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The Concrete Times April 2015

The CONCRETE Times • APR 2015 monthly columnist - jay shilstone 15 We’ve seen the economy come to a screeching halt with the Arab Oil Embargo. Road that were built in the mid- 1970s start to fall apart 10 years later. Our ageing infrastructure is starting to deteriorate. In looking back over the last 50 years in concrete nothing has really changed except the introduction of air entrainment. Now we are starting to see concrete pumps, superplasticizers and fly ash. Certain parts of the country are starting to run out of the best materials for concrete. We look up from our compression machines and slump cones and realize that we have lost sight of one of our goals – to make good concrete. Our industry is composed of truckers who happen to ship concrete. Many don’t understand the product they are making. For 50 years, when we only dealt with rock, sand, cement and water, it was easy for college-educated engineers to learn more about concrete than the people who made it. These Engineers and designers have implemented practices to protect themselves from ignorant or malicious producers. The adversarial relationship has become fully entrenched. What happened in Europe? Again, I don’t guarantee this is the case, but it seems to fit. Let’s look at Europe. With its history of feudalism, lords and ladies and royalty, it is easy to see how large corporations like Krupp, Thyssen, Siemens and Daimler came to be. Using vast inherited fortunes Dukes and Counts became captains of industry. A more concentrated land mass and population, with correspondingly fewer resources, made it more imperative to develop and efficient infrastructure. An industrial complex was formed that almost made it possible for a country half the size of Texas to almost conquer Western civilization. Then, with the end of World War II, it all came crashing down. Europe’s ability to make cement and concrete was practically destroyed. Everything had to be rebuilt from scratch. And as long as they were going to rebuild it, why not build it better? The whole concrete industry was rebuilt to make more efficient use of materials, land and manpower. Many of the technologies we use today were born or fostered in Europe. Concrete pumps and superplasticizers came to the New World from the Old Country. Concrete batch plants were built containing 5 or more aggregate bins to promote efficient blending of aggregates to reduce water and cement. Quality control measures were put into place to insure that concrete that was produced would not have to be rejected. The Autobahn was constructed using design/ build/maintain practices that we are just starting to implement in the U.S. now. Not only are these processes in place in Europe, they have also migrated to Australia and many parts of Latin America. The U.S. may have drive and a can-do attitude, but Europe has science and technology. Where do we go from here? The concrete industry in the U.S. needs to be rebooted into “Ready Mix 2.0”. We need to catch up to the rest of the developed world when it comes to concrete production. In order to accomplish this we need to do the following: Let (or force) concrete producers to handle their own quality control. If you go into Ford Motor Company and tell them you want to do QC on the car they are building for you I guarantee you won’t get past the gate. This is not a case of the fox guarding the henhouse. This is a case of a professional company putting out a product that performs as advertised. Owners can still do quality assurance testing, but let the concrete producer do the real QC. Producer QC departments would become certified to make certain that they perform capably and responsibly. Get rid of fixed-weight concrete recipes and allow the producer to change materials and weights as needed to produce more uniform concrete. If you were to walk into a cement plant on Jan. 1 and tell them they had to use a fixed proportion of materials for the rest of the year they would laugh you out of the plant. Steel, paper, petrochemicals and foodstuffs are the same. The materials that come in today are not the same as those that will come in next week. We need to adjust accordingly. Designers should specify concrete based on performance, not prescriptive requirements. Admittedly some performance requirements we can’t yet define but we are getting better at it. I know there is concern in the slab industry about issues such as curling, shrinkage and segregation, but if a design/ build/maintain approach or a partnering technique can be implemented where all parties share in the risk and reward, maybe improvements can be made to that process. Replace or retrofit batch plants with just 2 or 3 aggregate bins to allow the use of 5 or more aggregates in a single


The Concrete Times April 2015
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