As a concrete precaster we deal with specifications every day, mainly because we make our own concrete that goes into the products we make. Further, we want to make sure that you get what you pay for and expect with your investment.
So, here is a little issue that we all should be aware of. It has to do with the strength of the concrete as specified in those specifications. For example, we may have a product that states that we need to have a minimum strength of 4000 psi. That is fine, but I would hope that you never get concrete that is exactly the psi requirement the specs state. The reason is statistics, and when you test things and get values, averages say you will exceed specs 50% of the time and fail to meet specs 50% of the time. In our example of 4000 psi, you can expect not get 4000 psi half of the time; so much for your investment.
How do we solve this is really simple, we make the concrete stronger to make sure we exceed the specified value by some amount in order to make sure statistics do not make us fall below the specified value. This will be particularly important when you keep good records of past test results for a given concrete mix. Hawk Construction uses a specific formula regardless of how many test results we keep. This ensures that we will not only exceed the specification, but provides additional benefits that goes along with having strong concrete. For example, we recently set a record compression test of 10,691 psi at a 28-days interval on one our high strength mixes. It was not really intended to be that high, but through proper mix design, aggregates, chemicals, curing and just plainly caring about making concrete, we were able to obtain these readings. Just as information, as of the date of this writing, we are typically just under 4000 psi every morning on our strength tests; this is just short of a typical 4000 psi reading in 28-days.
As a buyer of precast, we assume you want a good product for your investment. Hawk Construction understands this and has no issue proving concrete strength. This is an added value to you, the customer, since working with us is working not only with an installer of concrete fencing, but we are also the manufacturer. I always challenge customers to ask our other competitors about their concrete and what they are getting for their investment. Its unfortunate to hear that some fence providers either do not know, state they get it from a redi-mix supplier and leave it to them, or just repeat the specifications they were given from a piece of paper.
Hawk Construction has no issue telling you whats in our concrete and what you can expect from it. We genuinely understand investment and we encourage our customers to ask other fence providers these questions and have them prove their specifications.
Below is a fantastic demonstration of simply proving wind load and the strength of our products. The panel below that we produce is laid flat and is laying on a couple concrete columns, at the edges, additionally, we have removed all rebar and reinforcement from the panel; it is solely concrete only. When placing a concrete panel in this position, it essentially passes the building code requirements for wind loading, but we went further. We continued by stacking concrete blocks on it until it broke. That would be several thousand pounds of additional weight on the panel, exceeding wind load standards by a rather large margin.
With that said, we suggest you ask any other concrete fence supplier what is exactly in the concrete that makes up their screen wall or retaining block and see if that meets your expectation and if its worth your investment. Those long pauses before you can get answer should be a flag of caution.