Strength Contest


    The purpose of this contest is for each lab group to make the strongest possible concrete, by making use of what they have learned in the course. They have access to a wide variety of ingredients and are free to design their own recipe and procedure. There are two categories: Raw Strength and Economy. To win for Raw Strength, each group tries to achieve the maximum tensile strength, regardless of the cost of the ingredients. In the Economy category, the tensile strength is divided by the cost per kilogram of the material (calculated using the list of prices shown below, which is a few years old). The winners this year reached tensile strengths of 10 MPa (~1450 psi)!

                           Materials Costs

                 Material                   Cost ( $ / kg )

             3/8 aggregate                   0.023

             sand                                  0.018

             cement                              0.077

             blast furnace slag              0.046

             fly ash                               0.033

             silica fume                        0.88

             nylon fibers                       1.81

             superplasticizer                 2.11

             air entrainment                  0.80

© Princeton University 2012