Mechanical Properties of Concrete Containing Natural Zeolite Jaroslava KOŤÁTKOVÁ, Pavel REITERMAN Czech Technical University in Prague, Faculty of Civil Engineering, Experimental Centre, Thákurova 7, 166 26, Praha 6 Dejvice, Czech Republic jaroslava.kotakova@fsv.cvut.cz

Contents Motivation Characterization of natural zeolite Experimental program Results Conclusions

Motivation Development of HPC Use of supplementary cementitious materials in concrete Decrease in cement consumption Enhancement of mechanical properties and durability Availability, cost? Silica fume x natural zeolite → ternary binders

Natural zeolite Volcanic highly porous rock 3D structure of tetrahedras SiO4 and AlO4 Pozzolanic properties Interlinked channels of < 2 nm, ability of ion exchange Molecular sieve Sorbent Crystal structure of Na-clinoptilolite

Experimental program HPC Four fractions of silica aggregate (maximum size 4 mm) Inert filler – silica powder Cement CEM I 52.5 R Low w/c (0,21) + superplasticizer Silica fume 140 kg/m3 10 – 60 % cement replacement by natural zeolite Investigation of mechanical properties in time

Results – compressive strength

Results – flexural strength

Summary HPC with ternary binder system Compressive strength Silica fume + 10 - 60 % of natural zeolite as SCM Compressive strength Decrease with rising amount of NZ due to unreacted particles Visible rise after 1 year from manufacture – continuing pozzolanic reaction Flexural strength Slight decrease up to 180 days – microcracks late strength – pozzolanic reaction prevailed, highest values for 20% replacement level

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