Ana Mafalda Matos

Durability Enhancement Of SCC With Waste Glass Powder

Self compacting concrete (SCC) requires a large quantity of fine materials compared to common concrete. In this work waste glass powder was used to replace (50%) of filler required. Two types of SCC were manufactured, a control SCC type (CTL) using cement and limestone filler and another with glass powder replacing 50% of the filler. Mechanical and durability properties, namely, compressive strength, resistivity, chloride ion penetration, carbonation, capillary water absorption and oxygen permeability were assessed on both SCC types. It could be concluded that waste glass powder can be used successfully in SCC improving chloride penetration and water absorption by capillarity and maintaining strength levels. The potential risk of alkali-silica observed on mortar was mitigated when incorporating glass powder.

Strength and Durability of Mortar Using Cork Waste Ash as Cement Replacement

Cork powder, the major waste from cork processing industries, is generated from grinding, cutting and finishing operations throughout the industrial cork process. Cork powder has been used mainly as fuel in cork industries. Cork waste ash is usually landfilled but if efficiently used in cement based construction materials it could contribute to sustainability. Strength and durability testing was undergone on mortar with 10 and 20% cement replacement with cork waste ash. Although strength is acceptable for 10% cement replacement with cork ash (5% loss at 90 days, compared to control), most durability properties (tested up to 6 months according to test type) reduced performance probably due to a broader pore structure caused by coarse particles in the ash which tested non pozzolanic. Moreover, cork waste ash does not present the necessary requirements in terms of chemical properties considering several standards. Present work has revealed that this cork waste cannot be used as a pozzolan or as a filler in cement based materials. In fact it is known that chemical composition of biomass ash is highly variable due to moisture variations, ash yield and different genetic types of inorganic matter in biomass and therefore it is important to pinpoint which types of biomass waste are adequate or not to use as cement replacement in construction.

Strength, ASR and Chloride Penetration of Mortar with Granite Waste Powder

Over the last decades, extensive research has been undertaken to minimize the use of Portland cement by increasing the amount of various supplementary cementing materials since currently global concrete production accounts for more than five percent of anthropogenic carbon dioxide emissions. The granite cutting industry produces large amounts of wastes. Managing large amounts of sludge can be rather problematic for its producers, which must find appropriate places for storage and deposition. The experimental program carried out involved characterization of granite dust from a quarry in the north of Portugal, including chemical analysis, scanning electron microscopy (SEM) and laser particle size analysis. Subsequently, mechanical and durability properties (alkali-silica reaction and resistance to penetration of chloride ions) were evaluated in mortar produced with different dosages of cement replacement, as well as, different levels of fineness of ground granite. It could be concluded that finely ground granite dust can originate a denser cement matrix and improve durability without compromising fresh behavior or strength.