scholarly journals Effects of carbon nanotubes on expanded glass and silica aerogel based lightweight concrete

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Suman Kumar Adhikary ◽  
Žymantas Rudžionis ◽  
Simona Tučkutė ◽  
Deepankar Kumar Ashish
Keyword(s):  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Silica Aerogel ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Cementitious Materials ◽  
Lightweight Aggregate Concrete ◽  
Multi Wall Carbon Nanotubes ◽  
Sem Image ◽  
Study Results

AbstractThis study is aimed to investigate the effect of carbon nanotubes on the properties of lightweight aggregate concrete containing expanded glass and silica aerogel. Combinations of expanded glass (55%) and hydrophobic silica aerogel particles (45%) were used as lightweight aggregates. Carbon nanotubes were sonicated in the water with polycarboxylate superplasticizer by ultrasonication energy for 3 min. Study results show that incorporating multi-wall carbon nanotubes significantly influences the compressive strength and microstructural performance of aerogel based lightweight concrete. The addition of carbon nanotubes gained almost 41% improvement in compressive strength. SEM image of lightweight concrete shows a homogeneous dispersal of carbon nanotubes within the concrete structure. SEM image of the composite shows presence of C–S–H gel surrounding the carbon nanotubes, which confirms the cites of nanotubes for the higher growth of C–S–H gel. Besides, agglomeration of carbon nanotubes and the presence of ettringites was observed in the transition zone between the silica aerogel and cementitious materials. Additionally, flowability, water absorption, microscopy, X-ray powder diffraction, and semi-adiabatic calorimetry results were analyzed in this study.

Effects of Carbon Nanotubes on the Properties of Lightweight Concrete Prepared With Expanded Glass and Hydrophobic Silica Aerogel

2020 ◽  
Author(s):  
suman kumar adhikary ◽  
Žymantas Rudžionis ◽  
Simona Tučkutė
Keyword(s):  
Carbon Nanotubes ◽  
Silica Aerogel ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Cementitious Materials ◽  
Lightweight Aggregate Concrete ◽  
Sem Image ◽  
Hydrophobic Silica ◽  
Study Results ◽  
Added Water

Abstract This study aimed to study the effect of carbon nanotubes on the properties of expanded glass and silica aerogel based lightweight aggregate concrete. CNTs were dispersed in the polycarboxylate superplasticizer added water by ultrasonication energy for 3 minutes. Combinations of expanded glass (55%) and hydrophobic silica aerogel particles (45%) were used as lightweight aggregates. Study results show that the incorporation of MWCNTs significantly influences the mechanical and microstructural performance of aerogel based lightweight concrete. Almost 41% improvement in compressive strength was gained by the addition of carbon nanotubes. SEM image of lightweight concrete shows CNTs were almost dispersed homogeneously within the concrete structure. SEM image of the composite also shows the presence of the C-S-H structure surrounding the CNTs, that confirms the cites of nanotubes for higher growth of C-S-H. Besides, agglomeration of CNTs and the presence of Ettringites observed in the transition zone between the silica aerogel and cementitious materials. Moreover, flowability, water absorption, microscopy, XRD, and semi-adiabatic calorimetry results were analyzed in this study.

scholarly journals Utilization of Cementitious Materials with Cold-bonded Artificial Aggregate in Concrete

2019 ◽  
Vol 9 (1) ◽  
pp. 385-388
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Cementitious Materials ◽  
Lightweight Aggregate Concrete ◽  
Optimum Level ◽  
Aggregate Concrete ◽  
Glass Fibres ◽  
Granulated Blast Furnace Slag

This article investigates the slump and compressive strength of artificial lightweight aggregate concrete with Ground Granulated Blast Furnace Slag (GGBFS) and Silica Fume with glass fibres. The increase in usage of cement in the construction industry is a concern for ecological deterioration, in this view; artificial aggregates was manufactured with major amount of fly ash and replacement of cement with various industrial by-products in concrete. An optimum level of GGBFS from 10 to 50% and Silica Fume from 2 to 6% with addition of glass fibres was assessed based on compressive strength values. The compressive strength was conducted for 7 and 28Days of water curing on M30 grade lightweight concrete with constant water to cement ratio as 0.45 and 0.2% of Master Gelenium super plasticizer. The conclusions achieved from the compressive strength of concrete containing GGBFS and Silica Fume was increased as the curing time increases. As a result lightweight aggregate concrete with a cement content of 226 kg/m3 develops 37.3 N/mm2 compressive strength.

