The Phenomenon of Cracking in Cement Concretes and Reinforced Concrete Structures: The Mechanism of Cracks Formation, Causes of Their Initiation, Types and Places of Occurrence, and Methods of Detection—A Review

Abstract

Cracks and cavities belong to two basic forms of damage to the concrete structure, which may reduce the load-bearing capacity and tightness of the structure and lead to failures and catastrophes in construction structures. Excessive and uncontrolled cracking of the structural element may cause both corrosion and weakening of the adhesion of the reinforcement present in it. Moreover, cracking in the structure negatively affects its aesthetics and in extreme cases may cause discomfort to people staying in such a building. Therefore, the following article provides an in-depth review of issues related to the formation and development of damage and cracking in the structure of concrete composites. It focuses on the causes of crack initiation and characterizes their basic types. An overview of the most commonly used methods for detecting and analyzing the shape of microcracks and diagnosing the trajectory of their propagation is also presented. The types of cracks occurring in concrete composites can be divided according to eight specific criteria. In reinforced concrete elements, macrocracks depend on the type of prevailing loads, whereas microcracks are correlated with their specific case. The analyses conducted show that microcracks are usually rectilinear in shape in tensioned elements; in shear elements there are wing microcracks with straight wings; and torsional stresses cause changes in wing microcrack morphology in that the tips of the wings are twisted. It should be noted that the subject matter of microcracks and cracks in concrete and structures made of this material is important in many respects as it concerns, in a holistic approach, the durability of buildings, the safety of people staying in the buildings, and costs related to possible repairs to damaged structural elements. Therefore, this problem should be further investigated in the field of evaluation of the cracking and fracture processes, both in concrete composites and reinforced concrete structures.

Unlocking the strength: the predictions of silicon carbide fracture toughness revealed through data-driven approach

“…Silicon carbides (SiC), with merits of low density, high strength, high hardness, as well as excellent high temperature oxidation resistance [1,2] are widely used within machinery, chemical industry, aerospace and military and other fields, especially under harsh environments with high temperature and severe corrosions [3][4][5]; making it as a very attractive structural material. Fracture, with various modes, is one common failure manner of brittle materials (such as concrete composites, rocks) when suffering tensile loads, which has been assessed by different experimental approaches and modified through composite or/and reinforced form [6,7]. The micro-defects, initiated near the macro-crack tip due to local high stress concentration, or generated during the material preparation and processing processes, play a significant role on crack growth behaviors that influence the fracture properties [8].…”

3D Change Detection Method for Exterior Wall of LNG Storage Tank Supported by Multi‐Source Spatial Data

“…[ 6–8 ] LNG storage tank operators can put corrective procedures in place to reduce risk as much as possible when flaws and potential dangers are promptly identified. [ 9–11 ] Therefore, for assuring security, structural integrity, and long‐term viability, measurement and analysis of deformation in the external wall of an LNG storage tank are crucial.…”

Examination of water absorption of low volume fly ash concrete (LVFAC) under water immersion conditions

“…It should also be noted that concretes made with the participation of SCMs allow not only to reduce CO 2 emissions generated during the burning of the Portland clinker [44,45], but also significantly reduce the amount of energy necessary to carry out this technological process [46]. The broad group of SCMs includes both traditional mineral additives such as: fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBFS) , metakaolin (MK) [47][48][49][50][51][52][53], volcanic pumice powder [54], or eggshells [55] as well as nanoadditives, which have been used to a large extent for several years [56][57][58][59][60][61][62][63][64][65]. Moreover, municipal sewage sludge are also used [66,67].…”