Engineering

"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."

"Incorporation of fibres leads to only a slight increase in the compressive strength of foamed concrete; however, it can significantly improve the (up to 4 times), tensile strength (up to 3 times) and impact strength (up to 6 times)."

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

"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..."

"[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."

"Amran et al... Fadila et al... Kang... Fernando et al... and Portal et al... produced foamed concrete for use in wall panels. Rum et al... used foamed concrete as a component in a profiled composite slab. Kadela et al.., Drusa et al.., Tian et al... and Lee at al... used foamed concrete in a pavement or floor structure to transmit a load on a subsoil, including weak soil. Moreover, foamed concrete has been used in building foundations..."

"[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..."

"[F]oamed concrete has the potential to become a mainstream material that uses waste material successfully as a replacement for cement or fine aggregate..."

"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."

"The components of foamed concrete (type of cement... water... water/binder ratio... additives... and admixtures...) have a significant effect on its properties..."

"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..."

"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."

"[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..."

"Foamed concrete was made using the pre-foaming method with physical foaming or mixing and the foaming method with chemical foaming..."

"Foamed concrete is characterized by its ability to flow, self-compact and self-level as well excellent thermal and acoustic insulation..."

"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."

"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..."

"Foamed concrete (FC) is classified as lightweight concrete with a density ranging from 280 to 1800 kg/m³... and with a minimum of 20% of air pore volume in the cementitious mix..."

"[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%..."

"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."

"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..."

"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..."

"The compressive strength ranges from 0.21 to 10.34 MPa for a density of 300 to 1600 kg/m³ ...[in] typical application."

"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."

"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..."

"This study aims to assess the properties of foamed concrete with a density of around 500, 700, 800 and 1000 kg/m³ formed by using a synthetic polymer-based foaming agent. The distribution of pores, wet and dry density and compressive strengths were evaluated. In addition, the creep deformations... were measured."

"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."

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

"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..."

"[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)..."

"Foamed concrete with higher densities (700 and 800 kg/m³) showed similar characteristics of pores, which were different from those of samples with a density of 500 kg/m³."

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

"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..."

"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..."

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

"equal to 5.9... 5.1... 3.8... and 1.4... MPa was obtained for foamed concrete with a density of [1000, 800, 700 and 500] kg/m3, respectively. The obtained compressive strengths were higher than those found in the literature..."

"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."

"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."

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

"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."

"Incorporation of randomly oriented fibres into foamed concrete can improve load transfer in different directions, and increases due to the creation of an elastoplastic composite... in load-bearing structures..."

"Considering that fibreglass also increases mechanical strength, this is an important factor in FC’s stability... High-strength foamed concrete is obtained by introducing (PP) fibre into the raw mix... Many of the currently used fibres have been investigated, including PP... blend of polypropylene with glass... ... ... steel... palm oil, coconut... and other fibres... introduced in an amount of 0.2–1.5% volume of the concrete mixture; however, in this article, the fibre content ranges upper limit has been extended to 5%. As an alternative to traditional reinforcement, one strategy with composite mesh and mesh combined with fibre has also been studied for lightweight foamed concrete (LWFC)..."

"To increase FC’s mechanical characteristics, the water-binding ratio w/b is usually maximally reduced, as well as the use of finely dispersed ic raw materials as a replacement for fine aggregate..."

"Using synthetic and natural fibres (glass and carbon ones) in FRFC has shown excellent durability properties with reduced drying shrinkage, high modulus of elasticity and increased mechanical strength..."