Architecture

"[T]he use of fibres (e.g., synthetic, metallic and natural fibres) as reinforcement is reported as an effcient material added into the fibre-reinforced FC (FRFC) matrix... to bridge the cracks... [reduce] shrinkage crack[s], to enhance load transfer and to improve the hardened properties by altering the characteristic brittle behavior [in]to elastic–plastic behavior, particularly, the flexural and tensile properties."

"The fibre matrix interface and matrix densification can deliver a greater load carrying capacity of FC reliant on the toughness of the fibres. The FRFC prolongs post-crack ductility even... [with] repeating loading cycles."

"This paper reviews the production of FC, type of foam agents, method of foaming generation, type of fibres used and factors affecting the mechanical properties of FRFC. [It also provides] a critical review on the properties and behaviors of FRFC as well as... research development trends to generate... insights into the potential applications of FRFC as suitable concrete materials... robust FRFC composites, for modern buildings and civil engineering applications... to draw a more complete picture of the current state-of-the-art."

"Axel Erikson was the first to patent -based FC technology in the year 1923... The characteristics, behaviour and structural applications of FC have been widely investigated..."

"FC is reportedly proved to be superior to conventional concrete mainly due to its lower density, which helps in reducing the static construction loads, foundation volume, labour, transportation, and exploitation expenses..."

"Many countries like the United Kingdom, Germany, Philippines, Turkey, and Thailand have made the use of FC in many construction applications..."

"The bubbles’ volume varies from 6% to 35% of the total final mixture in most of FC applications..."

"Foam agents are inorganic and organic compounds... in pellet or powder foam. Organic agents are , hydrazocarbonamide, benzenesulfonyl hydrazide, dinitrosopentamethylene tetramine, toluenesulfonyl hydrazide, benzene sulfonyl , and barium azodicarboxylate. While inorganic agents are NaHCO3, NH4HCO3, (NH4)2CO3, and Ca(N3)2... foams are used as insulation spray for air-sealing buildings. stabilizer is added to enhance its slurry viscosity which consists of 20% of 40% of and 40% of hydroxypropyl methyl cellulose... [T]he various foam agents are available in E-markets worldwide."

"The chemical foamer is ordinarily protein-based, hydrolysed protein, detergents, synthetic, , soaps of resin, and glue resins... The protein foamers form in a more grounded and enclosed cell of air-void structure, which allows the incorporation of a more prominent volume of bubble and gives a higher steady bubble network. In contrast, the synthetic ones abdicate more prominent extension and hence lower density... [T]he extreme use of chemical foam volume causes a decrease in flow, density and mechanical properties of FC... However, FC’s flow is considerably influenced by the time of mixing, showing that the lengthy mixing can result in the damage of the enclosed cell of air-voids by plummeting the air content..."

"Reportedly, FC’s mechanical properties are commonly dependent on the volume of foam content instead of its dependence over the proportion of water and cement..."

"Fibre-reinforced concrete (FRC) is one containing fibrous material that improves its structural solidity..."

"Basalt fibre is cut from a continuous basalt fibre with a diameter of 17 μm, 2.5 times superior in tensile strength to superior steel. Average fibre length: 6 to 24 mm. Recommendations for the dosage of basalt fibre: 1 kilogram per 1 cubic meter of mortar or concrete. It is necessary to introduce it into the mix with water, after stirring the fibre until it is evenly distributed in the water, it is necessary to slightly increase the mixing time (up to 5–10 min) for uniform distribution in volume."

"For fibreglass concrete, an alkali-resistant (AR) fibre should be used."

"PVA fibres have a higher tensile strength [1300 MPa] than [other] synthetic[s] and are relatively economical... Due to its low density... the fibre is ideal for foamed concrete... the is 25 GPa..."

"[P]olypropylene fibre, despite the low modulus of elasticity (1.5–10 GPa), has relatively high durability... an even lower density than PVA... [and is] ideal for foam concrete. The... tensile strength is 240–760 MPa and the ultimate elongation is 15–80%..."

"[F]ibres content should be controlled within 5% to achieve optimum concrete behaviour where excessive fibres may reduce the concrete strength."

"As claimed by Lim et al... finer... aggregate size may increase the strength of FC... As the particle size grading decreased, from passing through 2.36 mm sieve to 0.60 mm and 0.10 mm sieve, the strength has an increasing trend... With finer aggregate, the workability also increases and reduces the use of compaction that potentially bursts the bubble inside concrete paste."

