Evaluation of the physical-mechanical properties of cement-lime based masonry mortars produced with mixed recycled aggregates

Abstract

This study investigated the physical-mechanical effects of cement-lime mortars containing recycled aggregate of construction and demolition waste (CDW). The natural aggregate (NA) was replaced by volume at 25%, 50%, 75% and 100% by mixed recycled aggregate (MRA) obtained from the CDW crushing. Five types of mortars were prepared with a volumetric ratio of 1:1:6 (cement, lime and aggregate) and water/binder ratio based on the fixed consistency of 260 mm. The effects of MRA on fresh and hardened mortars’ properties were analyzed. The results were analyzed using a one-way ANOVA. MRA incorporation improved most of the physical-mechanical properties of mortars tested, except for hardened bulk density, water absorption and porosity. In the long-run, mechanical strengths significantly increased in all compositions, especially those with higher percentages of MRA. The results obtained showed that the use of MRA in masonry mortars is an alternative to reduce the generation of waste and consumption of natural resources.

Characterization and Analysis of the Carbonation Process of a Lime Mortar Obtained from Phosphogypsum Waste

“…They represent a relevant data that directly influences the viscosity and therefore the workability of the mixture. In our case, we observed densities of 2140 kg/m 3 and 3% occluded air for M185 and 2120 kg/m 3 and 3.25% occluded air for M200 [ 32 ].…”

Elevated Temperature Performance of Reactive Powder Concrete Containing Recycled Fine Aggregates

“…This increase was probably due to the internal curing effect of RFA, where initially absorbed water in the pores of recycled materials became available at a later age to promote further hydration process of cementitious materials [ 35 , 36 , 82 ]. The second reason was the filler effect, caused by the finer fraction of RFA, whose size was even smaller than natural sand, and subsequently, its greater specific surface area [ 45 , 83 , 84 ], resulted in filling the micro gaps of concrete making it denser and more compact, which helped to prevent early propagation of cracks. Additionally, the roughness and more irregular shape of RFA particles contribute to reinforce the transition zone of the recycled concrete, leading to a stronger bond with the cement paste [ 82 , 85 ].…”

Effects of Particle Size Distribution of Standard Sands on the Physical-Mechanical Properties of Mortars

“…As the complementary binder, hydrated-lime (HL) type CH-I (similar to ASTM C207-6) with a specific gravity of 2.30 g/cm 3 , bulk density of 0.56 g/cm 3 and CaO and MgO oxide contents higher than 95% were used. The use of HL is justified by its beneficial effect on mortar properties (such as workability, water retention, and ability to absorb deformations) and by reducing cement consumption [ 24 , 25 , 26 , 27 ], contributing to minimizing environmental impacts from clinker production.…”

“…The following criteria were established to produce the mortars: Maintain the mixing proportion of 1:1:6 by weight of Portland cement, hydrated lime, and sand for all mixtures, respectively. The choice of this mixture proportion was due to its wide use in civil construction works in the region and because it is a mixing ratio used in previous research [ 25 , 26 , 27 ]; Mortars are mixed in a mortar, according to NBR 16541 [ 36 ] The production of three types of mortar: MSS25 (reference), MSS30-20 and MSS40-10; The consistency index of the mortars was kept constant at 260 mm in all mixtures according to NBR 16541 [ 36 ]; The ideal amount of water for mortar mixture was determined experimentally to ensure workability. The procedures adopted followed the specifications of NBR 13,276 [ 37 ] …”