2.1 LWC including recycled lightweight aggregate

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

2000 kg/m<sup>3</sup> . Improvements in mechanical properties can be seen when the LWA is replaced with RLCA. The study concluded that recycled lightweight aggregate is a potential alternative to conventional LWC.

2.5 LWC including expanded glass aggregates and expanded clay aggregates

mixtures containing EGA and ECA are 1458–2278 and 1588–2302 kg/m<sup>3</sup>

(EGA) in concrete is still in its early stages.

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

3. Nondestructive testing methods

The capability of defect detection

properties of concrete.

Method based

on

Table 1.

53

An experimental investigation on the compressive strength and durability of LWC with fine expanded glass (FEG) and expanded clay aggregates (ECA) using different micro-fillers including ground quartz sand and silica fume was conducted in 2018 [7]. Based on their research, ECA is one of the most popular aggregates for SLWC, and using this aggregate is important for sustainable development in the construction industry. The relationships between compressive strength and density of concrete mixtures with different proportions of LWA were explored. The effects of fine LWA on density and compressive strength of LWAC were also analyzed. They could reach to compressive strengths of 39.5–101 MPa for the mixtures containing EGA and 43.8–109 MPa for mixtures containing ECA. The density of the

tively. Different compressive strength-density relationships were obtained for LWC containing EGA and LWC containing ECA even though the compositions had the same amount of cement, water to cement ratio, micro filler, and total volume of LWA. While understanding the basic mechanical properties (density and compressive strength) of concrete containing LWA such as ECA and EGA was the main goal of this study, it was concluded that the application of expanded glass aggregate

As in the present book, compressive strength of concrete is the main subject of

Nondestructive testing (NDT) methods are widely used in the investigation of the mechanical properties and integrity of concrete structures. As seen in Table 1, provided by AASHTO [8], the following techniques are used for detecting defects in

abrasion

Chemical attack

Voids in grout

Cracking Scaling Corrosion Wear and

Strength N N P N P N Sonic F N Gb N N N Ultrasonic G N F N P N Magnetic N N F N N N Electrical N N G N N N Nuclear N N F N N N Thermography N Gb Gc N N N Radar N Gb Gc N N N Radiography F N F N N F G = good; F = fair; P = poor; N = not suitable; Gb = beneath bituminous surfacing; Gc = detects delamination.

Capability of investigating techniques for detecting defects in concrete structures in field use [8].

discussion; later in this chapter, we will discuss a case study on compressive strength of a specific type of LWC containing EGA implementing a NDT method in addition to the conventional compression test. Therefore in the next section, we will briefly talk about the usage of NDT in the evaluation of compressive strength and

, respec-
