International Concrete Abstracts Portal

Conventional portland cement concrete and concretes with latex and epoxy additives were prepared and tested for their microstructure characteristics using the scanning electron microscope (SEM). The chloride-ion penetration profiles were also studied on 10-cm concrete cubes that were immersed in 15 percent NaCl solution for 21 days. Following the 21-day soaking period and a subsequent 21-day air-drying period, concrete powder samples were removed by drilling at depth intervals of 0 to 12, 12 to 25, 25 to 38, and 38 to 50 mm and tested for acid-soluble chloride-ion content using a potentiometric titration procedure. The results of these investigations and typical micrographs are presented.

Polymer concretes using various polymeric binders are widely used as building materials, but it is generally considered that their thermal resistance and fire resistance are limited because of the thermally unstable and combustible polymeric binders used. This paper deals with the incombustibility of polyester and polymethyl methacrylate concretes made with wet aggregates by applying strength improvement techniques, including the addition of moisture absorptive additives, a silane-coupling agent, and steel fibers. The polyester and polymethyl methacrylate concretes are prepared with wet aggregates, moisture absorptive additives, a silane-coupling agent, and steel fibers. First, the concretes are tested for compressive strength to examine the effects of the applied strength improvement techniques. Then they are tested for incombustibility by the surface burning test specified in JIS A 1321 (Testing Method for Incombustibility of Internal Finish Material and Procedure of Buildings). It is concluded from the test results that the use of wet aggregates causes great improvement in the incombustibility of polyester concrete, but polymethyl methacrylate concrete with wet aggregates does not provide a good incombustibility because of the thermal decomposition of its binder at a relatively low temperature.

Polymer-modified concretes were subjected to four different curing methods to see the effects of various moisture conditions on their strength developments. Three epoxies and one latex were included in the investigation. One test series was prepared with each polymer and was then repeated with the addition of a chloride-free accelerator. The strength results were compared to strengths of concretes of the same composition but without polymer. The comparison shows that wet conditions do reduce the compressive strengths of polymer-modified concretes, the magnitude of which is greatly influenced by the quality of polymer used. These strength reductions, however, can be counterbalanced by a suitable accelerator.

One brand of polymer concrete beams reinforced with fiberglass rods were tested and evaluated in simple flexure. Testing was carried out by the applying of two equal loads symmetrically placed about the center line of the beam on simply supported spans of 51, 63, and 72 in. The distance of the load points from the center line of the beams was varied to change the available development length for the reinforcing rod. The primary experimental data consisted of strains measured by means of electrical resistance strain gages placed on the surface of the polymer concrete and along the reinforcing rod. These strains were used to establish cracking strains and bond strengths for the beams tested. The results indicate a range of values for cracking strains and bond strengths, the lowest cracking strain being 370 psi and the lowest bond strength, 434 psi.

Providing the latest advances in research, design and technology, this ACI symposium publication offers state-of-the-art information and greater insight into the latest use of polymer modified concrete and polymer concrete composites.A collection of 11 symposium papers, Polymer Modified Concrete deals exclusively with the various effects of polymers in concrete and provides an extensive source of reference. Bringing together expertise from around the world, case studies include: lightweight polymer concrete composites, polyester polymer concrete under flexural loading, flexure and bond in fiberglass-reinforced polymer concrete beams, and strength losses of polymer-modified concrete under wet conditions. Filled with illustrations, photos, and graphs, Polymer Modified Concrete provides in-depth answers to all of your questions. Note: The individual papers are also available as .pdf downloads.. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP99