scholarly journals Fibre-Reinforced Foamed Concretes: A Review

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4323 ◽  
Author(s):  
Mugahed Amran ◽  
Roman Fediuk ◽  
Nikolai Vatin ◽  
Yeong Huei Lee ◽  
Gunasekaran Murali ◽  
...  
Keyword(s):  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Sound Insulation ◽  
Plastic State ◽  
High Porosity ◽  
Load Bearing ◽  
Foaming Agents ◽  
Pozzolanic Material ◽  
Aramid Fibres ◽  
Foamed Concrete

Foamed concrete (FC) is a high-quality building material with densities from 300 to 1850 kg/m3, which can have potential use in civil engineering, both as insulation from heat and sound, and for load-bearing structures. However, due to the nature of the cement material and its high porosity, FC is very weak in withstanding tensile loads; therefore, it often cracks in a plastic state, during shrinkage while drying, and also in a solid state. This paper is the first comprehensive review of the use of man-made and natural fibres to produce fibre-reinforced foamed concrete (FRFC). For this purpose, various foaming agents, fibres and other components that can serve as a basis for FRFC are reviewed and discussed in detail. Several factors have been found to affect the mechanical properties of FRFC, namely: fresh and hardened densities, particle size distribution, percentage of pozzolanic material used and volume of chemical foam agent. It was found that the rheological properties of the FRFC mix are influenced by the properties of both fibres and foam; therefore, it is necessary to apply an additional dosage of a foam agent to enhance the adhesion and cohesion between the foam agent and the cementitious filler in comparison with materials without fibres. Various types of fibres allow the reduction of by autogenous shrinkage a factor of 1.2–1.8 and drying shrinkage by a factor of 1.3–1.8. Incorporation of fibres leads to only a slight increase in the compressive strength of foamed concrete; however, it can significantly improve the flexural strength (up to 4 times), tensile strength (up to 3 times) and impact strength (up to 6 times). At the same time, the addition of fibres leads to practically no change in the heat and sound insulation characteristics of foamed concrete and this is basically depended on the type of fibres used such as Nylon and aramid fibres. Thus, FRFC having the presented set of properties has applications in various areas of construction, both in the construction of load-bearing and enclosing structures.

Effects of Fibre on Drying Shrinkage, Compressive and Flexural Strength of Lightweight Foamed Concrete

2012 ◽  
Vol 587 ◽  
pp. 144-149 ◽  
Author(s):  
Hanizam Awang ◽  
Md Azree Othuman Mydin ◽  
Ahmad Farhan Roslan
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Lightweight Concrete ◽  
Drying Shrinkage ◽  
Test Results ◽  
Polypropylene Fibres ◽  
Load Bearing ◽  
Foamed Concrete

The present study covers the use of fibre in lightweight foamed concrete (LFC) to produce the lightweight concrete for use in construction of non-load bearing elements. LFC with 600, 1000 and 1400 kg/m3 density were cast and tested. Polypropylene fibres with different percentage were used into LFC and the resulting products were compared to normal LFC. Compressive strength, flexural strength and drying shrinkage tests were carried out to evaluate the mechanical properties up to 180 days. The addition of fibres in LFC showed no contribution on compressive strength but improvement in the flexural and shrinkage test results.

Effects of Various Additives on Drying Shrinkage, Compressive and Flexural Strength of Lightweight Foamed Concrete (LFC)

2012 ◽  
Vol 626 ◽  
pp. 594-604 ◽  
Author(s):  
Ahmad Farhan Roslan ◽  
Hanizam Awang ◽  
Md Azree Othuman Mydin
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Drying Shrinkage ◽  
Polypropylene Fibre ◽  
Microstructure Formation ◽  
Pozzolanic Material ◽  
Curing Period ◽  
Foamed Concrete

This paper presents an investigation on lightweight foamed concrete (LFC) with different type of additives. LFC with 600, 1000 and 1400 kg/m3 density were cast and tested. Fly ash, lime and polypropylene fibre were used on each density with different percentages. All the additives effects were compared with normal LFC as control mix. Mechanical properties of LFC were evaluated with several tests up to 180 days. The results show that the drying shrinkage, compressive strength and flexural strength are affected by the hydration process of each additive in the harden LFC. Fly ash as pozzolanic material helps to strengthen the LFC, though it needs longer curing period to achieve ultimate strength. Lime gives slight contribution to strength as detail investigation on microstructure formation will give clear answer on how the mechanical properties were affected. The addition of polypropylene contributes to flexural strength and shrinkage of LFC. Polypropylene fibre only contributes to compressive strength at low LFC density.

scholarly journals The performance of ultra-lightweight foamed concrete incorporating nanosilica