scholarly journals Efficiency factor and modulus of elasticity of lightweight concrete with expanded clay aggregate

2010 ◽  
Vol 3 (2) ◽  
pp. 195-204 ◽  
Author(s):  
W.G Moravia ◽  
A. G. Gumieri ◽  
W. L. Vasconcelos
Keyword(s):  
Compressive Strength ◽  
Modulus Of Elasticity ◽  
Large Scale ◽  
Lightweight Concrete ◽  
Weight Ratio ◽  
Lightweight Aggregate ◽  
Normal Weight ◽  
Lightweight Aggregate Concrete ◽  
Empirical Methods ◽  
Normal Weight Concrete

Nowadays lightweight concrete is used on a large scale for structural purposes and to reduce the self-weight of structures. Specific grav- ity, compressive strength, strength/weight ratio and modulus of elasticity are important factors in the mechanical behavior of structures. This work studies these properties in lightweight aggregate concrete (LWAC) and normal-weight concrete (NWC), comparing them. Spe- cific gravity was evaluated in the fresh and hardened states. Four mixture proportions were adopted to evaluate compressive strength. For each proposed mixture proportion of the two concretes, cylindrical specimens were molded and tested at ages of 3, 7 and 28 days. The modulus of elasticity of the NWC and LWAC was analyzed by static, dynamic and empirical methods. The results show a larger strength/ weight ratio for LWAC, although this concrete presented lower compressive strength.

scholarly journals Experimental Research on High Temperature Resistance of Modified Lightweight Concrete after Exposure to Elevated Temperatures

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Ke-cheng He ◽  
Rong-xin Guo ◽  
Qian-min Ma ◽  
Feng Yan ◽  
Zhi-wei Lin ◽  
...  
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Modification Method ◽  
Superior Mechanical Properties ◽  
Axial Compressive Strength ◽  
Crushed Limestone

In order to improve the spalling resistance of lightweight aggregate concrete at high temperature, two types of modified materials were used to modify clay ceramsite lightweight aggregates by adopting the surface coating modification method. Spalling of the concrete specimens manufactured by using the modified aggregates was observed during a temperature elevation. Mass loss and residual axial compressive strength of the modified concrete specimens after exposure to elevated temperatures were also tested. Concrete specimens consisting of ordinary clay ceramsites and crushed limestone were manufactured as references for comparison. The results showed that the ordinary lightweight concrete specimens and the crushed limestone concrete specimens were completely spalled after exposure to target temperatures above 400°C and 1000°C, respectively, whereas the modified concrete specimens remained intact at 1200°C, at which approximately 25% to 38% of the residual compressive strength was retained. The results indicated that the modified lightweight concrete specimens have exhibited superior mechanical properties and resistance to thermal spalling after exposure to elevated temperatures.

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.

Mechanical Properties of Lightweight Alum Sludge Aggregate Concrete

2015 ◽  
Vol 754-755 ◽  
pp. 413-416 ◽  
Author(s):  
Nur Quraatu’ Aini Mohd Rajin ◽  
Roszilah Hamid
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Content Increase ◽  
Split Tensile Strength ◽  
Aggregate Concrete ◽  
Alum Sludge ◽  
Better Than

Disposal of alum sludge (AS) in such an economical and environmental friendly way is a major challenge that water treatment plants around the globe had to deal with. AS cannot be dumped into landfills as it contains heavy metals which are harmful to the environment. In this study, alum sludge is utilised as partial replacements (0, 5 and 10%) of natural granite coarse aggregate (by mass) to form a lightweight concrete. The water/cement ratio is 0.65. The water absorption of the alum sludge is 22.06%. The slump, density, compressive strength and split tensile strength of the lightweight alum sludge aggregate concrete (LASAC) reduce as the AS aggregate content increase. The density of the 10% AS aggregate concrete is 2185.3 kg/m3. The compressive strength reduced from 25.6 MPa to 16.7 MPa and 14.2 MPa at 0, 5 and 10% replacement of AS aggregate respectively. The 2.18 MPa tensile strength of the control concrete reduced to 1.53 MPa at 10% replacement of AS aggregate. But as for the flexural strength, it increases from 5.42 MPa for the control up to 5.55 MPa and 5.63 MPa for 5 and 10% replacement of AS aggregate respectively. Results show that strength of alum sludge lightweight aggregate concrete is better than lightweight crumb tyre aggregate concrete and is at par with oil palm coconut shell aggregate concrete.

