scholarly journals Fresh and hardened properties of lightweight self-compacting concrete containing walnut shells as coarse aggregate

Author(s):  
Nahla Naji Hilal ◽  
Mohammed Freeh Sahab ◽  
Taghreed Khaleefa Mohammed Ali
2018 ◽  
Vol 877 ◽  
pp. 248-253
Author(s):  
Thete Swapnil Tanajirao ◽  
D. Arpitha ◽  
Suman Saha ◽  
C. Rajasekaran

Large quantity of the quarry dust gets produced annually in the quarries during the extraction of the crushed coarse aggregate. As a result, disposal problems of this material gain significant momentum as these disturb environmental systems also. Now-a-days many of the countries like India is facing problems of ban on the extraction of sand and lacunae in procuring of fine aggregate, which is important constituent of the concrete. To overcome this problem, present study is focused on the suitability to utilize the quarry dust in Self Compacting Concrete (SCC) partially as fine aggregate with the natural fine aggregates. In this work, quarry dust is used as replacement of sand in a different level (0%, 15%, 30%, 45% and 60%) for producing the SCC. Fresh properties such as slump flow and V-funnel time have been measured for all mixes and hardened properties as compressive strength, splitting tensile strength and flexural strength of the concrete have been checked for all the mixes and it has been found that optimum utilization of quarry dust up to 30% can been done to produce SCC without compromising with its properties.


This paper explains the combined effect of granite cutting waste and recycled concrete on the workability and mechanical properties of self compacting concrete. Experimental plan is divided in such a way that granite cutting waste is replaced with fine aggregate at 0, 20,40,60,80 and 100% proportions. Recycled concrete is replaced with the coarse aggregate starting from 20 to 100%. Total 36 mixes were designed to check the fresh and hardened properties. Slump flow and T500, v-funnel and L-box test are conducted to know the flow ability and passing ability of concrete. To study the hardened properties compressive strength, flexural strength test values are to be collected.


2019 ◽  
Vol 8 (3) ◽  
pp. 5140-5146

All over the world, wide amount of demolishing waste is being generated posing lot of environmental issues. To address these issues, Self-Compacting Concrete (SCC) was made by replacing cement partially with mineral admixtures and NCA with RCA. The fresh and hardened properties for M30 grade of SCC made with NCA and RCA were evaluated. Cement in SCC was recouped partly with 30% Fly Ash, 20% GGBS by weight of the cement. Polypropylene fibers at 0.1% were added to study their influencing nature on the hardened state and fresh state properties of the SCC mix. Four sequences of SCC mixes of M30 were prepared by substituting the NCA with RCA at 25%, 50%, 75% and 100% derived from the dismantled concrete waste of M30 parent grade. SCC produced with the RCA up to 50% and with 0.1% addition of Fibers demonstrated comparable performance as that of SCC with NCA.


Author(s):  
Mohamed Nagib Abou-Zeid ◽  
Mohamed Samir Roushdy

Self-compacting concrete (SCC) can be achieved by adjusting mix proportions and incorporating adequate admixtures, such as viscosity-modifying (VM) admixtures, with no vibration. Yet, the impact of the mix proportions and the role played by the VM admixtures as opposed to those played by superplasticizer admixtures are not fully understood. There also seems to be no unique means for assessment of such concrete, and the correlation between various tests needs further work. This study aims to achieve a better understanding of the influence of mix proportions on the properties of SCC. Twenty-six mixtures were prepared with various water-to-cementitious material ratios, fine aggregate-to-coarse aggregate ratios, and admixture dosages. Fresh concrete tests, including slump flow, L-box, U-box, and hardened concrete tests, including hardened density, compressive and flexural strength, as well as the rebound hammer tests, were performed. The uniformity of SCC properties among the column specimens was examined. The results revealed that adjustment of the mix proportions has a major impact on the fresh and hardened properties of SCC. The fresh concrete tests were found to correlate well with one another, and the SCC strength was comparable to that of reference concrete made with mechanical vibration. Yet, the components of the SCC examined exhibited a remarkable uniformity of properties. Further work that should involve large specimens in which concrete properties are evaluated in various locations is needed.


The use of recycled aggregate in any concrete saves the virgin coarse and fine aggregates to create for the production of concrete. This concept will deliver an ecofriendly, reduced eviction of natural resources and produce a green concrete concept. Coarse aggregate consists of more than 60% of total volume in ordinary concrete but only 40% is required for Self Compacting Concrete (SCC) by weight. Demolished concrete wastes which are crushed and sieved to the size are used as substitute for natural coarse aggregates. In this paper natural coarse aggregate in self-compacting concrete is replaced with 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% & 100% recycled aggregates in mix design. Furthermore, a detailed study on workability and hardened properties of specially proportioned mixes are also carried out and satisfactory results are obtained. Thus the derived SCC can come up with reduced CO2 emissions, economical and energy saving with all additional well-known advantages of fluid concrete.


Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 267
Author(s):  
Tomasz Rudnicki

The article presents a new functional method of designing self-compacting concrete (SCC). The assumptions of the functional method of designing self-compacting concrete were based on the double coating assumption (i.e., it was assumed that the grains of coarse aggregate were coated with a layer of cement mortar, whereas the grains of sand with cement paste). The proposed method is composed of four stages, each of which is responsible for the selection of a different component of the concrete mix. The proposed designing procedure takes into consideration such a selection of the mineral skeleton in terms of the volumetric saturation of the mineral skeleton, which prevents the blocking of aggregate grains, and the designed liquid phase demonstrated high structural viscosity and low yield stress. The performed experimental studies, the simulation of the elaborated mathematical model fully allowed for the verification of the theoretical assumptions that are the basis for the development of the method of designing self-compacting concrete.


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