Anderson Awarded for his Contributions to the Industry
Dennis “Hap” Anderson was awarded the Robert D. Sawyer Distinguished Service Award at the CFA annual awards luncheon Saturday, August 9, 2003, at the Kingston Plantation Resort in Myrtle Beach, SC.
Hap, president of Anderson Construction Inc, is recognized for his contributions to the industry over the past four decades. A founding member of the Concrete Foundations Association, Hap Anderson has been an active member and supporter since 1975. Hap attended the first poured wall contractor conference in Chicago, IL. He helped define what a poured wall contractor was, outline the reasons a poured wall association was necessary, chose the original name for the association (Poured Concrete Wall Contractors of America), and recruit members. Hap served as president of the Association in 1978-79, and also volunteered his time on the board. “Hap’s leadership qualities include inner strength, resolve, focus, confidence and integrity,” states David Isaacson of Isaacson Construction Inc., who presented the award. “These things he passes on to others not knowing the impact they have on all who come into contact with him.”
The Robert D. Sawyer Award is named on behalf of Bob Sawyer, the first Executive Director of the CFA. The award is presented to a CFA member whose contributions to the concrete foundation industry merit recognition. It honors individuals who selflessly give their time and resources to serve the industry, as Bob Sawyer did for the CFA through its formative years.
“Older members know how important this award is.” Isaacson states, “[This year’s recipient] is a man that I hold in the highest esteem. He has been a mentor to many. I am thankful to know him and honored to call him my friend.”
Anderson Construction Inc., founded in 1963, currently provides excavating concrete walls, flatwork, and waterproofing services for the Springfield, MO area. Hap is presently semiretired with three employees in his company.
Other presentations at the luncheon include recognition of long-standing CFA members and acceptance of the coveted Basement of the Year award plaque by Gary and Dan Bromley of ABI Corporation, Lee’s Summit, MO. The Basement of the Year is determined annually by member votes at the CFA booth during the World of Concrete.
BEP Big Panels – Saving Time and Manpower for Martinson Construction
“They pour nice walls – straight and square,” said Dave Martinson of Martinson Construction in Waterloo, Iowa of B.E.P. Forming System Inc.’s new Big Panels. They also allow Martinson to do work in less time with fewer workers.
Martinson Construction used the Big iPanels and power ties to construct a data center for Team Technologies, an organization that provides system and network integration services and internet solutions in the upper Midwest.
There were a total of three buildings constructed for Team technologies in Cedar Falls Iowa. A nearby building, constructed by Martinson Construction and similar in structure to the Team Technologies data center, averaged 14-foot walls and was completed by 12-15 workers in approximately eight weeks using the traditional aluminum forms. The data center was constructed by seven workers, using the larger forms, and was on schedule for completion two weeks earlier than the nearby building.
The B.E.P. panels are different from the traditional forming systems in that they are completely crane-set with the use of a lightweight crane, all-terrain forklift, bobcat crane attachment or track-style backhoe. The crane-set system is highly adaptable to below-and-above-grade, cast-in-place residential and commercial concrete projects, and features a one-man lifting hook device. Lightweight but strong, these panels hook to any conventional aluminum system, steel frame or locking plywood system. Heavy-rail systems with corner guests are high-penetration welded to standard .125 inch thick face-sheet or optional heavy-gauge .160 inch face-sheet to create the strongest big panel in the industry engineered to handle up to 1,450 lbs. per sq. ft. loads, based on ACI pour ratings.
The forms use power ties, similar to large bolts, rather than traditional taper ties to secure the forms together, which facilitate faster set-up and stripping time. There are no loose parts and the tie spaces itself with unique bearing spacer plate to pour different widths of wall. The power ties are placed on the interior so that no holes are seen on the exterior. The holes are then filled. Ties are available in nominal and full width dimension and support up to 40,000 lbs SWL (Safe Working Level).
For this project Martinson constructed 60-70 ft walls using 9′ x 24′ Big Panels. To move the forms, Martinson’s crew moved the panel by taking it down and rotating it. Martinson pointed out the section is by no means a maximum. “If you had a good crane, you could move more forms at once,” he stated.
