Posted on September 06, 2018
In every construction project, it is incumbent upon all stakeholders to evaluate it from a lifecycle perspective. A thorough lifecycle analysis reveals the many benefits of concrete.
In an era of increased environmental awareness, such considerations are even more important. In general, the environmental impact of a given building or pavement project decreases when materials last longer. Projects with shorter lifespans tend to generate waste quicker and consume more resources.
How Does Concrete Deliver Savings Over Time?
Although budget constraints may focus developers and designers on upfront costs, it is important to consider the costs that accrue throughout the project's entire lifecycle. For both buildings and pavement, lifecycle costs begin with materials acquisition and conclude with end-of-life processes like demolition.
Both Life Cycle Cost Analysis (LCCA) and Life Cycle Cost Assessment (LCA) are vitally important. The LCCA process evaluates economic impacts, while the LCA process focuses on the environment. Together, these analytical methodologies enable decision-makers to better understand a project's true costs over time.
In this video, Dr. Jeremy Gregory, CSHub's Executive Director, highlights the lower lifecycle costs, reduced carbon emissions and long-term performance associated with concrete construction. Another video offers a more in-depth look at the advantages of ICF construction. It is important to consider the true lifespan of the shell of an ICF building, which can approach an even exceed a full century.
Five Key Elements To Maximizing Your Budget With Concrete
There are five important areas where concrete typically outperforms wood-frame construction.
1. Lifecycle savings
Numerous lifecycle advantages, both economic and environmental, accrue when durable concrete is used rather than softwood lumber. Some are related to longer estimated life spans for concrete building shells. Others relate to concrete's endurance in natural disasters.
In terms of hazard-resistance, concrete's lead over wood is notable. CSHub researchers have developed a metric, the Break Even Mitigation Percent (BEMP) to help designers determine how much to invest in hazard mitigation. ICFs often enjoy an edge in BEMP analyses.
2. Energy efficiency
Various studies underscore the energy-efficiency of ICF construction. For example, Second and Delaware is an ultra-green, 275-unit project overlooking the Missouri River in Kansas City. Energy use is projected to be 80 percent less than with conventional construction. During its full lifecycle, Second and Delaware will save approximately 480,000 tons of greenhouse gas emissions. Lifecycle costs will be 19 percent lower than wood frame construction, and operating costs will be slashed by 90 percent.
The new Shikellamy Middle School in Sunbury also features ICF construction. Natural gas heating costs declined from $0.49/sq-ft in the old buildings to just $0.15/sq-ft in the new one. The insulating capacity of the ICF walls also reduced the size of the boilers required.
3. Environmental impact
The exceptional thermal mass of concrete is one of the reasons ICFs generate annual energy savings of 5-8 percent compared to softwood lumber.
Over its entire life cycle, a typical wood-frame building generates 3-5 percent greater greenhouse gas emissions than an ICF building. A key reason is the continuous insulation ICFs deliver. Due to thermal bridging, wood framing requires extra insulation steps to meet today's stringent building codes.
In one LCA study, conducted in accordance with ISO 14044, both ICF and wood-frame construction of a two-story, 2,450 sqft home were modeled in five cities. Using five different methods to analyze impact data, researchers concluded that more than 95 percent of adverse environmental impacts were from energy production. The final report stated, "The ICF house performs better than the wood frame house because of the additional added R-value of the insulation and the thermal mass of the concrete."
4. Maintenance-free designs
Low-maintenance concrete designs are also innovative, dynamic and aesthetically pleasing. All those involved, from builders and contractors to landlords and building supervisors, benefit from concrete construction that requires minimal maintenance year after year. Wood-frame buildings often require work like painting/staining, spot repairs and early replacement, particularly when natural and other disasters strike.
5. Raw material resourcing
The raw materials in ready-mixed concrete are usually obtained locally. By contrast, softwood lumber, whether domestic or imported, is subject to supply and price fluctuations. Also, softwood lumber must often be transported across great distances, adding to fuel costs and carbon emissions.
Concrete vs. Alternative Materials
Across a wide range of applications, concrete's strength allows you to use less material to achieve the same standards. Concrete construction competes well with wood-frame buildings and asphalt roadways.
Concrete delivers unparalleled freedom of design compared to wood-frame construction. Concrete structures are typically safer when floods, extreme winds and other natural disasters strike. In many building applications, its sound dampening capacity is another important advantage.
Compared to other materials, insulated concrete forms (ICFs) go up quickly, use less labor, save more energy and dampen sound better. Specifically, ICF walls offer a superior sound transmission class (STC) rating of 55 vs 38 for a wood-framed wall. ICFs minimize the transmission of loud voices and other sounds.
One study evaluated the "global warming potential" of commercial and multi-family ICF and wood-frame structures in Chicago, a city with a climate comparable to communities in Pennsylvania. ICF construction performed better in all the examples provided.
Those that opt for ICFs can further reduce environmental impact by 1) increasing fly ash, and 2) increasing the thickness of the insulating panels surrounding the poured concrete core.
MIT's CSHub asserts that the future expenses of a paving project can be more than half the total life-cycle cost. By embracing CSHub models, Colorado improved 20-year cost estimates of paving projects by 32 percent.
LCAs factor in variables frequently overlooked in the past. For example, analysis of pavement-vehicle interaction promotes the use of stiffer, smoother concrete pavements that reduce fuel consumption and carbon emissions.
The Pennsylvania Concrete and Aggregates Association (PACA) reports on research and developments impacting the industry. Our mission includes educating Pennsylvanians about the value of concrete construction. For more information, please contact us.