Composition effect on the strength of modified expanded clay lightweight concrete

Abstract

The effect of modified expanded clay lightweight concrete on its strength is investigated. In the conducted on the optimal plan experiment, the four factors of the composition varied: amount of sulfate-resistant Portland cement from 500 to 600 kg/m3, amount of silica fume from 0 to 40 kg/m3, percentage of gravel in concrete from 650 to 700 l/m3, polypropylene fiber from 0 to 1,2 kg/m3. All mixtures had equal concrete-mix consistency P2, in all mixtures superplasticizer S-3 was introduced in the amount of 0,8%. It was established that the compressive strength of investigated concrete was in the range of 34 to 45 MPa and bending tension strength in the range from 5.8 to 7.2 MPa. The greatest strength of the concrete mix with the amount of silica fume 30-35 kg/m3 and with the content of expanded clay gravel 660-680 l/m3. Due the addition of fiber increases the bending tension strength, while the compressive strength is practically unchanged. Investigated expanded clay lightweight concrete can be recommended for thin-walled constructions of civil buildings also for transport and hydrotechnical floating structures.