Concrete is one of the world’s second-most widely consumed materials and an indispensable element of modern construction due to its flexibility, availability and long-term performance.
Curing is essential to concrete’s success. This involves keeping it damp or moist so it remains hydrated, maintaining strength and achieving maximum performance.
Strength
Concrete slabs Melbourne can be an incredibly strong material when properly cured; when improperly cured, however, its chemical process of cement hydration does not fully complete and its strength diminishes significantly. When improperly cured concrete sets hard and remains hard-packed for too long after curing has begun. When this happens, problems like grazing, surface disintegration and scaling occur that lead to structural damage which are difficult to correct.
Three practical curing techniques that can be implemented early in the hardening period include maintaining mixing water early, limiting moisture loss from surfaces, and providing heat or additional moisture to accelerate strength gain. These strategies can be utilized for large areas or structures with wide surface area ratios relative to depth such as chimneys, roads, canals and bridges.
Rebound hammer and penetration resistance tests are often used to verify that concrete has set, yet these methods require damaging the concrete, making their results inaccurate compared to laboratory-based core analysis testing from well-cured sections of concrete. To obtain accurate test data it is highly recommended that contractors employ a construction management solution like Pro Crew Schedule for monitoring curing progress throughout a project.
Durability
Concrete needs the ideal moisture content (OMC) in order to complete its cement hydration process and prevent shrinkage cracks, so curing must occur to reach this ideal moisture level and avoid shrinkage cracks. Curing helps reduce shrinkage, permeability, improve strength, durability, water tightness, abrasion resistance and watertightness while simultaneously decreasing shrinkage, permeability and improving water tightness and strength.
The hydration reaction can be affected by both concrete and air temperatures. When too cold, its reaction slows significantly while when too hot it produces significant temperature differentials within the concrete that could lead to cracking and cause it to set abnormally quickly.
Contractors use various techniques to maintain the optimal moisture levels during curing of concrete, such as spraying it down periodically with water to offset evaporation or using blankets and polyethylene sheeting as insulation materials. When curing flat surfaces such as floors & pavements, contractors may employ “ponding”, an approach in which clay or sand ponds are created above the concrete to keep its surface saturated with moisture.
Watertightness
Concrete loses moisture during its early stages, and to maintain strength it is essential that this moisture remains until the chemical reaction that sets the concrete begins. Otherwise, cracks can form and crumble further weakening its structural integrity. Proper curing helps prevent this by grazing dusting surface disintegration as well as shrinkage reduction as well as providing better resistance against freezing/thawing cycles.
Curing concrete can be accomplished in several ways. When air temperatures remain above freezing, regularly sprinkling concrete with water can help ensure its curing process goes smoothly. Ponding can also be effective at flat surfaces where they have sufficient surface area; however, for best results the temperature of water used must not be more than 20 degrees cooler than its respective concrete temperature and its perimeter dike must be secure against leaks.
Burlap, sand or canvas coverings that do not contain iron-staining pollutants may be used to wet the concrete before its initial setting time has occurred – this method is known as immersion. Immersion works best on larger areas.
Aesthetics
Many concrete projects are highly aesthetic in nature. For instance, many clients request colored concrete for projects like custom hand cast fire features. This type of concrete must be properly cured in order to achieve both an appealing final look and long-term performance.
Curing is the process by which water reacts with cement particles to form the “hydration of cement,” an essential process responsible for giving concrete its strength. Proper curing conditions help expedite this hydration and ensure that your concrete will be ready for finishing when its time has come.
Although curing concrete might seem obvious, its importance can often be neglected or taken for granted. Failing to adhere to sound curing practices could result in reduced strength, poor durability and structural damage in some instances.