scholarly journals The Structural Characteristics of Lightweight Aggregate Concrete Beams

2019 ◽  
Vol 27 (2) ◽  
pp. 64-73
Author(s):  
Sajjad abdulameer Badar ◽  
Laith Shakir Rasheed ◽  
Shakir Ahmed Salih
Keyword(s):  
Compressive Strength ◽  
Ultimate Load ◽  
Lightweight Concrete ◽  
Concrete Beams ◽  
Lightweight Aggregate ◽  
Normal Weight ◽  
Lightweight Aggregate Concrete ◽  
Dry Density ◽  
Aggregate Concrete ◽  
Clay Bricks

This paper aims to investigate the structural behavior of reinforced lightweight concrete beams. Attapulgite aggregate and crushed clay brick aggregate were used as coarse lightweight aggregate to produce structural lightweight aggregate concrete with 25 Mpa and 43.6 Mpa cube compressive strength and 1805 Kg/m3 and 1977 Kg/m3 oven dry density respectively. The result of reinforced lightweight concrete beams compared with reinforced normal weight concrete beams, which have 50.5 Mpa cylinder compressive strength and 2317 Kg/m3 oven dry density. For each type of concrete two reinforced concrete beams with (1200 mm length × 180 mm height × 140 mm width), one of them tested under symmetrical two-points load STPL (a/d = 2.2) and another one tested under one-point load OPL (a/d=3.3) at 28 days. The experimental program shows that a structural lightweight aggregate concrete can be produced by using Attapulgite aggregate with 25 MPa cube compressive strength and 1805 Kg/m3 oven dry density and by using crushed clay brick aggregate with 43.6 MPa cube compressive strength and 1977 Kg/m3 oven dry density. The weight of Attapulgite aggregate concrete and crushed clay bricks aggregate concrete beam specimens were lower than normal weight aggregate concrete beams by about 20.56% and 13.65% respectively at 28 days.  As for the ultimate load capacities of beam specimens, the ultimate load of Attapulgite aggregate concrete beams tested under STPL were lower than that of crushed clay bricks aggregate concrete beams and normal weight aggregate concrete beams by about 4.85% and 5% respectively. While the ultimate load capacities of reinforced Attapulgite concrete beams tested under OPL were lower than that of reinforced crushed clay bricks aggregate concrete beams and reinforced normal weight aggregate concrete beams by about 10.3% and 10.5% respectively. Finally, Attapulgite aggregate concrete and crushed clay bricks aggregate concrete showed ductility and toughness less than that of Normal weight aggregate 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 Testing of nutmeg shell as a lightweight concrete material in terms of volume weight and compressive strength value

2021 ◽  
Vol 3 (2) ◽  
pp. 113-118
Author(s):  
Budiman Budiman
Keyword(s):  
Compressive Strength ◽  
Lightweight Concrete ◽  
Research Result ◽  
Lightweight Aggregate ◽  
Laboratory Research ◽  
Lightweight Aggregate Concrete ◽  
Dead Weight ◽  
Concrete Material ◽  
Volume Weight ◽  
Lightweight Structure