Ideally, every other day was scheduled to pour with the remaining days to set-up forms. Martinson finds commercial work, such as this data center, is often more complicated than residential because every project is different. He states, “Everything has been a challenge all the way around. There wasn’t one panel that didn’t have a lot of stuff go into it.”
For commercial building, workers are often on the sight longer. However, B.E.P. Forming System Inc.’s new forms saved a lot of time and manpower that would otherwise be needed to complete this project. Martinson was able to cut his manpower in half and shave of a few weeks for completion.
For more information about B.E.P. Forming Systems or the Big Panel System, visit www.bepformingsystems.com or call 1-866-BEP-FORM (1-866-237-3676). B.E.P. Forming Systems is a family-owned aluminum forming company committed to providing residential and commercial contractors with technological innovations in form design and accessories. The company’s goal is to help contractors maximize profits by saving time and reducing labor and equipment costs.
Martinson Construction, the largest concrete contractor in the Waterloo/Cedar Falls area, complete 275 to 300 foundations per year in addition to their commercial business.
Association Marketing and Branding Efforts Focus Largely on Public Relations
For the past two years, the CFA has put tremendous focus on public relations efforts. Lacking the vast resources and dollars needed to embark on a national advertising campaign, your Association Board opted to build the awareness of cast-in-place concrete foundations through the PR vehicle and take advantage of the third-party credibility achieved with this marketing tactic. CFA Initiatives have resulted in feature articles ranging from concrete cracking and the Basement of the Year competition to safe basement space and codes; a partnership with Concrete Homes magazine for a year-long series on the basics of foundation construction; as well as a variety of press releases and online postings. We believe the efforts have been successful in building a solid awareness of the benefits of poured wall construction, yet there is still much to do. Our 2004 program includes the completion of the Concrete Home series, which will increase the expert position of CFA, as well as educate homeowners on the benefits of cast-in-place foundations.
A PR program hinges largely on membership participation, and since it also serves to benefit you, we wanted to take the time to explain our goals and objectives. Having managed the PR effort or CFA for the last two years, I would like to share answers to some of the most common questions we receive regarding the awareness campaign.
WHAT IS PUBLIC RELATIONS
Public relations, or PR, is the formal way in which organizations communicate with their publics. It is planned or managed communication – a means to communicate, influence and sometimes even sell. The medium provides the necessary third-party credibility you cannot achieve with advertising and is a cost-effective means to build a brand. However, it should be noted that public relations requires a consistent and concerted effort – it is not as simple as sending one release. True public relations success is achieved by developing a program that carefully delivers a key message to target audiences.
WANT TO SEE YOUR PROJECTS IN PICTURES?
A picture really does tell a thousand words, and in case of public relations, good photography can make or break securing a story. With ever-changing technology and a variety of new products, the CFA is always in need of good job-site photographs. The advent and subsequent explosion of digital photography had a large impact on our photo archives. Obviously, digital technology provides for quick and easy manipulation and development of photographs for website and email purposes. However, most of these images are not suitable for print publications since most magazines require digital photos to be at least 300 dpi (dots per inc) and 4 x 6 in size – usually in TIF format. For cover photographs, a slide, transparency or 8.5 x 11 inch photograph is necessary. With only small digital files to choose from in our archives, the CFA is losing valuable opportunities in the media. For example, we lost an opportunity with Concrete Construction magazine early this year because high-resolution images were not available for the CFA project of interest to the editor. The lesson learned is to make sure your digital camera is set to take high resolution photographs before snapping a shot or simply use a 35mm camera so photos can be scanned at the proper resolution. If you have photos you are willing to share, please send them to CFA today. Your company will benefit from exposure since the photo caption and cutline (caption) highlights your company and project.
HOW CAN YOU BENEFIT FROM THE CFA PR PROGRAM?
In addition to building awareness of cast in place foundations – a phenomena from which we all benefit – CFA’s PR program is a resource for you and helpful in your marketing efforts. Published articles and press releases are posted on the CFA website and many are available in pdf format for you to download and share with prospective clients or other team members. Include the articles in your proposals, send them as a mailing to clients, or even repackage them as a column in your local business publication. If you cannot find an article on a particular topic, let us know. Chances are we have the piece you need, or it is something we could create for all members to use.
