Effect of waste marble powder and glass fiber on the carbonation of concrete

In this study, the effect of waste marble powder and glass fiber additive on carbonation of concrete has been investigated. 25 different concrete series has been prepared by substituting glass fiber and filler material by weight of 0,25 , 0,50, 0,75 and 1 kg/m3 with 25%, 50%, 75% and 100% waste marble powder by volume. Since the process of carbonation takes long years, accelerated carbonation test technique has been used in laboratory environment. Carbonation depths have been measured by electronic caliper with phenolphthalein indicator prepared in 1% ethyl alcohol. Each series have been kept in gas proof tank in media with 40% carbon dioxide for different time periods (7, 14 and 28 days) to support the relationship between carbonation depths and to make comparisons. Porosity, capillary absorption, ultrasonic pulse velocity, compressive strengths and splitting tensile strength tests have been performed on the specimens that completed 28-day curing period, before and after carbonation. Microstructures of the specimens that has been subjected to tests has been analyzed by SEM images and supported by EDX. According to the results we obtained, porosity, capillarity, compressive and splitting tensile strength values of the specimens have decreased after carbonation test, while ultrasonic pulse velocity values have increased. Carbonation depth has increased in parallel to the increase of time factor. In addition, comparison of each series have revealed that ultrasonic pulse velocity, compressive and splitting tensile strength values of glass fiber reinforced concrete specimens have increased with the increase of marble powder, while porosity, capillary absorption and carbonation depth values have decreased. On the other hand, increase of glass fiber have increased porosity, capillary absorption, splitting tensile strength and carbonation depth values and have decreased ultrasonic pulse velocity and compressive strength values.