"Silica fume has been found to benefit concrete properties [145], especially compressive strength and durability. It was added to FRFC and was found to have a 25% increment, at most, in compressive strength..."

"With the same quantity of addition, and specimens have higher compressive strength than silica fume... [N]ano-silica also have been investigated... The 4% nano-silica was found to have more excellent mechanical properties, durability and microstructure than plain FC and 15% silica fume... Silica fume was eFFectively enhanced the flexural, compressive and tensile strength and durability with a combination of waste marble material... [T]o enhance LWFC properties, apart from traditional materials, such as FA or SF... the recycled components like the slag of various types... or glass... have also been included in the LWFC concrete matrix... [T]he pozzolans may increase the concrete strength and its durability..."

"FC is obtained from mixing base mix (normally mortar) with preformed foam (diluted foam agent with high pressure). ...FC consists of cement as binders, sand as aggregates, water, and foams. As a consideration of economic and performance enhancements, many researchers... [introduced] additives or replacements to the FC, such as fly ash... silica fume... superplasticizer... fibres, and others. There is no specific method to determine the mixing proportions. However, Kearley... proposed the calculation of mixing the proportions by the target density method, and other researchers have practiced this."

"Fibre-reinforced foam concrete mixture is poured into molds without mechanical compaction, so it must have self-sealing ."

"For optimization various performances such as consistency, rheology and workability, segregation and bleeding should be considered... These parameters mainly depend on the water/cement ratio, supplementary cementitious materials, aggregates, s, foam agents, and the type and concentration of fibre."

"[T]he mixture’s components must be precisely calculated to improve the rheology and consistency of FRFCC, attain self-sealing behaviors, and enhance the adhesion and cohesion between the foaming agent and the cementitious filler. One of the main features influencing the rheology and texture of fresh FRFCC is the mixture’s water content. Another main factor is the fibre density... the adding of light fibre negatively influences the constancy of the mixture. Besides, the rheology of FRFC worsens with excess foam due to the higher air volume, while the incorporation of SP improved the flow rate. ...[T]he "Portland cement—silica-containing additive-complex modifiers" system can significantly reduce and create easily compacted fibre-reinforced foamed concrete mixtures."

"The introduction of fibre somewhat reduces workability. The fibres large specific surface absorbs more of the cementitious mortar around the fibres and, consequently, increases the viscosity of concrete, which contributes to a slight reduction in... spreadability. However, with proper FRFC mix... improvement in workability can be achieved by introducing the optimum fibre amount."

"The principle of the segregation and bleeding (water separation) test is that after sampling, the concrete mixture is left for 15 min... After that, the upper part of the sample is poured onto a sieve with a mesh size of 5 mm. After two minutes... [t]he stratification coefficient is calculated as the mixture ratio above the sieve to [that below it]."

"[[w:Superplasticizer|[S]uperplasticizers]], if used to reduce w/c, do not cause separation or water separation. The use of a clogging micro filler (for example, finely ground limestone or quartz sand) helps to reduce... water separation... [T]he micro filler [may create] an additional "stability framework," which increases... resistance to segregation..."

"[I]nclusion of fibres [having] more than one type or more than one size... [has been] recognized as hybrid fibres."

"[C]ompressive strength decreases exponentially when concrete’s density decreases... FC’s compressive strength commonly decreases gradually as the entrapped bubbles increased; however, its strength may be enhanced by adding fibres... [F]ibres can enhance its hardened [physical] properties (including... toughness and elasticity)..."

"[O]verall strengths were mainly influenced by the factor of combined water/cement and air/cement ratio..."

"The objective of this study is to develop structural fibered foamed concrete by the addition of polypropylene fiber, , and . Foamed concrete was obtained by replacing sand with fly ash. The properties of the foamed concrete were enhanced with polypropylene fiber and fine silica fume."

"Structural fibered foamed concrete with dissimilar densities of foamed concrete (1000, 1300, 1600, and 1900 kg/m³) [62, 81, 100, 119 lb/ft³] is essential for examining compressive, flexural and splitting tensile strengths, drying shrinkage and creep."

"Fine silica fume and polypropylene fiber considerably promoted the hardened strength... [P]olypropylene fiber significantly enhanced the tensile strength and increased the creep resistance and drying shrinkage."

