradation on the Mechnical Properties of Concrete, Part I: No-Fines Concrete

2019 ◽  
Vol 9 (5) ◽  
pp. 4612-4615 ◽  
Author(s):  
Z. A. Tunio ◽  
F. U. R. Abro ◽  
T. Ali ◽  
A. S. Buller ◽  
M. A. Abbasi
Keyword(s):  
Coarse Aggregate ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Fine Sand ◽  
Minimum Size ◽  
Unit Weight ◽  
Lightweight Aggregate Concrete ◽  
Total Load ◽  
Aggregate Gradation ◽  
Coarse Aggregates

It is well-accepted fact that in concrete construction, the self-weight of the structure is a major part of its total load. Reduction in the unit weight of the concrete results in many advantages. The structural lightweight aggregate concrete (LWAC) of adequate strength is now very common in use. In frame structures, the partition walls are free of any loading, where the construction of these non-structural elements with lightweight concrete of low strength would lead to the subsequent reduction of the overall weight of the structure. No-fines concrete is one of the forms of lightweight concrete and it is porous in nature. It can be manufactured similarly as normal concrete but with only coarse aggregates and without the sand. Thus, it has only two main ingredients; the coarse aggregates and the cement. The coarse aggregates are coated with a thin cement paste layer without fine sand. This is a detailed experimental study carried on NFC with fixed cement to the aggregate proportion of 1:6 with w/c 0.40 ratio. In this study, coarse aggregate of  various gradations (7-4.75) mm, (10-4.75) mm, (10-7) mm, (13-4.74) mm, (10-7) mm, (13-4.75) mm, (13-10) mm, (13-7) mm, (20-4.75) mm, (20-7) mm, (20-10) mm, (20-13) mm, are used, where prefix and suffix show the maximum and minimum size of the aggregate. The cube and cylinder specimens of standard sizes are cast to determine the compressive strength and splitting tensile and the specimens are cured in water up to the age of testing (28 days).

scholarly journals Experimental Study on Light Weight Concrete Using Coconut Shell and Fly Ash

2022 ◽  
Vol 10 (1) ◽  
pp. 752-758
Author(s):  
Barkha Verma
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Coarse Aggregate ◽  
Lightweight Concrete ◽  
Fresh Concrete ◽  
Industrial Wastes ◽  
Coconut Shell ◽  
Fine Aggregate ◽  
Concrete Production ◽  
Coconut Shells

Abstract: Aggregates provide volume at low cost, comprising 66% to 78% of the concrete. With increasing concern over the excessive exploitation of natural and quality aggregates, the aggregate produced from industrial wastes and agricultural wastes is the viable new source for building material. This study was carried out to determine the possibilities of using coconut shells as aggregate in concrete. Utilizing coconut shells as aggregate in concrete production not only solves the problem of disposing of this solid waste but also helps conserve natural resources. In this paper, the physical properties of crushed coconut shell aggregate were presented. The fresh concrete properties such as the density and slump and 28 days compressive strength of lightweight concrete made with coconut shell as coarse aggregate were also presented. The findings indicate that water absorption of the coconut shell aggregate was high about 24% but crushing value and impact value were comparable to that of other lightweight aggregates. The average fresh concrete density and 28days cube compressive strength of the concrete using coconut shell aggregate 1975kg/m3 and 19.1 N/mm2 respectively. It is concluded that crushed coconut shell is suitable when it is used as a substitute for conventional aggregates in lightweight concrete production. Keywords: Coarse Aggregate, Cement, Concrete, Fly Ash, Coconut shell Aggregate, Water, Compressive Strength, Workability, Fine Aggregate.

scholarly journals Optimum Oil Palm Shell Content as Coarse Aggregate in Concrete Based on Mechanical and Durability Properties

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Mehdi Maghfouri ◽  
Payam Shafigh ◽  
Muhammad Aslam
Keyword(s):  
Oil Palm ◽  
Coarse Aggregate ◽  
Lightweight Concrete ◽  
Drying Shrinkage ◽  
Lightweight Aggregate ◽  
High Strength ◽  
Normal Weight ◽  
Concrete Mixture ◽  
Palm Shell ◽  
Oil Palm Shell