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Mohamed Abd Elrahman ◽  
Pawel Sikora ◽  
Sang-Yeop Chung ◽  
Dietmar Stephan
Keyword(s):  
Wall Thickness ◽  
Probabilistic Approach ◽  
Drying Shrinkage ◽  
Dry Density ◽  
Optimal Dosage ◽  
X Ray ◽  
Mechanical And Physical Properties ◽  
Fresh State ◽  
Foamed Concrete ◽  
The Stability

AbstractThis paper aims to investigate the feasibility of the incorporation of nanosilica (NS) in ultra-lightweight foamed concrete (ULFC), with an oven-dry density of 350 kg/m3, in regard to its fresh and hardened characteristics. The performance of various dosages of NS, up to 10 wt.-%, were examined. In addition, fly ash and silica fume were used as cement replacing materials, to compare their influence on the properties of foamed concrete. Mechanical and physical properties, drying shrinkage and the sorption of concrete were measured. Scanning electron microscopy (SEM) and X-ray microcomputed tomography (µ-CT) and a probabilistic approach were implemented to evaluate the microstructural changes associated with the incorporation of different additives, such as wall thickness and pore anisotropy of produced ULFCs. The experimental results confirmed that the use of NS in optimal dosage is an effective way to improve the stability of foam bubbles in the fresh state. Incorporation of NS decrease the pore anisotropy and allows to produce a foamed concrete with increased wall thickness. As a result more robust and homogenous microstructure is produced which translate to improved mechanical and transport related properties. It was found that replacement of cement with 5 wt.-% and 10 wt.-% NS increase the compressive strength of ULFC by 20% and 25%, respectively, when compared to control concrete. The drying shrinkage of the NS-incorporated mixes was higher than in the control mix at early ages, while decreasing at 28 d. In overall, it was found that NS is more effective than other conventional fine materials in improving the stability of fresh mixture as well as enhancing the strength of foamed concrete and reducing its porosity and sorption.

scholarly journals Reinforcing Mechanisms of Coir Fibers in Light-Weight Aggregate Concrete

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 699
Author(s):  
Xiaoxiao Zhang ◽  
Leo Pel ◽  
Florent Gauvin ◽  
David Smeulders
Keyword(s):  
Cement Hydration ◽  
Natural Fibers ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Hydration Reaction ◽  
Light Weight ◽  
Limited Information ◽  
Aggregate Concrete ◽  
Coir Fibers ◽  
Light Weight Aggregate

Due to the requirement for developing more sustainable constructions, natural fibers from agricultural wastes, such as coir fibers, have been increasingly used as an alternative in concrete composites. However, the influence of coir fibers on the hydration and shrinkage of cement-based materials is not clear. In addition, limited information about the reinforcing mechanisms of coir fibers in concrete can be found. The goal of this research is to investigate the effects of coir fibers on the hydration reaction, microstructure, shrinkages, and mechanical properties of cement-based light-weight aggregate concrete (LWAC). Treatments on coir fibers, namely Ca(OH)2 and nano-silica impregnation, are applied to further improve LWAC. Results show that leachates from fibers acting as a delayed accelerator promote cement hydration, and entrained water by fibers facilitates cement hydration during the whole process. The drying shrinkage of LWAC is increased by adding fibers, while the autogenous shrinkage decreases. The strength and toughness of LWAC are enhanced with fibers. Finally, three reinforcement mechanisms of coir fibers in cement composites are discussed.

Effects of triethanolamine on autogenous shrinkage and drying shrinkage of cement mortar

2021 ◽  
Vol 304 ◽  
pp. 124620
Author(s):  
Hui Liu ◽  
Hui Lin ◽  
Xiaoyong Liu ◽  
Jian Wang ◽  
Xiaofan Pang ◽  
...  
Keyword(s):  
Cement Mortar ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage

scholarly journals WATER ABSORPTION AND DRYING SHRINKAGE OF RECYCLED FOAMED AGGREGATE CONCRETE

2018 ◽  
Vol 30 (3) ◽  
Author(s):  
Chai Teck Jung ◽  
Tang Hing Kwong ◽  
Koh Heng Boon
Keyword(s):  
Water Absorption ◽  
Absorption Rate ◽  
Drying Shrinkage ◽  
Casting Process ◽  
Concrete Specimen ◽  
Sieve Analysis ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Water Absorption Rate ◽  
Foamed Concrete

Abstract: This paper presents some experimental results and discusses the used of recycled foamed aggregates as natural coarse aggregates replacement in producing concrete. The physical properties of recycled foamed aggregates concrete were investigated. The properties studied are water absorption and drying shrinkage from the concrete early ages until the periods of 56 days. The 100 mm x 100 mm cube specimen was used to study the water absorption at the age of 7, 28 and 56 days. Meanwhile, the 100 mm x 100 mm x 300 mm length prism had been casted and used for drying shrinkage test for recycled foamed aggregates concrete. The foamed aggregates was produced from crushing recycled foamed concrete blocks. It were coated with cement paste to reduce its water absorption ability during casting process. Superplasticizer was used to maintain the workability of fresh concrete with a slump vary between 50 mm to 100 mm. The physical tests were conducted on recycled foamed aggregates to determine their initial properties such as loose bulk density, sieve analysis and water absorption rate. Recycled foamed aggregate concretes were produced with varied water cement ratio. The results obtained indicated that the linear elastic relationship between water cement ratio and water absorption rate. The higher the water cement ratio of concrete specimen will obtained higher water absorption rate. Vice versa, the density is low for drying shrinkage. The water absorption decreased while drying shrinkage becomes more stabilized over curing period.

