Concrete Considerations

A maintenance strategy based on prevention, inspection and detection keeps facilities operating safely and cost-effectively

By Mark Sitar  

Challenged to provide more and better service with streamlined resources, health care organizations are finding that economic belt-tightening has become a way of life. Couple this issue with the need to integrate durable building materials, and it is little wonder that concrete is a solution for many organizations, especially in areas of facilities that require immense strength, fire-resistance, and even blast-resistance.

For all its seeming permanence, however, concrete comes under constant attack from both natural and man-made forces. The relative rate of degradation resulting from these assaults depends on a variety of factors. With a deeper understanding of strategies to strengthen and repair concrete, maintenance and engineering managers can reduce labor and material costs related to maintenance and produce long-term success.

Invisible Problems

In coming years, health care facilities will spend millions of dollars on facility infrastructure projects and repairs that generate little to no revenue. While integrating new equipment for a new treatment option or a wing expansion that increases the number of beds might add to the bottom line, maintenance and repair of concrete structures produces no revenue and, as a result, is too often overlooked.

This approach is dangerous because concrete requires preventive maintenance in order to last. Although the process of deterioration often takes years to show itself, the damage is exponential and develops into more expensive and extensive repairs.

The damage is especially prevalent in areas such as boiler rooms because these spaces are designed to be tightly sealed and out of the sight of patients. Also, the steam and humidity consistently present in these rooms have nowhere to go. The result is deterioration of the reinforced concrete.

Another challenge resulting from the location and design of boiler rooms is the fact that they are set in areas that often are difficult to access and are congested with mechanical equipment, further complicating the repair process.

Given these challenges, deterioration is likely to result, typically when moisture and chemicals penetrate the concrete. Corrosion can go undetected until the concrete starts to crack and spall. In cases where equipment is located on the concrete slab above the boiler room, a coating or lining system commonly is used to prevent chemicals and water from penetrating from above.

Identifying Culprits

Besides the institutional mistakes contributing to concrete degradation, a range of natural and man-made factors also come into play. Although concrete found in most boiler room walls typically is protected inside a structure and not affected by freeze-thaw cycles, man-made forces can cause degradation.

These sources include deficiencies and a failure to properly inspect and maintain the concrete. Also, workers might spill chemicals or some other mildly aggressive agents onto concrete but not properly clean them up, which could cause degradation or exacerbate an existing problem.

Foremost among the causes of concrete degradation is internal damage caused by the corrosion of embedded reinforcing steel. This scenario is especially prevalent in boiler rooms in which steam and condensation trapped by waterproof systems accelerates the corrosion. Besides leading to deterioration of the steel itself, corrosion also affects the concrete surrounding it, resulting in cracking, spalling and delamination.

Most concrete in structures is steel-reinforced and represents a widespread problem that can cause concrete to spall and eventually fall, possibly damaging vital equipment or piping. Such a scenario also poses a threat to any nearby hospital personnel.

Unfortunately, signs of concrete deterioration typically do not indicate a problem’s true depth, complexity or severity. From day one, concrete comes under attack from environmental factors, and its deterioration is insidious and continuous.

The first small crack in concrete’s protective lining invites intrusion by moisture or corrosive agents. Eventually and inevitably, the outward symptoms of scaling, cracking and spalling appear.

Without exception, degradation exists in most concrete. The only variables are the way and the time the problems will manifest themselves and whether they have reached the stage at which they jeopardize ongoing operations and affect operations and profitability.

Inspection Issues

The underlying danger in making repairs is that they might become part of a costly cycle, rather than producing a solution. So it is important that managers have technicians inspect concrete areas to determine the root cause of the degradation.

A visual inspection should be the first step in any maintenance program. If an inspection shows no sign of deterioration, technicians do not need to take any other actions, and managers can schedule another inspection for the following year.

But if the inspection reveals signs of deterioration — cracking, rust staining, or effloresce — inspectors should perform more tests, both non-destructive and destructive. These tests include but are not limited to: acoustical impact, or hammer sounding; chloride concentration; carbonation; and petrographic analysis of extracted cores.

The results of these tests will determine the level of deterioration and help managers to develop or update, and then implement a proper repair strategy.

Maintenance decisions

Once a manager decides to undertake concrete repairs, the next step is examining repair strategies and selecting the best course of action. Today’s technologies have advanced far beyond the simple concrete patch. Technicians can use a range of solutions to efficiently and cost-effectively repair concrete.

A basic understanding of these maintenance options — surface repair, protection, stabilization, strengthening and waterproofing — will allow managers to select the best program for a facility. A concrete repair specialist can help determine both the underlying cause of the problem and the optimal solution.

With so many possible strategies, a typical repair strategy might implement solutions from more than one category to achieve the best results. Managers can best determine the most appropriate repair by involving all parties associated with the repair, including the engineer, concrete repair specialist, and facility director.

In doing so, managers will need to consider such factors as ongoing hospital operations and service life. Deciding on the most appropriate concrete repair materials is often an exercise in compromise. Even the most seasoned repair technicians find it difficult to select one product that meets all of a project’s needs.

At a minimum, the chosen materials should fill the repair cavity completely, avoid shrinking during the curing cycle, and behave similarly to the existing substrate when subjected to loads, temperature fluctuations and changes in moisture content.

Putting Lessons into Practice

Maintenance budgets typically are better funded for repairs of equipment and systems. By comparison, structural repair budgets, tend to be a much lower priority — that is, until a structural problem deteriorates to the point where it jeopardizes facility operations.

Effective concrete repair solutions include a commitment to learning from past experiences and addressing problems with the goal of ensuring the long-term integrity and service life of a facility’s infrastructure.

Educating front-line technicians concerning concrete material basics, deterioration mechanisms, repair strategies and construction techniques will enable repair teams to make better decisions on concrete repair strategies and prevent more costly repairs.

Failure to take preventive maintenance steps or properly address signs of concrete deterioration can have a dramatic impact on the operations of a facility. Degrading concrete is a lurking threat that managers cannot afford to ignore.

Mark Sitar is branch manager/industrial division operations manager with Structural Preservation Systems Inc. — www.structural.net — a leading provider of structural repair and protection and strengthening services.

Diagnosing Problems, Specifying Remedies

Specialists in the field of concrete repair point to a range of possible shortcomings that can contribute to the urgent need for repairs to some concrete. Among the problems are these:

  • inappropriate selection of structural systems
  • inadequate design details
  • lack of clear direction of the design implementation during construction
  • lack of consistent quality control during construction
  • lack of standardized educational tools, such as guidelines for repair of concrete problems
  • change of a structure’s use from the original design intent.

Keeping those factors in mind can be useful to managers in avoiding the same mistakes for future concrete construction and repair strategies.

Managers should consider each of the following questions in specifying repair materials:

  • What are the performance requirements of the area to be repaired?
  • What are its service and exposure conditions?
  • What loads will the area be required to carry?
  • What will the operating conditions be during concrete placement and cure?
  • Has the original cause of the concrete deterioration been addressed?
  • What concrete placement techniques has the organization selected?
  • What characteristics are required for concrete placement?
  • What properties are necessary to meet these conditions and requirements?
  • What materials or systems will provide the required properties?

By understanding the problem areas and exploring the repair considerations, managers will find themselves in a better position to make a cost-effective decision on selecting a concrete repair strategy.

— Mark Sitar

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  posted on 10/1/2005   Article Use Policy

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