EFFECT OF LIGHTWEIGHT AGGREGATES ADDITION ON THE RHEOLOGICAL PROPERTIES AND THE HARDENED STATE OF MORTARS

abstract

This paper evaluates the use of lightweight aggregates (LWA), namely perlite (PER) and vermiculite (VER) in cement mortars. The workability of mortars was defined in rheometer and flow table tests. Three distinct LWA levels were added (0-3, 4.5-7, and 9-10.5 wt%) requiring the use of distinct water/solids (W/S) ratios (0.18, 0.265 and 0.35, respectively). In order to evaluate the performance of such formulations in the hardened state, the flexural and compressive strength after 28 days curing was also measured. In general, LWA caused a high variation on the yield stress and spread on table, being the yield stress the best rheological parameter to be related with the flow table. PER exerts a strong impact on initial yield stress, while the effect of VER is stronger for longer rheology testing periods. The compressive strength ranged from 12.3 MPa (0% LWA) to 2.77 MPa (PER) and 2.39 MPa (VER).

keywords

EXPANDED PERLITE AGGREGATE; SELF-COMPACTING CONCRETE; THERMAL-CONDUCTIVITY; COMPRESSIVE STRENGTH; MINERAL ADMIXTURES; SLUMP; FLOW

subject category

Mechanics

authors

Senff, L; Hotza, D; Labrincha, JA

our authors

acknowledgements

The authors acknowledge the support of CAPES, Brazil. The authors also thank Weber Portugal, Elken (microssilica) and Basf (superplasticizer) for providing raw materials for this work.

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