Effect of various types and sizes of aggregate on self-compacting concrete (original) (raw)
Related papers
2011
This paper presents the key characteristics of fresh self-compacting concrete (SCC) made of five types of cements and coarse aggregates with different physical properties. The characteristics of SCC are evaluated in terms of viscosity, flowability, passing ability and segregation resistance of fresh concrete as per the European Guidelines for SCC. It is concluded that all key characteristics displayed changes depending on both the type of coarse aggregate and cement. Shape and morphological characteristics of the coarse aggregates like surface texture played significant role on the performance of fresh SCC. Mixes composed of gravel with smooth surface and spherical shape exhibited improved levels of the viscosity, flowability and passing ability of fresh SCC in comparison to crushed coarse aggregates with rough surfaces. Although the relative specific gravity and fineness of the cement influenced the characteristics some other factors can be responsible for the behavior of the SCC a...
The impact of coarse aggregate shape on the behavior of self-compacting high-performance concrete
E3S Web of Conferences, 2018
Self-Compacting High Performance Concrete (SCHPC) presents a crucial step in the development of concrete technology. The most important features of self-consolidating concrete are flowability, segregation resistance and passing ability. Generally, the rheological properties are modified by effective superplasticisers and water to binder ratio. The aim of this study is to focus on the important aspect of the impact of shape of the coarse aggregate on fresh concrete mixture properties, strength and deformability of SCHPC. Coarse aggregate is a significant proportion of the concrete volume and therefore has a meaningful influence on its quality. By appropriate selection of the shape of the grain aggregate, it is possible to affect the rheological parameters of concrete. The results presented in this study indicated that the shape of the grains of coarse aggregate has an impact on the strength and stiffness of SCHPC. Moreover, the occurrence of irregular grains of coarse aggregate cause...
Techno-Press, 2019
In this paper, the workability and static stability were evaluated using a proposed test method. Workability and static stability represent a key property of self-compacting concrete (SCC) in fresh state. A number of standardized test methods were developed to assess these properties. However, no accelerated test method reliably predicts both workability and static stability of SCC. In the present work, a modified K-slump test method was developed to evaluate workability and static stability of SCC. In order to take implicit mixture variations of SCC constituents that can affect fresh SCC properties, a central composite design was adopted to highlight the effect of gravel to sand ratio (G/S), gravel 3/8 to gravel 8/15 ratio (G1/G2), water to cement ratio (W/C), marble powder to cement ratio (MP/C) and superplasticizer content (SP) on workability measured with slump and flow time (T50) tests and static stability measured with sieve stability test (Pi), segregation test index (SSI), Penetration test (Pd) and the proposed K-slump test (Km). The obtained results show that G/S ratio close to 1 and G1/G2 ratio close to 60% can be considered as optimal values to achieve a good workability while ensuring a sufficient static stability of SCC. Acceptable relationships were obtained between Slump flow, Pi, Pd and Km. Results show that the proposed K-slump test allow to assess both workability and static stability of fresh SCC mixtures.
Properties of Self-Compacting Concrete with Different Sources of Coarse Aggregates
IOP conference series, 2019
Aggregate size and its source are crucial for concrete properties. This paper presents the evaluation of the properties of self-compacting concrete (SCC) which mixed with coarse aggregate from different sources. Coarse aggregate from three sources which are commonly available in Vientiane Capital, Mekong River (MK), Ngum River (NG) and Crushed Mountain Stone (MT) were used for this study. Six different mixed proportions with two maximum aggregate size 19mm and 12.5mm for each aggregate source were prepared. Ordinary Portland Cement Type I and Fly ash class C were used as binders. The replacement ratio of fly ash to cement was fixed at 20% and w/p ratio was 0.36. Sika Viscocrete-3180MR was used as water reducing admixture with 0.95% by weight of binders. The results show that, for the fresh concrete properties, the coarse aggregate with maximum size of 12.5mm from Mekong River is the most suitable aggregate comparing to other sources. For the hardened concrete with 28-day curing, the highest compressive strength is the mixed proportion MK12 for aggregate size 12.5mm. As seen, the coarse aggregate with 12.5mm of Mekong River is the most appropriate aggregate among three sources which has a flow-ability and higher compressive strength.
