The Influence of the Sodium Silicate Admixture on the Pumped Concrete Flowability in Pipelines / Natrio Silikato Tirpalo Priedo Poveikis Siurbliais Transportuojamo Betono Mišinio Tekamumui Vamzdžiais

In the research experimental studies of the effect sodium silicate solution (NST) and plasticizer admixtures have on concrete mixture pipe flow velocity and capacity during of the transportation of mixtures with the “S”-type valve concrete pump with two pistons where carried out. The filling time of 0.406 m³ volume foundation blocks forms of concrete mixture at different concrete mix pump supply pressures (25.5 and 68.0 bar) was measured. It was found that the addition to the mixture of NST 0.5% by weight of cement with superplasticizer based on polycarboxylic ethers, increases the flow rate of the mixture in the pipeline, and performance with a lower concrete mix pump supply pressure. With 0.5% NST of the cement mass with lignosulphonate plasticizer and reduced amount of cement in concrete mix, the flowability in pipeline with a low concrete mix pump delivery pressure (25.5 bar) is worse. With 0.5% NST of the cement mass with lignosulphonate plasticizer, using only 0/4 fraction sand, concrete mix transportation in mixture pipeline at low concrete mix pump delivery pressure (25.5 bar) is stopped. When the pump mix feed pressure is increased up to 68 bar, the mixture flows through the pipeline again. The investigation has shown that sodium silicate solution admixture interaction together with different chemical compositions plasticizers affects the mixture flowability in pipes.