Further, CFA needs a list of technical experts to review articles, create white papers for the more technically-oriented publications or serve as interviews. If you have expertise and can spare time for this worth endeavor, please contact CFA today. Also, active involvement in the Association prompts us to call you next time we need an expert. Explore opportunities to serve on committees that interest you.
HOW DO WE KNOW IF WE ARE SUCCESSFUL?
Without a goal, how will you measure success? There are a variety of methods to measure the effectiveness of PR efforts – ranging from comparing space receive with the cost of buying equal advertising space to expensive market research of those reading target publications. CFA measures its results by establishing goals in terms of key audiences we reach and topics covered. Your participation in our program – either as a participation in a feature article or distributing published articles throughout the marketplace, simply aids and helps us build a stronger program.
CAN YOU HELP?
If you have any suggestions or topics you want covered in the Concrete Homes column or ideas for future feature articles, please contact Wendy Ward at wward@constructivecommunication.com.
Concrete Above-Grade Wall Systems: What are Homebuilders Thinking?
A summary of the PCA market research’s The 2003 Homebuilder Report
The Portland Cement Association (PCA) Market Research surveyed homebuilders across the United States in 2003 to assess the awareness and use of concrete above-grade wall systems and competing systems, as well as to measure the attitudes and perceptions of homebuilders toward these systems. In addition, homebuilders’ perceptions of homeowners were measured. Homebuilders were asked what is important to homeowners, how much more homeowners would be willing to spend for benefits such as energy efficiency and noise reduction, and how much they thought homeowners would be willing to spend for a concrete home. The survey focused on ICF construction, but most of the conclusions can be applied to all forms of concrete homes.
The research was conducted to measure the effectiveness of promotions by tracking market share, promotional successes, and the attitudes and perceptions of decision-makers. The survey was a follow-up to a survey of homebuilders completed in 1997 and two follow-up surveys completed in 1999 and 2001. Powerful comparisons are made among the three surveys of homebuilders and with four surveys of homeowners conducted between 1995 and 2002.
The two above-grade wall construction discussed in the report were wood framing and steel studs. Wood framing construction is the tradition form, and is the main competitor for concrete homebuilding, but steel studs and structural insulated panels (SIPs) are also serious contenders for market share. Steel studs are a system similar to traditional wood framing using light-gauge formed steel. SIPs are a system that has a structural composite wall panel consisting of rigid insulation sandwiched between two sheets of plywood, oriented strandboard (OSB), or waferboard sheathing.
Concrete homebuilding includes a variety of traditional and innovative systems. The most heavily promoted of these are traditional concrete block, insulating concrete forms (ICFs), and poured concrete/removable forms (PC/RF). ICFs are a system in which two parallel sheets of polystyrene are filled with concrete and left in place, acting as the insulation for the wall. Other concrete systems including autoclaved aerated concrete (AAC) and precast concrete are also included in the analysis. AAC is a system of lightweight concrete blocks made with extremely fine aggregate and an expanding agent.
The survey was completed by 1,111 single-family detached homebuilders in the following states: Florida, Kansas, Louisiana, Minnesota, Nebraska, Ohio, Oregon, and Texas. The average homebuilder who completed the survey has been building homes for 22 years, has built 17 homes in the past year, sells homes priced between $200.00 and $350.00 and builds homes with 1,800 to 3,000 square-feet. The result showed a drop in concrete products’ share, from 10.3% in 2001 to 8.5% in 2003. Most of the concrete products’ share consists of concrete block which fell from 6.8% to 5.1%. ICFs’ share dropped slightly from 2.4% in 2001 to 2.0% in 2003.
The results also found that awareness of concrete homebuilding remained unchanged. Awareness of the systems appears to have leveled off in 2003 after experiencing dramatic increases between 1997 and 1999. In 2003, 96% of builders were aware of concrete block and 83% of builders were award of ICFs. Awareness of most of the systems did not vary significantly between 2001 and 2003.
