By SETH ULMERConcrete Construction
Driving efficiency with monolithic pours
Throughout history, new processes have come along to improve how people achieve end results. Innovations, even those that eliminate just one step, often lead to dramatic increases in productivity and efficiency.
Developing film is a good example. When digital cameras entered the market, they cut out the step of going to the store to develop a roll of film, accelerating the process of viewing family photos.
When it comes to concrete, monolithic pours are one process that contractors can use to drive efficiency. Monolithic pours streamline concrete work by pouring curb and gutter simultaneously with flatwork, instead of completing these pours one at a time. If completed with the right equipment and considerations, contractors can reap the benefits without sacrificing quality.
A traditional pour most often requires curb and gutter work to be poured, finished and cured to outline the pavement area. Then, the crew returns at another time to pour and complete the flatwork. A monolithic pour, or an all-in-one pour, improves efficiency by completing curb and gutter at the same time as flatwork, saving a considerable amount of time.
Driven to continually seek new ways to keep up with ever-growing demand, more contractors are seeing the benefits of monolithic pours, especially for parking lots and streets. Contractors who streamline the most time-consuming aspects, such as hand-shaping curb and gutter, experience the most significant spike in efficiency and often double production. Just as the digital camera created a more productive photo development process, monolithic pours can drive up efficiency for contractors.
PUSHING THE PACE
As contractors look for ways to maximize efficiency, many turn to laser screeds to boost flatwork capabilities. Their ever-wider adoption in the market has significantly sped up the process of screeding large areas of flatwork. But contractors lose the efficiency gained with a laser screed if the curbing work falls behind during a monolithic pour.
Crews that are responsible to shape and finish the curb by hand typically operate at a slower pace than a laser screed. This can slow the whole operation as they wait for the curb to be completed before moving to the next section. While slipform pavers can be an option, their size may complicate a busy jobsite and they may not be ideal for relatively complex areas of curbing associated with monolithic pours.
Walk-behind curbing machines are able to maintain the production pace of laser screeds while eliminating the physical labour and need for large machinery for curbs. These machines consist of a handle attached to a metal drum that is connected to a hydraulic power source.
The single-operator machines reduce the manual labour needed when shaping the curb and gutter while producing a consistent result, even for operators with minimal experience. While these machines were originally developed for completing curb and gutter work on traditional pours, most can be modified to adapt them for use during monolithic pours.
Newer entries to this class of equipment incorporate battery power and a design specifically created for monolithic pours. These machines combine the benefits of traditional walk-behind curbing equipment with lightweight portability to quickly move throughout the jobsite.
A concrete contractor hired to install a large parking lot for a private company used a laser screed due to the sheer size of the project. Working during the night to limit traffic interference, they were able to pour about 2,000 yards of pavement per night. The operation was limited by the finite amount of curb the crew could shape by hand, however: only 300 to 400 feet per night. When the contractor invested in a battery-powered walk-behind curbing machine, the crew doubled productivity, shaping closer to 700 linear feet per shift and achieving their target efficiency.
TAKING TO THE STREET
Laser screeds and walk-behind curbing machines are ideal for projects like parking lots — jobs with large amounts of flatwork and multiple areas of curb. However, a single machine that can shape curb and gutter simultaneously with flatwork is more ideal for certain monolithic pour applications like street construction or replacement.
Traditionally, large slipform machines have been the most efficient solution if the project matches the machine design parameters and has enough volume to justify their operation and overhead costs, but new equipment offerings are expanding the options for these jobs.
Some manufacturers offer custom drum options for hydraulic screeds. These drums, typically up to 16 feet long, are designed to match a specific shape, like half of a street, including the curb and gutter. Custom drums replace the pipe on a hydraulic roller screed and use a spinning motion to shape the concrete.
This monolithic pour method is ideal for streets due to the long stretches of pavement that are the same shape, and it can be convenient for replacing existing streets because it allows one lane of traffic to remain open.
In the past, this was only possible with large, slipform pavers or through manual labour, but a custom drum with a hydraulic screed now provides an additional method to complete the work.
DRIVING CONSISTENCY AND QUALITY
A common misconception is that monolithic pours produce low-quality curb work. This may be true if the crew has little experience in curb and gutter work and is hand shaping the curb while being primarily focused on flatwork, which is the larger portion of the job. But properly equipped, a key advantage to a monolithic pour is increased all-around quality — if contractors use the proper equipment.
Replacing manual curb work with a mechanized system makes it easy to achieve consistent, spec-matching results, even with an inexperienced crew. The equipment is user friendly and enables contractors to accomplish more with less labour, a key advantage in a difficult employment environment.
FACTORING IN THE WEATHER
A key consideration when determining whether a monolithic pour is the right solution is the weather. Monolithic pours really shine in tough weather conditions. As seasoned concrete workers know, the weather dictates when and how efficiently they can pour. Dealing with a small pour window becomes less of an issue with a smaller number of pours.
With the right equipment, monolithic pours can double or even triple production and help crews maximize the work they can complete before that window closes.
Despite all the advantages, there are some cases where a monolithic pour is not the best solution. These situations will come into play in colder climates.
If a job uses asphalt for the pavement, the concrete curb and gutter must be poured separately. Additionally, the monolithic pour method is not ideal if the curb and gutter or flatwork may need to be replaced separately. In some regions, freeze and thaw cycles can lead to a shorter life for the curb and gutter than the pavement.
BEYOND THE MONOLITH
Contractors can maximize their investment in concrete equipment by purchasing machines that increase productivity for a variety of applications. Beyond custom drums for monolithic pours, hydraulic screeds also pair with standard pipes to screed flatwork for jobs such as streets and sidewalks.
Walk-behind curbing machines have multiple drum options and can also complete curb and gutter for traditional pours. Additionally, battery-powered walk-behind curbing machines effectively complete patch and repair work and complement slipform machines to complete corners and tight radii.
The demands of the construction industry are shifting rapidly. There is a high demand for work, and contractors can capitalize on these opportunities by finding innovative solutions that improve their processes and increase their capacity. Monolithic pours are not the answer for every concrete project, but with the right equipment and the right application, a monolithic pour may be what drives an operation to peak efficiency.
Seth Ulmer is the sales manager at Curb Roller Manufacturing, a leading manufacturer of shaped concrete roller screeds.