One of the factors that cause deterioration in civil engineering structures and deformation of building materials is lack of thermal stability which is prompted by thermal agents such as temperature changes. Temperature changes are effects of fire outbreak and result in expansions or contractions.
Fire is one of the hazards that a structure is likely to experience during its life cycle. It is a rapid oxidation process accompanied by the evolution of heat, light, frame and the emission of sound. The three elements required for fire to ravage a structure include fuel, oxygen and heat. It generates extreme temperature that affects the structural integrity of the building, causing reduction in material strength. Apart from the negative effects fire has on buildings and structures, it also has dire consequences on the safety of lives.
Heat Transfer During Fire Outbreak
The heat generated during fire outbreak can occur in about one to three dimensions. In almost all real situations, heat flow occurs in three dimensions but, from a practical point of view, it is often acceptable to simplify considerations to only one-dimensional, or series, heat flow. Heat transfer occurs by three primary mechanisms, acting alone or in some combination:
- convection, and
Conduction: It is the flow of heat through a material by direct molecular contact. This contact occurs within a material or through two materials in contact. It is the most important heat transport mode for solids; it is sometimes important for liquids, and it is occasionally important for gases.
Convection: The transfer of heat by the movement or flow of molecules (liquid or gas) with a change in their heat content. This is an important heat transfer mode between fluids and solids, or within fluids.
Radiation: This is the transfer of heat by electromagnetic waves through a gas or vacuum. Heat transfer by this mode requires a line of sight connection between the surfaces involved. All objects above absolute zero radiate heat energy; it is the net radiative heat transfer that is the heat transfer of interest. Radiation is mostly of importance for heat transfer between solids and within highly porous solids, but radiation between high-temperature gases is occasionally of practical importance.
Effects of Fire on Concrete Structures
Though concrete has a relatively poor thermal conductivity which causes slow rate of heat transfer, when a fire exposes concrete to high heat, extensive damage can occur because of the temperature shock to the material.
Actually, like most any other material, concrete expands as it’s heated. When extreme heat is applied, the outer layers will expand much more quickly than the inner sections. This “differential expansion” is not easily absorbed by the concrete material, which can cause the layers to separate and eventually break away. The same effect can occur in reverse when a fire is doused by hose streams or automatic sprinkler systems. In this case, as the hot concrete cools suddenly, the outer layer may shrink at a different rate and break away.
Additionally, if extreme heat penetrates concrete enough to weaken the steel reinforcement components within the concrete, the structural integrity of the entire structure could be adversely affected.
The effects of heat during fire outbreak lead to severe spalling, formation of obvious cracks, exposed structural steel, or deflection of the structure, and are capable of causing serious injuries or death to the people around.
The Need for TMT Iron Rods with Thermal Stability
Any TMT iron rod that has thermal stability can help reduce the effects of fire on the building. Thermal stability in TMT iron rods gives buildings and structures ability to withstand fire hazards, enables them to resist loss of structural strength at higher temperature, and withstand all types of moist conditions which can cause deterioration in the buildings.
By resisting fire hazards, and withstanding extreme temperature, TMT iron rods ensure the safety of buildings, enhancing their flexibility, structural strength and lifespan. Building with TMT iron rod will limit the potential for death and injury among the occupants of the buildings and provides protecting contents that make the building reparable and continues to function after a fire incident.