Effect of Granulated Blast Furnace Slag and fly ash addition on the strength properties of lightweight mortars containing waste PET aggregates
Özet
In this work, the effect of Granulated Blast Furnace Slag (GBFS) and fly ash (FA) addition on the strength
properties of lightweight mortars containing waste Poly-ethylene Terephthalate (PET) bottle aggregates
was investigated. Investigation was carried out on three groups of mortar specimens. One made with only
Normal Portland cement (NPC) as binder, second made with NPC and GBFS together and, third made with
NPC and FA together. The industrial wastes mentioned above were used as the replacement of cement on
mass basis at the replacement ratio of 50%. The size of shredded PET granules used as aggregate for the
preparation of mortar mixtures were between 0 and 4 mm. The waste lightweight PET aggregate
(WPLA)–binder ratio (WPLA/b) was 0.60; the water–binder (w/b) ratios were determined as 0.45 and
0.50. The dry unit weight, compressive and flexural–tensile strengths, carbonation depths and drying
shrinkage values were measured and presented. The results have shown that modifying GBFS had positive effects on the compressive strength and drying shrinkage values (after 90 days) of the WPLA mortars.
However, FA substitution decreased compressive and flexural–tensile strengths and increased carbonation depths. Nevertheless a visible reduction occurred on the drying shrinkage values of FA modifying
specimens more than cement specimens and GBFS modified specimens. The test results indicated that,
GBFS has a potential of using as the replacement of cement on the WPLA mortars by taking into consideration the characteristics. But using FA as a binder at the replacement ratio of 50% did not improve the
overall strength properties. Although it was thought that, using FA as binder at the replacement ratio of
50% for the aim of production WPLA concrete which has a specific strength, would provide advantages of
economical and ecological aspects.