Lightweight concrete can be defined as a type of concrete which includes an expanding agent in that it increases the volume of the mixture while giving additional qualities such as nailibility and lessened the dead weight. The nutmeg shell has the characteristics of light and hard skin testure so that it has the potential to be used as a material for lightweight concrete. The purpose of this study is to determine the aggregate characteristic value and the compressive strength value of concrete using the DOE (department of environment) method and referring to standards SNI. Variation of use nugmet shell toward the weight volume of concrete is 10%, 20%, 30%, 40% and 50%. This research is a sample-based laboratory research and analysis of aggregate characteristics and concrete compression test. The research result shows that the use of nutmeg skin as a coarse aggregate material in the concrete mixture affects the volume weight of the concrete. The weight of the concrete gets lighter along with the higher the percentage used. The average volume weight obtained was 1810.06 kg / m3. Based on the weight of the concrete sample, it is classified as light structure, includes concrete with low density and includes lightweight aggregate concrete. The compressive strength values for the characteristics of concrete at a composition of 10%, 20% and 30% were obtained at 28.42 kg/cm2, 31.65 kg/cm2 and 32.68 kg/cm2 which increased while the use of nutmeg shells at 40% and 50% compositions was obtained. values of 29.09 kg/cm2 and 27.38 kg/cm2 decreased at the age of 28 days. The increase in the value of the compressive strength of concrete (fck') occurred starting at the composition of 20% and 30% at 10.20% and 13.03% and begin to decrease at the composition of 50% by 3.65%. Lightweight concrete from nutmeg shells has an weight of 1810,06 kg/m3 and a maximum compressive strength value of 3,2 MPa so that the concrete is in the category lightweight structure.

scholarly journals MODIFICATION OF PROPERTIES OF STRUCTURAL LIGHTWEIGHT CONCRETE WITH STEEL FIBRES / LENGVOJO BETONO SAVYBIŲ MODIFIKAVIMAS PLIENINĖMIS FIBROMIS

2011 ◽  
Vol 17 (1) ◽  
pp. 36-44 ◽  
Author(s):  
Lucyna Domagała
Keyword(s):  
Compressive Strength ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Normal Weight ◽  
Rheological Parameters ◽  
Lightweight Aggregate Concrete ◽  
Significant Deterioration ◽  
Steel Fibres ◽  
Concrete Mixtures ◽  
Weight One

Structural lightweight aggregate concrete (SLWAC) is an alternative building material to normal-weight one, due to its ability to reach a relatively high compressive strength at still significantly lower density. Nevertheless, the application of lightweight aggregate instead of normal-weight one to concrete must result in deterioration of some characteristics of the composite. One of the methods of improving SLWAC properties is incorporation of fibers into concrete. This paper focuses on the influence of steel fibres on modification of properties of structural lightweight concrete with sintered fly ash aggregate. Two different concrete mixtures, producing various levels of matured composite density and compressive strength, were modified with three dosages of fibers: 30, 45 and 60 kg/m3. The applied amounts did not result in significant deterioration of the rheological parameters of concrete mixtures. Despite relatively low volume content of fibres, a considerable increase of flexural and tensile splitting strength was observed. Fibres also improved concrete shrinkage as well as post-peak deformability in uni-axial compression. The effect of steel addition on compressive strength proved to be dependent on specimen type. Nevertheless, it was not as crucial as in the case of the above characteristics. However, the modulus of elasticity of SLWAC was not affected by fibre addition. Santrauka Konstrukcinis su lengvaisiais užpildais betonas (SLWAC) yra normalaus svorio statybinių medžiagų alternatyva, turinti mažesnį tankį ir gebėjimą pasiekti gana didelį gniuždomąjį stiprį. Nepaisant to, lengvieji užpildai, naudojami vietoj normalaus svorio užpildų, realiai gali pabloginti kai kurias kompozito savybes. Vienas iš lengvojo betono SLWAC savybių tobulinimo būdų yra plieninių fibrų įterpimas į betono sudėtį. Šiame darbe aptariamas plieninių fibrų poveikis konstrukcinio lengvojo betono su lakiaisiais pelenais savybėms. Tikslui pasiekti buvo parinktos pagal tankį ir gniuždomąjį stiprį dvi skirtingos betono sudėtys su skirtingais (30, 45 ir 60 kg/m3) plieninių fibrų tankiais. Paruošti bandiniai buvo naudoti gniuždomajam stipriui ir kitoms savybėms nustatyti. Tyrimų rezultatai parodė, kad plieninių fibrų priedas nepablogino reologinių betono mišinio rodiklių. Nepaisant palyginti mažo fibrų kiekio, labai padidėjo bandinių lenkiamasis ir tempiamasis stipris. Fibros taip pat pagerino deformacines betono savybes. Gauto kompozito gniuždomasis stipris iš dalies priklausė nuo naudojamų plieninių fibrų charakteristikų. Tačiau plieninių fibrų priedas nepakeitė SLWAC tamprumo modulio.

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