Homebuilders’ perception about the construction systems showed that poured concrete/removable forms (PC/RF) were rated the highest for durability, insect resistance, indoor air quality, disaster resistance, and environmental safety, while ICFs were rated the highest for energy efficiency and noise reduction.
Wood was the only system that builders were very likely to use all three years the survey was given. Concrete block was rated at the neutral level, while the other systems were rated at the unlikely to use or very unlikely to use levels. Builders were more likely to use all of the systems in 2003 than in 2001.
The results found that the five most important characteristics were low initial cost, design flexibility, energy efficiency, durability, and construction time. In 2003, 39% of the builders were likely to build a concrete home with a comparable cost to wood, which remained steady with the 2001 rate of 40%. Unfortunately, the percent of builders who thought their homebuyers would be likely to build a concrete home if it cost 2% to 5% more than a wood home fell from 27% in 2001 to 18%. However, 90% of the builders thought homebuyers would be willing to spend at least 1% more for an ICF home and 16% thought homebuyers would be willing to spend at least 5% more.
Over 75% of homebuilders thought homebuyers would spend more for energy efficiency (98%). indoor air quality (98%), noise reduction (87%), disaster resistance (96%), and environmental safety (84%).
Future surveys include an update of the homeowner survey in 2004 and an update of the homebuilder survey in 2005.
The contents of this article consist of excerpts from The PCA’s The 2003 Homebuilder Report.
CFA Board Member Changes Her Name
CFA board member Amanda Herbert married Josh Morris on Saturday, May 24th, 2003, in Allegan, Michigan. The couple exchanged vows in the company of family and friends, including CFA members: Charles Engelken, Bill Esker, Terry Lavy, Greg Peacock, and Arie Van Wyk.
Congratulations Amanda Morris! Best wishes to you both!
CFA Website – Accessing and Working with Documents Online
Over the past couple of issues we have spent time together investigating the use of our member/non-member site access and dealing with the issues of membership maintenance and event registrations. This time around, I am taking you on an educational trip on the interaction with this site to view documents that we are providing to the membership. These documents include issues like The Business Owner, Concrete Facts – the CFA Newsletter, Board agendas, Board minutes and other electronic versions of our various brochures and informational offerings.
Documents that we make available to CFA members are placed on our server in a format known as PDF. This stands for Portable Document Format and is a universal file type created by Adobe to allow distribution of high-quality web documents across all platforms. To view these documents, the only requirement is that you have the software Adobe Reader installed on your computer. Nearly all computers will have this already as it comes with a wide variety of software packages to view help files and other important documents. In the event that you don’t have this software, it can be easily obtained for your computer from Adobe’s website at http://www.adobe.com/products/acrobat/readstep2.html.
The installation is quite quick and very easy should you need to get the program or be interested in updating to the latest.
With that straight, let’s go see some of the documents that you will be interested in looking at and some of the options you will have once you select a document for viewing. Once you have logged on to our site and you are now looking at the Welcome screen (something I hope each of you have been successful in doing, see fig. 1), you will need to select the menu item Publications and then View from the drop-down box (fig. 2).
CFA Newsletters – Concrete Facts
What do you do when you get in a situation and recall that the solution may have been in a newsletter a couple of years ago? How can you share an article written about your company with a new employee or a colleague but can’t remember where you placed it? How can you contact a company about a product that you saw featured in a newsletter a few months ago and realized that you haven’t been keeping your issues stored in your reference binder? These questions and many more can be asked over and over from the wealth of information that is presented in each issue of Concrete Facts. Luckily, we have designed a place where you can go to find articles that have been published in our newsletter and obtain a copy of the past issue.
When you have selected View from the Publications menu. You will see a table on the left of your screen that contains the CFA newsletters that are currently available for you to research. These newsletters are listed by their volume and issue number. The 2003 year is Volume number 10. You have two primary steps to take in your research process.
Step 1: Look through the Table of Contents of a Volume. You will see a button in each row for a given newsletter that says Table of Contents. Selecting this button will take you to a screen where you will be able to view the articles that were contained in that issue (fig. 3). Once you have finished looking through this issue’s contents, select the Close button to return to the publication tables.