scholarly journals Synthesis of Pectiniform Polyurethane-Modified Polycarboxylate and Its Preliminary Application in Ultrahigh-Performance Concrete

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Shuncheng Xiang ◽  
Yingli Gao
Keyword(s):  
Silica Fume ◽  
Negative Impact ◽  
Raw Materials ◽  
Synthesis Method ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Isophorone Diisocyanate ◽  
Initiation System ◽  
Dry Shrinkage ◽  
Preliminary Application

In this paper, modified polyurethane prepolymer was synthesized by the segmental synthesis method using isophorone diisocyanate (IPDI), hydroxyl-terminated silicone, and polyether glycol dimethylolpropionic acid as raw materials. After that, pectiniform polycarboxylate, of which side chains were in roughly the same polymerization degree and main chains were in different lengths, was synthesized at normal temperature in the complex initiation system of H2O2, APS, sodium bisulfite, and Vc. Then, compared with commercial Sika polycarboxylate, their applications in ultrahigh-performance concrete (HUPC), including flowability, strength, drying shrinkage, and autogenous shrinkage, were investigated. The results showed that, due to the molecular structure of polyorganosiloxane, the synthesized polycarboxylate could be better dispersed. Dosage of silica fume could effectively improve the compressive strength of UHPC, while slag had a certain negative impact on its strength. Incorporation of slag and silica fume could effectively reduce the dry shrinkage of UHPC.

Structural Characterization of Foamed Composite Structural Insulated Panel with Coir for Load Bearing Wall Application

2018 ◽  
Vol 934 ◽  
pp. 222-226
Author(s):  
Jericson H. Advincula ◽  
Dustin Glenn C. Cuevas ◽  
Allan Dave A. Dela Cruz ◽  
John Paul D. Carreon
Keyword(s):  
Flexural Strength ◽  
Structural Characterization ◽  
Exterior Wall ◽  
Load Bearing Capacity ◽  
Maximum Increase ◽  
Load Bearing ◽  
Permanent Formwork ◽  
Foamed Concrete ◽  
Design Loads

Permanent formwork building system is a method that uses the formwork as a contributor to the load bearing capacity of the structure. This study characterized the proposed foamed composite structural insulated panel (CSIP) with coir for load bearing wall application in low rise construction. The percentage of coir in foamed concrete that could significantly increase the compressive and flexural strength of the panel considering the effect of coir to the workability of the foamed concrete were determined. The results showed that the samples with 0.5% coir had the maximum increase in its compressive and flexural capacity and further addition of coir decreases its capacities. The results also showed that it could carry the required design loads. Moreover, using Euler’s buckling equation for the effect of slenderness, the panel could be used as exterior wall for a height of 2m, 3m, and 4m and as interior wall for a height of 2m and 3m. It can be concluded that the proposed panel could be used as a load bearing wall in low rise construction.

scholarly journals Minimizing Drying Shrinkage and Enhancing Impermeability of Foam Concrete Modified with Epoxy Resin

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Jianqing Gong ◽  
Ke Li
Keyword(s):  
Surface Energy ◽  
Pore Size ◽  
Epoxy Resin ◽  
Average Pore Size ◽  
Drying Shrinkage ◽  
Maximum Level ◽  
High Porosity ◽  
Foam Concrete ◽  
Average Pore ◽  
Internal Pore Structure

Relatively high drying shrinkage and permeability were two of the major challenges associated with foam concrete (FC), primarily due to its high porosity nature. This study was aimed at reducing the drying shrinkage and improving the impermeability of FC by blending and modifying it with epoxy resin (EP). Extensive laboratory testing yielded an optimum content of 4.0% EP, corresponding to a minimum drying shrinkage rate of 1.47 mm/m, which was 48% lower than that of the unmodified FC. At this optimum dosage of 4.0% EP, the permeability pressure was at a maximum level of 1.4 MPa, whereas the permeability coefficient was at its lowest value of 0.75 × 10−9  mm/h. Internal pore structure and EP distribution were characterized using the scanning electron microscopy and indicated that a microgrid structure of the FC was formed internally, featuring an increase in the number of pores, a reduction in the average pore size, and a uniform pore size distribution. Similarly, surface energy measurements using the tensiometry method yielded maximum surface energy values at 4.0% EP content, which could be used to explain the reduced drying shrinkage and the enhanced impermeability characteristics of the modified FC.

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