Foam concrete

"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..."

"FC has been quickly promoted as construction materials for tunnels and underground works. Its excellent self-flowing capacity can be used to fill voids, sink holes, disused sewage pipes, abandoned subways, and so on. The low and controlled self-weight makes it capable for load reduction or liner elements in tunnel and metro systems..."

"Tan et al.... performed an investigation on compression deformation properties of FC used as liner element for the purpose of further explaining stress and strain response. The experimental results indicated that the of FC increases with density and confining pressure, whereas the modulus of elasticity has a positive correlation only with densities regardless of confining pressure. And no notable correlation was observed between peak strain and density, but peak strain increases with confining pressure."

"Tikalsky et al.... studied the freeze-thaw durability of cellular concrete and proposed an improved freeze-thaw test method. They reported that depth of absorption was considered as a critical predictor in developing freeze-thaw-resistant concrete, which will contribute to promote effectiveness in terms of using FC as insulation material for tunnels in cold regions."

"Sun et al... explored the influence of different foaming agents on compressive strength, drying shrinkage, and workability of FC, which will be helpful to determine specification and implementation details."

"Amran et al... reviewed the composition, preparation process, and properties of FC..."

"[T]he focus of... Ramamurthy et al... is to classify literatures on foaming materials, foaming agents, cement, fillers, mix proportion, production methods, fresh and hardened properties of FC, etc."