1.1 Lightweight aggregate concrete (LWAC)

There are a variety of lightweight aggregates that can be used in the production of LWAC, such as natural materials, like volcanic pumice, and the thermal-treated natural raw materials like expanded glass, clay, shale, etc. LECA is an example of expanded clay and Poraver is an example of expanded glass aggregates. There are also other types, which are aggregates made of industrial by-products such as fly ash, like Lytag. The final properties of the LWC will depend on the type and mechanical properties of LWA used in the concrete mixture.

methods for evaluation and prediction of compressive strength of LWC. 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 end the conclusion of the chapter

Concrete is a relatively heavy building material; therefore many experiments have been conducted throughout the twentieth century to decrease its weight without impairing other properties. During the 1920s and 1930s, many different types of lightweight concrete were developed, e.g., Durisol, Siporex, Argex, and Ytong. Probably the most famous and first type of autoclaved gas concrete was Ytong. It was invented by the Swedish architect, Johan Axel Eriksson, assistant professor at the Royal Institute of Technology in Stockholm. 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. In November 1929, the industrial production of Ytong blocks began. The name combines the y of Yxhult, the town where the first Swedish factory was located, and the end of betong, the Swedish word for concrete. The material was very popular in Sweden from 1935 onward, with a true breakthrough immediately after World War II, when it became one of the most important building materials in the country. Also, the manufacturing process was exported to other countries such as Norway, Germany, the UK, Spain, Poland, Israel, Canada, Belgium, and even Japan. The autoclaved gas concrete Siporex was developed in Sweden in 1935. The LWAC, Argex, was first produced in Denmark in 1939 under the international brand name Leca. Starting with an annual production in Copenhagen of

, the total production throughout Europe had increased by 1972 to

nearly 6 million m<sup>3</sup> per year (adopted from postwar building materials "postwa

The later type of LWC which is called LWAC is one of the most popular one among them and from that time until today has been the subject of many research works around the word. Even today there are many ongoing extensive research programs on SLWC and NSLWC made of LWA. In the present chapter, we focus on LWAC, and for the case study, we will discuss a part of the ongoing research of the author on LWAC [1]. Categorized examples of the research works conducted

In 2013, a research was conducted on producing concrete containing recycled aggregates obtained from crushed structural and nonstructural lightweight concrete [2]. The mechanical properties of this concrete were investigated. Concrete compositions made of recycled lightweight concrete aggregates (RLCA) were measured for their compressive strength, modulus of elasticity, tensile strength, and abrasion resistance. The influence of the properties of the aggregates on concrete properties were discussed including concrete density, compressive strength, structural efficiency, splitting tensile strength, modulus of elasticity, and abrasion resistance. This research proved that it is possible to produce structural recycled lightweight concrete from crushed, structural, and nonstructural LWC with densities below

will be drawn.

20,000 m<sup>3</sup>

51

rbuildingmaterials.be").

recently have been discussed below:

2.1 LWC including recycled lightweight aggregate

2. Background of lightweight concrete

Compressive Strength of Lightweight Concrete DOI: http://dx.doi.org/10.5772/intechopen.88057
