![]() In November 1929, the industrial production of Ytong blocks began. In the early 1920s, Eriksson experimented with different samples of gas concrete and put the mixtures in an autoclave to speed up the curing process. It was invented by the Swedish architect, Johan Axel Eriksson, assistant professor at the Royal Institute of Technology in Stockholm. Probably the most famous and first type of autoclaved gas concrete was Ytong. During the 1920s and 1930s, many different types of lightweight concrete were developed, e.g., Durisol, Siporex, Argex, and Ytong. In the end the conclusion of the chapter will be drawn.Ĭoncrete is a relatively heavy building material therefore many experiments have been conducted throughout the twentieth century to decrease its weight without impairing other properties. Further a case study of LWC made of LWA will be conducted and presented for a better understanding of the properties of LWC. In the present chapter after the discussion about the lightweight concrete and its properties, we will study about the compressive strength of LWC and the methods for evaluation and prediction of compressive strength of LWC. It is also observed that the elastic modulus of LWC is lower than the equivalent strength of NWC, but when considering the deflection of a slab or beam, this is counteracted by the reduction in dead load. However, there are benefits in using LWC such as reduction in dead load that results in slight reduction in the depth of a beam or slab. LWC are also less stiff than the equivalent NWC. For two specimens of concrete with the same compressive strength, but one made of LWC and the other one made of NWC, the tensile strength, ultimate strains, and shear strengths are all lower in LWC than NWC, while the amount of creep and shrinkage is higher for LWC. With the reduction of the concrete density, the properties of the concrete change fundamentally. There are several benefits with using LWAC such as improved thermal specifications, better fire resistance, and dead load reduction which results in lower cost of labor, transportation, formworks, etc., especially in precast concrete construction industry. LWC with compressive strength less than 17 MPa is also considered as NSLWC. LWC made of a material with lower densities and higher air voids in the cement paste are considered as nonstructural lightweight concrete (NSLWC) and will most likely be used for its insulation and lower weight properties. ![]() The practical range for the density of SLWC is between 14 kg/m 3. To be considered as structural lightweight concrete (SLWC), the minimum 28-day compressive strength and maximum density are 17 MPa and 1840 kg/m 3, respectively. Lightweight aggregate concretes (LWAC) can be used for structural applications, according to the American Concrete Institute (ACI). The author hopes that the present chapter and the discussed case study on LWC would attract the attention of researchers to the importance of LWC in the future of construction industry.ġ.4 Structural and nonstructural lightweight concrete In the end, it can be observed that the properties of LWC depend on the properties of the used LWA, and therefore for each specific type of lightweight aggregate, a brand new equation will be required for prediction of concrete compressive strength. The experimental program includes about 150 specimens, incorporating different unit weight for the entire specimens. A case study has been designed and conducted including an experimental program on the LWC made of expanded glass aggregate. ![]() In addition to conventional compression test, a nondestructive test (NDT) method will be used to assess the compressive strength of a variety of lightweight concrete mixes. Compressive strength and density of LWC are the main points of interest in this chapter. Therefore, after a brief background of lightweight concrete, different types of LWC will be introduced and then LWC made of lightweight aggregates (LWA) will be specifically discussed. This chapter has been prepared with the hope that its readers will become interested in lightweight concrete (LWC).
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