Block Ready Mix Group P.O. Box 280 1414 Mississippi Blvd. Bettendorf, IA 52722

Dispatch Phone (563) 884-4117 Fax (563) 884-4037

At W. G. Block we pride ourselves on providing excellent customer support.  Our Quality Control department offers a variety of services such as: Concrete testing for air content, slump tests, and strength test cylinders performed b our ACI certified field grade technicians.  All of our technicians are also Illinois and Iowa DOT certified and trained to make adjustments to the concrete on site if the need would arise.

Our quality control technicians also help with truck safety on site by providing information for drivers such as truck placement requirements and any on site hazards to help minimize the potential for accidents.

W. G. Block has a fully certified lab with the capability to perform tests on all of our materials.  Some of the tests performed by our technicians include gradations on all fine and course aggregates, maturity  tests, initial set tests, standard deviation recording on strength test cylinders, yield test, and spec mix proportion testing.

Our quality control department performs as many tests as possible to ensure we are producing the highest quality product.  We currently have three quality control technicians and a quality control manager with a total combined experience of 26 years.  In the ready mix business all of our QC techs are cross trained in all areas of concrete production such as, dispatching, batching, plant maintenance, and operation of ready mix trucks.

	Air Test- Air test are performed to determine the amount of entrained air in any given concrete mix. Each mix, depending on the project, has a target amount of entrained air to be used. A typical outdoor mix has a target air percentage of 5-8%, of the volume of concrete. Developed in the 1930’s air entrainment is recommended for nearly all concrete mixes. It was developed to improve resistance to freezing when exposed to water and deicing chemicals. Air-entrained concrete contains billions of microscopic cells that relieve internal pressure on the concrete by providing tiny chambers for the expansion of water as it freezes. The benefits of entrained air are: improved resistance to severe frost action freeze/thaw cycles, resistance to cycles of wetting and drying, and increased workability and durability.
	Aggregate Gradations- Gradations of aggregates significantly affect concrete mixture proportioning and workability. Gradation tests are an important element in the assurance of quality concrete. The grading or size distribution on an aggregate is determined by a sieve analysis test in which the particles are divided into their various sizes by standard sieves. Results of sieve analyses are used in three ways: (1) to determine whether or not the materials meet specifications; (2) to select the most suitable material if several aggregates are available; and (3) to detect variations in grading that are sufficient to warrant blending selected sizes or an adjustment of concrete mix proportions.
	Strength Testing - Concrete mixtures can be designed to provide a wide range of mechanical and durability properties to meet the design requirements of a structure. The compressive strength of concrete is the most common performance measure used by the engineer in designing buildings and other structures. The compressive strength is measured by breaking concrete cylinders in a compression-testing machine. Concrete compressive strength requirements can vary from 2500 psi for residential concrete to 4000 psi and much higher in commercial structures. WHY is Compressive Strength Determined? Compressive strength test results are primarily used to determine that the concrete mixture as delivered meets the requirements of the specified strength in the job specification. Strength test results from cast cylinders may be used for quality control, acceptance of concrete, estimating the concrete strength in a structure for the purpose of scheduling construction operations such as form removal, or for evaluating the adequacy of curing and protection afforded to the structure. A test result is the average of at least two standard-cured strength specimens made from the same concrete sample and tested at the same age. In most cases, strength requirements for concrete are at an age of 28 days.
	Maturity Testing- Is a technique used to determine the effects of time and temperature on the strength development of concrete. The method allows us to make reliable estimates of in-place strength of concrete during construction. The Maturity Method for concrete construction dates back to the late 1940’s and early 1950’s based on a steam curing technique used in England. A construction tragedy in 1973 sparked the interest of The National Bureau of Standards and OSHA.  The findings triggered the relatively new approach to measuring in-place strength development under variable temperature conditions, known as the Maturity Method, which the state of Iowa has adopted as a standard measurement for Highway and Bridge Construction. Maturity can directly indicate the in-place strength of concrete, and can be monitored continuously, so you know the strength in real time, even at early ages. By running Maturity Test, our contractors are able to strip forms sooner, and with confidence that the concrete will not fail. They are also able to allow traffic onto new concrete surfaces as soon as the desired strength is attained. It allows contractors to get paid sooner and reduce worker hours, and this method reduces the number of test cylinders or beams, that must be made. For additional information on Maturity Testing please contact one of the Quality Control Technicians at Block Ready Mix Group.

Your New Driveway or Sidewalk:

First Year Care:
Concrete continues to gain strength throughout its service life. Early in this life, special care must be taken by the owner to enable strength gain and to ensure the greatest long term durability possible. The following guidelines will help you get the most from your concrete investment:

-Do not drive on or over new concrete for at least three days.
-Do not allow drain water to undermine the slab and cause settlement cracks.
-Do not allow snow or ice to accumulate on the slab during the first winter after it is placed. Snow should never be piled or plowed onto a new concrete slab. Plow or shovel snow off as soon as possible.
-Do not use de-icing chemicals, such as salt or calcium chloride, on new concrete during the first winter. Traction can be provided by using sand.
-Never use de-icers containing fertilizer ingredients such as ammonium sulfate or ammonium nitrate.
-Protect new concrete from exposure to liquid fertilizer systems used for lawn treatment.

Common Concerns:
-Pop-Outs: Concrete is a blend of natural material. Therefore, it may have some natural imperfections like pop-outs. Many times small rock particles that do not adhere well on the surface of concrete will find their way into the mix. This can cause small chips or “pop-outs” in the surface of the finished product. These imperfections rarely effect long-term durability.

Non-Uniform Appearance: Concrete changes color as it matures. Variations of light and dark areas over the first month are normal. In fact, a darker color indicates retention of moisture which is a good sign. Eventually the color will lighten and even out.