Step 2: View the newsletter you are interested in. After you have located the newsletter you are interested in reading, you will select the View button. There may be a delay depending on the speed of your connection but once you have selected this button, your browser will begin building the newsletter in a separate window. Please remember that you may need to exercise some patience here as it takes a while to build a 32-page full color newsletter over a dial-up connection. When the document is finished building, your new window will look similar to the image in figure 4.
Your browser has been modified with additional features from Adobe Reader. The main buttons you will be using are Save, Print, Navigate and Zoom. You can find all of these in the pull-down menus but you should also know that each has buttons for quick use (figs. 5-8). Selecting Save will allow you to place a permanent copy of this issue on your computer for later use or reading when you get a full chance. The Navigate buttons are the best way to work through the document quickly. The left and right arrow buttons go page by page while the arrow buttons with a line take you immediately to the front or back page of the document. The Zoom buttons are important since you will not likely be looking at the entire page when it opens in your browser. If you want to see the full page as you scroll through the document, you can select the button that looks like a full page of paper inside a window. If you want the page to show up at or return to 100% zoom, you simply select the button that looks like a full page. Finally, if you want to read a given section and want to bring the width of the paper to fit your screen, you select the button where the paper width fits in the window but you don’t see the whole sheet. Again, all of this can be obtained from the menus at the top of your screen as well.
When you have finished looking through the document, simply exit this window as you would any normal website window with File and Close or selecting the “X” in the upper right corner. This will once again show the screen with the Issue tables. If you want to return to the Welcome screen you select the Close button, however if you want to leave completely, just continue closing like a normal window.
The Business Owner
Looking through issues of The Business Owner should be performed with the same steps describing the newsletters above. You will see this table on the right side of the publications screen. Again, table of contents are available for your viewing as well as the complete issues.
We are working continuously to add back issues periodically. If you have a specific article or issue in mind that you don’t see, please contact us and we will make that one a priority. We hope to have the entire history available by the end of this year.
Future Still Hopeful for Residential Construction Market
Construction Market Outlook of 2003 Second Quarter CONDENSED FROM FMI ANNUAL CONSTRUCTION OUTLOOK PUBLICATION
Construction, like many other industries, suffered a disappointing start to 2003. However, residential construction proved to play a crucial role in the construction industry as a whole. To sum up the second quarter, the boom in residential construction may have peaked, the commercial construction depression may have bottomed, and a public construction sector isn’t looking so predictable. The reason, in part, for the discouraging outlook of the second quarter was the uncertainty created from the war with Iraq. Many companies put a freeze on hiring to see what the outcome of the war was, which further hindered the already stagnant labor pool. The number of unemployed who continue to file for benefits after the initial claim rose to its highest level in three and a half months, according to the U.S. Department of Labor. Poor employment growth created a decrease in consumer confidence. The Conference Board’s consumer confidence index was the lowest it has been since October of 1993 when it reached a low of 60.5.
However, this gloomy employment and consumer confidence data may not win out in the long run. There are a few key facts to note about February’s weak economic numbers, which may make the future look a bit brighter. One factor in the low numbers is the calling up of the reservists. According to the U.S. Department of labor, approximately 150,000 reservists were called into active duty in February. These reservists called to active duty are not included on employer payrolls. If the worker is not replaced, then the data shows a decrease in the employer’s job count. A second factor is the severe weather the nation had this winter, which probably lead to a decline in hiring, as well as consumer purchasing in February. A third factor is that February has fewer days than any other month, which most likely affects the retail sales data. Finally, the fourth factor to note is that people seem more confident with the job market than the employment numbers suggest. According to job trends analyzed by Challenger, Gray & Christmas, Inc., this is shown through the number of workers reentering the job market, voluntarily leaving their jobs, or starting their own businesses. Bottom line – even though the numbers seem discouraging, the economy still seems to be on the mend.