Oil palm shell (OPS) is a biosolid waste in palm oil industry in the tropical countries which could be used as aggregate in concrete mixture. Since 1984, OPS has been experimented as natural lightweight aggregate in research studies to produce lightweight concrete (LWC). Medium and high-strength LWCs using OPS as coarse aggregate were successfully produced. However, higher drying shrinkage and lower mechanical properties for concretes containing higher volume of OPS are reported in previous studies. Therefore, OPS is not fit to be used as full coarse aggregate in concrete mixture and therefore, there should be an optimum OPS content in concrete. In this study, in a normal-weight concrete, normal coarse aggregate was replaced with OPS from zero to 100% with an interval of 20%. Tests such as slump, density, compressive strength in different curing conditions, splitting tensile strength, initial and final water absorptions, and drying shrinkage of cured and uncured specimens were conducted to find out optimum OPS content in concrete. From the test results, it could be summarized that OPS content should not exceed 60% of total volume of coarse aggregate.

Properties of Lightweight Concrete Masonry Units Made from Lightweight Aggregates

2010 ◽  
Vol 150-151 ◽  
pp. 1588-1594
Author(s):  
Chao Wei Tang ◽  
Kuo Haung Fan ◽  
Wen Po Tsai ◽  
How Ji Chen
Keyword(s):  
High Performance ◽  
Coarse Aggregate ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Normal Weight ◽  
Filling Ratio ◽  
National Standards ◽  
Unit Weight ◽  
Concrete Masonry ◽  
Research Findings

In the paper the properties of concrete masonry unit (CMU) made from sedimentary lightweight aggregate (LWA) were investigated. The main variables include water to cementitious material ratio (W/CM), filling ratio of paste or mortar in voids between coarse aggregate particles (Fv), filling ratio of sand in mortar (Fm), and cement replacement level by slag (Sc). Test results of representative CMU specimens show that unit weight ranged from 1585 to 1743 kg/m3, which was 30-25% lower than that for a normal weight CMU (2300 kg/m3); compressive strengths ranged from 8.4 to 18.7 MPa; water absorption was found to vary between 0.05 to 0.13 g/cm3; and thermal conductivity ranged from 0.27 to 0.41 W/mK. The research findings demonstrate that the use of sedimentary LWA as coarse aggregate in various concrete mixtures could produce high performance lightweight CMU, which comply with the requirements of Chinese National Standards (CNS) standards.

scholarly journals Microstructure of Structural Lightweight Concrete Incorporating Coconut Shell as a Partial Replacement of Brick Aggregate and Its Influence on Compressive Strength

2021 ◽  
Vol 13 (13) ◽  
pp. 7157
Author(s):  
Hamidul Bari ◽  
Md. Safiuddin ◽  
Md. Abdus Salam
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Lightweight Concrete ◽  
Coconut Shell ◽  
Partial Replacement ◽  
Dry Density ◽  
Sem Images ◽  
Air Content ◽  
Compressive Strength Of Concrete ◽  
Imagej Software

In this study, coconut shell aggregate (CSA) was used in brick aggregate concrete (BAC) to produce structural lightweight concrete. Various BACs containing CSA (CSBACs) were prepared based on the volumetric mix ratio of 1:1.5:3 (cement:fine aggregate:coarse aggregate). CSA was used substituting 0−15% of brick aggregate (BA) by weight. The concrete mixes were designed based on the weight-based water to cement (w/c) ratios of 0.45, 0.50, and 0.55. All the freshly mixed concretes were tested for their workability with respect to slump. In addition, the freshly mixed concretes made with the w/c ratio of 0.50 were examined for their wet density and air content. The hardened concretes were tested for their dry density, compressive strength, and microstructural characteristics (e.g., microcrack, micropore, fissure). The microstructure of CSBACs was investigated by a scanning electron microscope (SEM). In addition, the fissure width between the cement paste and CSA was measured from the SEM images using “ImageJ” software. The correlation between the compressive strength and fissure width of CSBAC was also examined. Test results showed that the air content of CSBACs including 5–15% CSA was higher than that of the control concrete (0% CSA). In addition, the density and compressive strength of concrete decreased with the increased CSA content. Above all, the most interesting finding of this study was the presence of fissures in the interfacial transition zone between the cement paste and CSA of CSBAC. The fissure width gradually increased with the increase in CSA content and thus decreased the compressive strength of concrete. However, the fissure width decreased with the increased curing age of concrete and therefore the compressive strength of CSBAC was enhanced at later ages. Moreover, a good correlation between the compressive strength and fissure width of CSBAC was observed in this study.

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