Abstracts Book - IMRC 2018

• SF5-P067
MECHANICAL PROPERTIES OF LIGHTWEIGHT HYDRAULIC
CONCRETES FROM METALLURGICAL SLAGS AND ALUMINUM
RESIDUES
Ricardo Xicotencatl Magallanes Rivera 1 , Eduardo Cabello Ovalle 1 , Juan Carlos Ortiz Cuellar 1 ,
Marisol Gallardo Heredia 1 , Ulises Avila López 1
1 Universidad Autónoma de Coahuila, Facultad de Ingeniería, Mexico.
In this work, the mechanical properties of lightweight mortar specimens
prepared with Portland cement, recycled slags and waste aluminum powder
(AP) cured for up to 120 days were evaluated. Ordinary Portland cement
(strength class 40R) and blast-furnace, BOF or electric arc furnace (EAF) slags
were blended as hydraulic composite binders. Common calcareous sand was
used for the mortars after being sieved between the US meshes #20 and #30
(0.841-0.595 mm) to eliminate coarse particles, and AP from molds of the
ceramic industry was incorporated at 5% of the total mass of the binder. The
objective was to fabricate structural lightweight concretes from the chemical
reaction of Al 0 of the AP and calcium hydroxide from the hydrated products of
the binders to produce voids in the materials by the liberation and confinement
of gaseous hydrogen. Prismatic specimens (4x4x16 cm) were fabricated with an
aggregate:binder ratio of 2.75:1 at a constant water/binder=0.55 with good
workability. These were cured under water at 20°C and were mechanically
tested for module of rupture and compressive strength according ASTM C348
and ASTM C349. Results showed that it is possible to fabricate materials with
~27% of added porosity with the use of the AP in comparison with neat Portland
cement materials. Latter denoted a decrease in the density of almost 35%,
reducing from 2.39 to 1.56 g/cm 3 in relation to the AP free specimens. The
compressive and flexural strength of the mortars variated according the
formulation of the binders in 11.5-22.7 MPa and 1.5-3.3 MPa, respectively, after
120 days: the incorporation of 20% of blast-furnace slag developed the better
mechanical properties followed by the same addition of BOF and finally the EAF.
The results indicate that diminishes in strength were developed in a linear
relationship to the decrease in density, unlike the almost exponential behavior
commonly observed in structural concrete. The strength reached, is in some
cases even suitable for structural elements for edification with the advantages
of low density such as lower dead loads, insulation properties for
thermal/acoustic problems and economic transportation, with the inherent