In the construction industry, as well as in the U.S. economy has a whole, residential construction has been crucial for the past two years. This is largely due to the ample demand driven by underlying demographic and lifestyle preferences. However, while the long-term demand should remain steady, the short term drivers of demand – weather, conditions, consumer sentiment, and builder sentiment – were off in February.
The value of new residential construction raised 0.3% to a seasonally adjusted rate of $328.1 billion. New home sales fell 15% to a seasonally adjusted annual rate of 914,000 units in January. By February, the seasonally adjusted annual rate was 854,000 units, the slowest pace since August of 2000. The total months’ supply of new homes for sale increased from an average of four months to four and a half. Sales of existing U.S. homes fell 4.3% in February to a seasonally adjusted annual rate of 5.84 million units, according to the National Association of Realtors.
Residential builders cut back on new housing construction in February. Single-family housing authorizations were at a seasonally adjusted annual rate of 1,315,000, below the annual rate in January. Housing starts dropped 11% from January to February. February’s rate is also down 9.3% compared to the estimate rate in February 2002.
Whether February’s weak numbers is a one-time occurrence or not, the possibility of rising mortgage rates and a level of mortgage defaults determined unacceptable to bank regulators are two factors that can potentially hinder the residential construction market in the next 12 months. While mortgages are a hot item of the year, over 80% of their volume was refinancing. Interest in obtaining financing for a new home is growing less quickly.
With an increase interest in mortgages came an increase in the number of mortgage bankers, which has grown by 122,000, according to the U.S. Department of Labor. This inflation of bankers results in a lot of new mortgage bankers approving a lot of new mortgages – some which should not be approved. The repercussions of such occurrences may be increased foreclosures, which could result in tightened standards on home mortgages. Evidence of such repercussions appeared for the second consecutive edition of the Federal Reserve Board’s January 2003 senior loan officer opinion survey on bank lending practices. Not to mention, the number of banks tightening their standards edged up 1% from the 10% reported in the October survey. The evidence is minimal at this point, but tightened home mortgages standards could in the end greatly influence residential construction.
Mortgage rates are not the only thing to keep an eye on in the months ahead. According to the Department of Energy, the U.S. average retail price for regular gasoline increased 2.8 cents per gallon as of March 3rd to reach 168.6 cents per gallon, which is 54.2 cents per gallon higher than a year ago. Mortgage rates and oil prices relate from a long-term perspective. Residential mortgage rates are influenced by the rate of consumer price inflation (as measured by the rate of change in the consumer price index), and oil and other energy prices constitute a portion of the consumer price index (CPI). In January and February, the CPI rose 0.3% in January and 0.6% in February, with increases in oil, energy and food prices. If oil prices continue to increase, then inflation is passed down the supply chain to consumers, borrowing rates, including mortgages, could be affected. In turn, producers, wholesalers, and retailers will swallow the increased oil-driven producer inflation, and corporate profits will continue to suffer. This would be followed by continued poor employment and investment growth. It’s a nowin situation that nobody wants, and can hopefully be avoided through victory in Iraq.
New Home Sales Rise Beyond The One-Million Mark in April
Sales of new single-family homes rose 1.7% in April to a seasonally adjusted annual rate of 1.03 million units, according to the Commerce Department. It is the third time this year that new-home sales went above the million-unit mark. New-home sales rose in three out of four regions in April, with gains of 13.4%, 0.6%, and 4.3% recorded in the Midwest, South, and West, respectively. In the Northeast, where shifting weather patterns have caused wild fluctuations for several months, sales fell nearly 18%. “Sales of both new and existing homes were slightly above their first quarter averages in April, and the fundamentals of this housing market continue to exhibit remarkable strength looking forward,” notes David Seiders, chief economist, National Association of Home Builders (NAHB).
