Prevention of Autogenous Shrinkage in High-Strength Mortars with Saturated Tea Waste Particles

Abstract

The purpose of this study was to prevent early age autogenous shrinkage in high-strength mortars with saturated tea waste particles. In general, high strength and high performance concretes are made with low water/binder ratios; hence, they are susceptible to shrink at early ages. This shrinkage occurs due to self-desiccation that leads to autogenous shrinkage. To overcome self-desiccation problems in high-strength cement composites, it is necessary to keep the composites moist for a long time. Pre-saturated porous lightweight aggregates and super absorbent polymers are the most commonly used materials in high-strength cement composites to keep them moist for a long time; however, in this study, porous tea waste particles were used to keep the cement mortars moist. Pre-saturated tea waste particles were used in two different size proportions, making up as much as 3% of the volume of the binder. Moreover, commonly used lightweight aggregate (perlite) was also used to compare the outcomes of specimens made with tea waste particles. Different parameters were observed, such as, flow of fresh mortars, autogenous shrinkage, mechanical strengths and microstructure of specimens. The addition of tea waste and perlite particles in mortars made with Ordinary Portland cement (OPC) as the only binder, showed a reduction in flow, autogenous shrinkage and mechanical strengths, as compared to mixes made with partial addition of silica fume. Although, the use of silica fume improved the mechanical strength of specimens. Moreover, the use of saturated tea waste and perlite particles also improved the microstructure of specimens at an age of 28 days. The results revealed that the saturated tea waste particles have the ability to prevent autogenous shrinkage but they reduce strength of high-strength mortars at early ages.

Investigation the effect of nanocarbon tube prepared from tea waste on microstructure and properties of cement mortar

“…From the results obtained, it can be seen that the workability increased by 16% and 10% at higher percentages of replacement of 3% and 4%, respectively. These results are consistent with those of previous studies in which a decrease in slump was demonstrated (Jakhrani et al 2019;Fang et al 2022). According to (Fang et al 2022) the primary results of previous studies showed that the workability of mortar containing tea waste as a cement substitute was increased due to the high neness of tea waste and the treatment process for tea waste before use compared to owing mortar without tea waste.…”