"[S]tructural fibered foamed concrete can be used as a substitute lightweight concrete material for the production of structural concrete applications... today."

"The neat cement with fine sand was used in the fabrication of a lightweight FC with uniformly distributed micro- or macroscopic discrete air cells..."

"FC provides unique advantages, such as thermal and acoustic insulation and resistance to fire and termite attack, lowers cost in construction, and produces... eco-friendly structures..."

"Generally, FC is designed to achieve a low compressive strength around 1–10 MPa [150 to 1,500 psi] and can be applicable in filling voids and restoring trenches but cannot be used in the construction of any structural member... To achieve the desired strength of at least 25 MPa [3,600 psi]... different innovative solutions... are economically and environmentally admissible..."

"[S]mall water-to-binder (w/b) ratio and the inclusion of (SF), ultrafine powder of silica and (FA) as an alternative of sand is recommended in the production of high-strengths FC..."

"A number of studies produced FC with compressive strength of around 50 MPa [7,300 psi] by applying special curing condition and described the relationships among strength, density, and porosity..."

"The present paper attempts to develop structural fibered foamed concrete (SFFC) with 10–70 MPa [1,500-7,300 psi] compressive strength and 1000–1900 kg/m³ [62-119 lb/ft³] density."

"Ordinary (OPC)... was used to prepare the specimens... Dry and un-compacted SF with a SiO2 content of 91.9% was used... A residue of approximately 1.56% was obtained after sieving the residue through a 45 Am sieve. ...Class F FA was used in accordance with ASTM C 618... PP fiber with a 100 μm (dia.) and 10 mm (length) was used... A [protein-based] foam agent... with an aerated density of 80 kg/m³... after diluting... [with] water... in a ratio of 1∶40 [by volume] was used... A -based super-plasticizer was applied... The dosage of the super-plasticizer and the flow of premix paste were low... [A] cohesive state was observed in the final FC mixture, in which the cementitious particle appeared... wrapped by the foam. ...[O]nly one type of middle-east sand [ 1.72] was used... spherical and smooth-surfaced..."

"Practically, a sufficient flow range in a premixed paste is a proof of the effective production of FC. When the value of flow seen was lesser than the limit, the mixes of the developed premixed paste and foam was considered in-cohesive. The binders seemed to be covered by air bubbles, which collapsed afterwards. [W]hen the value of flow was greater than the limit, seclusion happened and foam bubbles inclined to collapse."

"[A]fter 7 days of curing, the concrete without SF attained approximately 65%–80% of [compressive] strength at 28-day[s]... the specimens encompassing SF gained approximately 80%–95%... [I]n FC without SF, the 90-day strength was approximately 75%–90% of the conforming... strength. [S]pecimens encompassing SF gained around 80%–95% of the equivalent 90-day strength. Therefore, the FC with FA can gain strength over a long period."

"[L]ightweight FC material can develop strength of equal to 60 MPa [8,700 psi] with a density of approximately 60%–70% of the traditional concrete density."

"For a specified volume of foam, the PP fiber significantly improved the hardened strength. ...This advantage was also observed in the FC specimens with SF. Nevertheless... addition of PP fiber condensed the flowability of mix. Thus, we increased dosage... 0.8% fiber content was the best... level on the basis of a swap between performance enhancement and flowability loss."

"FC is a type of cement mortar containing cement, water, and stable and homogeneous foam introduced using a suitable foaming agent... regarded as self-compacting materials..."

"Other academic terms describing this material are lightweight cellular concrete, low-density foam concrete, or cellular lightweight concrete, etc..."

"The textural surface and microstructural cells make it widely used in the fields of the thermal insulation... sound absorbance... and fire resistance..."

"A great number of environmentally friendly buildings using FC as nonstructural members have been built in recent years... It is also used for bridge filling to eliminate differential settlement... In addition, the applications for prefabricated components production... building foundation... and airport buffer system are also reported..."

"Foam concrete has been commonly used in construction applications in different countries such as Germany, USA, Brazil, UK, and Canada..."

"This material has renewed interests in terms of underground engineering. This is the requirement of underground structure to control the overlying dead load... whereas the controllable density and low self-weight... could be effectively used for reducing the dead load. Other properties, such as seismic resistance, ideal coordinated deformation capacity, and easy pumping...enhance the popularity of this material..."