Getting the Most Out Of Your Cylinders
Dr. Heather Brown, Ph.D. Associate Professor, Concrete Industry Management Program Middle Tennessee State University
What could possibly go wrong? The better question to ask when talking about accurate cylinder breaks is what can’t go wrong. 6” by 12” concrete cylinders are the standard of checking in-place compressive strength for job performance, acceptance, checking mix proportion adequacy and gathering strength data for future quality control. The measured results are dependent upon adhering strictly to standardized uniform procedures, as outlined in ASTM C31 (casting cylinders), ASTM C617 (capping cylinders), ASTM C39 (breaking cylinders) and various other prescribed testing protocols. It is not surprising that problems can arise from failure to adhere to these various specifications and it is very important to realize that nearly all testing errors produce lower strength results. Some consequences of falsely low results are unnecessary delays, costly follow up testing, wasteful over-design and rejection of good concrete.
Here are some key steps that must be properly completed to insure accurate 28-day cylinder breaks.
• Sampling – technicians are required to obtain at least two portions from the middle third of the load. Remixing ensures consistency of the sample. Adhering to the maximum interval of fifteen minutes between obtaining the sample and casting the cylinders is important. Each set of cylinders must come from a single truck.
• Casting – technicians must choose the appropriate mold material, properly fill and consolidate cylinder molds, and ensure both good end condition and cylinder uniformity.
• Initial curing – this is critical to the accuracy of a cylinder. Temperatures lower than the specification (60-80 degrees F) can cause up to 7% loss in strength while exposure to freezing temps can cause up to 56% strength loss. High temperatures may boost early strengths but 28-day strengths will suffer. Cylinders must be properly stored in the field, in an environment that insures both proper temperature and moisture conditions and should be brought into the lab within 48 hours of casting
• Transporting cylinders – improper timing of moving cylinders can cause a loss of up to 7% in compressive strength. Proper handling during transport also prevents loss of cylinder strength.
• Laboratory curing – Wet curing in a 73 +/- 3 degree F environment maximizes the hydration of the cement, and is required by the specifications. This curing should begin as soon as cylinders are received in the lab and continue until the time for breaking the cylinder.
• Capping – this involves paying attention to the end condition and the capping material. The capped ends must be flat, perpendicular to the specimen axis, parallel to each other and not excessively thick. The capping material should not induce a stress distribution in the cylinder that would cause inaccurate measured results.
• Testing – this step involves attributes of the compression machine such as loading rate, specimen misalignment, loading platens, seating behavior and machine calibration. To ensure a properly working machine, refer to ASTM C39 for rules to check compliance.
• Reporting – the last step is to properly record the results of the test, including a post-failure inspection report on the type of cylinder break. Dissemination of the results to all parties, including the ready mix producer, is essential to identify any problem areas and to confirm successful mix performance.
The table shown below is an example of how many things can actually affect the strength of a cylinder. To get more detailed information about these variables, there is information in an NRMCA Publication No. 179 by David N. Richardson.
Testing Concrete
The concrete testing process garners little attention from the construction industry – until a problem occurs. At that point, everyone is intensely interested and all the parties involved become, for the most part, adversaries.
Here’s a true example from a personal experience. A commercial project with a lot of structural concrete allowed the general contractor to do the concrete testing. Subsequently, the GC assigned this responsibility to a laborer who had not received the proper training (and who was not ACI certified). Not surprisingly, several cylinders were not prepared according to the specification, resulting in some cylinders that displayed extensive honeycombs (voids) when the molds were removed. Instead of rejecting these cylinders due to their obvious lack of proper consolidation, the engineering firm allowed the cylinders to be broken, and then held up the job when the cylinders failed to make the required strength. The burden of proving that the inplace concrete met the strength specification now fell on me (the ready mix producer), in spite of the very obvious fact that this responsibility was being transferred to me on the basis of defective, non-standard cylinders. Subsequent coring demonstrated the in-place concrete strength to be fine, and GC had to foot the bill for several thousand dollars of coring expense, plus the delay to the job.
Procedures and specifications for concrete testing are well defined and generally accepted by all parties as fair and reasonable – the problem occurs when these well-defined specifications are not followed throughout the testing process. Unfortunately, failure to follow the mandated specifications is often more common than compliance. This problem is exacerbated when non-standard cylinders are allowed to be tested instead of being immediately rejected.
The following story highlights some of the most common problems encountered at various stages in the process. Armed with this important information, resolve to eliminate these specification violations from your next (or even your existing) projects – everyone will benefit.
