The aim of this study is to develop Lightweight self-compacting concrete (LWSCC) mixtures using locally sourced waste materials such as Expanded Polystyrene Beads (EPS) and Waste Plastic Fibers (WPFs) which are all available abundantly available in Republic of Iraq at little or no cost. The fresh, hardened and mechanical properties of these LWSCC were studied, followed by results analysis. Five different mixes of LWSCC were prepared in term of WPF content (0.25, 0.5, 0.75, 1.0, and 1.25 %), in addition to the control mix (R mix) and lightweight concrete (E mix) made of EPS content as a replacement of coarse aggregate. The study showed that the LWSCC produced with these waste materials were decreased the density (lightweight) of the concrete mixes as EPS tend to form more clumps, absorb water and make the mix dry. Therefore, concrete mixtures were adjusted accordingly to be able to offset the workability caused by the addition of EPS. The increase in WPF content decreased the workability due to clumping that occurred in the mixing phase. The analysis of mechanical properties of the LWSCFRC specimens revealed that there was not much improvement. While LWSCC with 100% of EPS replacement as coarse aggregates and 1.25% WPFs provides the best flexural toughness performance
Fresh and hardened properties of self-compacting concrete was experimentally examined by replacing different percentages of cement by soft clay powder, which resulting from crushing the wastes of clay bricks. Three percentages (5%, 10%, and 15%) of cement were replaced with clay powder to study their effect on the properties of cement mortar and concrete of Grade (C35) in both fresh and hardened states. It was found that development rates of the compressive and tensile strengths for the mortar between ages of 7 to 28 days, decreased with increasing the percentage of the clay powder. Compared to the mix without clay powder, it was found that replacing (5%) from the cement causes a significant increase in the workability of the self-compacting concrete and the properties of the resulting hardened concrete such as compressive strength, tensile strength, and modulus of elasticity. While using (10%) and (15%) of the clay powder causes a significant decrease in the workability of the fresh concrete and the properties of the hardened concrete compared to mix without clay powder.
AbstractThis study aims to investigate the properties of SCC produced by locally availablematerials , and attempts have been made to increase the range of grading of fineaggregate, with fineness modulus ranging from (1.5 to 4.1) , and to study the effect of themaximum size of coarse aggregate . It also aims to study the influence of High ReactivityMetakaolin (HRM) as a partial replacement by weight of cement on the properties of freshand hardened SCC, 24 different mixes of SCC are prepared .8 mixes are considered asReference mixes which are used for comparison purposes. To determine the workability,different test methods were adopted such as slump flow, V-funnel, and L-box tests. Whenfineness modulus of fine aggregate and maximum size of coarse aggregate increase,flowability, passing ability and segregation resistance decrease as compared with smallmaximum size of aggregate and other fineness modulus. Further more, the inclusion of10% HRM as a partial replacement by weight of cement leads to decrease flow ability andincrease of viscosity. The fineness modulus (3.1) of fine aggregate gives better resultsthan other fineness modulus. The results obtained from this study, also show that it ispossible to produce SCC from local available materials which satisfy the requirement ofthis type of concrete. Moreover, the results show the possibility of using different gradingof fine aggregate with fineness modulus ranging from (1.5 to 4.1) and the effect ofchange in fineness modulus is not significant on hardened concrete properties , while it ismore significant on fresh concrete properties .