Concrete Deterioration Statistical Analysis

Introduction

Concrete refers to a composite material that constitutes of aggregates in a bonded manner with the help of fluid cement that contributes to its hardening (Alexander & Mindess 2010). Despite the hardening nature of the concrete material, at times it tends to undergo deterioration due to certain factors responsible for it. Therefore, there are continuous debates concerning premature deterioration of concrete structures and relative values of concrete materials. Some believe that this problem may have its root cause from the unreliable specifications, cases of poor design details and use of poor human skills while handling works related to concrete (Alexander & Mindess 2010). However, the corrosion of steel component in concrete is the most critical reason for degradation of concrete material, especially the reinforced types, in the entire world. Currently, the economic loss that occurs due to concrete degradation is a major problem in industrialized nations. Following this instance, this paper will evaluate the causes and consequences of concrete degradation in a wider context and conduct the statistical analysis of the problem.

Literature Review

Concrete Deterioration

The most trending cause of concrete degradation is the corrosion of reinforcing steel and other additional metals (Alexander & Mindess 2010). As the steel undergoes corrosion, the development of rust material finds its way in the larger part of the steel component of concrete. It causes expansion process on the concrete thereby resulting in development of tensile stresses in the concrete. Due to these tensile stresses in the concrete, it begins to crack, delaminate and spall.

Since the deterioration of concrete material relies basically on the corrosion process of its reinforced steel component, it signifies that rusting is the main cause of the effect (El-Reedy 2007). Rusting occurs due to the presence of four factors, namely the metal itself, varied levels of energy, electrolyte, and the connection of a metal substance. In the reinforced concrete, the rebar may exist in various locations with varied levels of energy. Concrete serves as electrolyte while the wire ties, chain supports or the rebar itself acts as the metallic connection.

Causes of Concrete Deterioration and its Consequences

Free-thaw deterioration as one of the causes of concrete deterioration occurs due to freezing of water in the concrete resulting in its expansion. Freezing of concrete’s water content contributes to the production of pressure in the capillaries and pores within the concrete (Lamond & Pielert 2006). Where this pressure finally ends up becoming more than the tensile strength of the concrete, it finally leads to its dilation and rupture of the cavities thus resulting in the process of its cracking, scaling and crumbling.

Apart from free-thaw action, another cause of concrete deterioration is the chemical effects or attacks. For instance, in some cases, the presence of chemical environments may lead to the deterioration of the quality of concrete (Lamond & Pielert 2006). On a related note, some aggregates may end up reacting with alkali hydroxides found in the concrete material thereby leading to its expansion and cracking with time. In addition, the instance of abrasion or corrosion may result in the damage of the concrete surfaces thereby making the material not able to be resistive to wear brought by rubbing or friction. Following the wear out of the external part of the concrete, there is the exposure of both the fine and coarse aggregate components thus paving the way for the process of abrasion.

Fire as an element of concrete deterioration usually leads to the deterioration process of the substance through its effect of high temperatures that makes concrete lose its stiffness and strength (Lamond & Pielert 2006). On the other hand, a slight change in the volume of concrete due to moisture fluctuations and temperature may cause the cracking of the concrete material. The reason is that concrete is usually resistant to volume changes such as contraction since it causes cracking, especially where tensile stresses tend to develop in excess of the capacity of concrete’s tensile strength itself (Lamond & Pielert 2006). Similarly, incidences of overloading of concrete such as earthquake damages may lead to the deterioration of concrete structures. Other causes of concrete deterioration may occur due to instances of surface defects that emerge on the finished or formed concrete. Most of these defects may be avoidable though in some cases, their avoidance may not be completely achieved.

Hairline crack

Hairline crack is the type of crack that results due to stress relief. In most of the occasions, its formation occurs when tensile stress develops in the concrete and consequently exceeds the capability of the concrete material to manage or be resistant to such stresses (Gucunski, Imani & Romero 2013). In other cases, hairline cracks are formed within the countertops due to the instance of flexing tightened faucet, or settled household.

Multiple Cracks “1.5 mm” and Multiple Cracks “3 mm”

Generally, the representation of the OB steel involves the use of various compliance gauges. Compliance gauge itself is the relationship that exists between the back strain and the specimen aspect ratio for the compact (Gucunski, Imani & Romero 2013). In case the placement is approximately 3 mm, it is the multiple cracks “3 mm,” while if it is approximately “1 mm” or equivalent to it, it is the multiple cracks “1.5 mm”.

Minor Spalling and Severe Spalling

Minor spalling requires the application of bonding slurry that has a ratio of 1:1 cement/sand mix with the inclusion of an agent of bonding (Gucunski, Imani & Romero 2013). In such cases, the layer should not be more than 3mm in thickness, and surface must be clean and saturated before the application of repair mortar. Severe spalling, on the other hand, may require the replacement of the wall section.