Influence of Superplasticizer Quantity on Formation of Micro-Cracks during Setting and Hardening of Concretes by Acoustic Emission Method

Abstract

The acoustic emission phenomenon is directly associated with nucleation of cracks in building materials, therefore the changes result from the volumetric expansion causing formation micro and macro cracking in structure, which we can recognize. The main aim of the article is to compare four ways of curing alkali activated slag mortars by method of acoustic emission. A comprehension of microstructure−performance relationships is the key to true understanding of material behaviour. The results obtained in the laboratory are useful to understand the various stages of micro-cracking activity during the hardening process in quasi-brittle materials such as alkali activated slag mortars and extend them for general practice

Comprehensive Testing Techniques for the Measurement of Shrinkage and Structural Changes of Fine-Grained Cement-Based Composites during Ageing

“…In recent years, the method of acoustic emission (AE) has also been widely used as supplemental measurement in the nondestructive monitoring of changes in a specimen's internal structure during static and dynamic loading tests as well as for the monitoring of the behaviour of composite materials during setting and hardening [11,25,26]. The AE method is considered to be a "passive" nondestructive technique because it usually identifies defects as they develop during the test [27] and allows the monitoring of changes in the behaviour of materials over a long period of time without moving any of their components.…”

Experimental Analysis on Shrinkage and Swelling in Ordinary Concrete

“…The experiments draw on results published within the project GAČR 13-18870S [24][25][26][27]. The purpose of the measurements was to determine volume changes in ordinary concrete and especially to record the progress of early and later-age shrinkage.…”