IRJET- Effect of Size of Coarse Aggregate on Self Compacting Concrete of M50 Grade
IRJET, 2020
Concrete is one of those crucial inventions which have transformed man's need of building long-lasting and reliable structures near and around him for numerous purposes. Today, its importance can be justified with the fact that concrete is the second most-consumed material in the world after water. Over time researchers have brought up new design methods, replacements in compositions, and numerous other innovative ideas to achieve better results in concrete. To achieve the required strength and durability of concrete, it requires proper and sufficient compaction while placing it. A requirement of skilled labor for compaction and improper compaction in congested reinforcement is another issue. Therefore to overcome these problems, this concept of SCC emerged in Japan in the 1980s and later spread across many other countries. SCC can be defined as fresh concrete that flows under its own weight and does not require external vibration to undergo compaction. The present investigation is aimed at studying the effects of the size of coarse aggregate on M50 grade of SCC. Using Nan Su's Mix design method different mix designs were prepared for 20mm, 16mm & 12.5mm aggregates separately. For checking fresh properties slump test & t50 tests were conducted. For hardened properties Compressive strength test, Flexural strength test and Split tensile test were conducted. It was found that with a decrease in the size of coarse aggregate in SCC, it yielded better fresh and hardened properties.
2018
Self Compacting Concrete (SCC) is a selfsettling concrete without any vibration. Its important property is flowing on its own weight, requiring no labor for its compaction. Usually the aggregate size used in SCC varies from 10mm to 12.5mm, to accomplish for its flow on itself. The maximum percentage of coarse aggregate used in the SCC is about 50 to 55 percent, so that the remaining amount is mortar matrix, which is responsible for flow property of SCC. Now the problem in SCC is to obtain the desired target strength by using the available concrete mix design procedure. It is proved that in Delhi metro railway project that SCC can be effectively used, better than ordinary, high strength and high performance concrete. In this article we are using coarse aggregate, of size 6/5 mm and make an attempt to check its rheological property (Flow property). The method is compared with standard results and its use in Industry is justified.
- Concrete can be considered as the most widely used in the construction industry. Concrete is a composite material made up of cement, sand, water and sometimes admixtures. Cement is the most active component and the use of large quantities of cement results in increasing CO2 emissions and as a consequence of the green house effect. On the other hand continuous use of natural aggregates causes environmental problems and it is also necessary to preserve the natural sources. The use of sustainable technologies such as supplementary materials is expected to positively affect the performance of concrete mixtures. Self-compacting concrete (SCC) is an innovative development of conventional concrete, which can be placed and compacted under its self weight with little or no vibration effort. This paper present the Mechanical and Durability properties of self compacting concrete using cementitious materials as a partial replacement of cement like Fly ash(15%), Silica fume(15%) and Metakaolin(5%) ; Artificial fine aggregate as natural fine aggregate having fineness modulus 2.7; Coarse aggregate of size 12mm and CONPLAST SP337 as Super-plasticizer. SCC containing different proportion of these mineral admixtures has been tested for slump flow, V-funnel, L-box, U-box and J-ring and found that the values are within the limits prescribed by EFNARC, 2002 method. The properties reported in this paper are the workability properties, Mechanical properties and Durability Properties. The Workability properties were investigated by Slump flow (filling ability), V-Funnel (filling ability) and L-Box test (passing ability). The Mechanical properties were tested for Compressive strength, Splitting Tensile strength and Flexural strength of 7 days, 28 days and 90 days were obtained. The Durability properties were tested for Water absorption and Acid tests. Key words: SELF COMPACTING CONCRETE, FLY ASH, SILICA FUME, METAKAOLIN, ARTIFICIAL FINE AGGREGATE, CONPLAST SP337.
Effect of water/cement ratio on the fresh and hardened properties of self-compacting concrete
Building and Environment, 2007
The use of self-compacting concrete (SCC) with its improving production techniques is increasing every day in concrete production. However, mix design methods and testing procedures are still developing. Mix design criterions are mostly focused on the type and mixture proportions of the constituents. Adjustment of the water/cement ratio and superplasticizer dosage is one of the main key properties in proportioning of SCC mixtures. In this study, five mixtures with different combinations of water/cement ratio and superplasticizer dosage levels were investigated. Several tests such as slump flow, V-funnel, L-box were carried out to determine optimum parameters for the self-compactibility of mixtures. Compressive strength development, modulus of elasticity and splitting tensile strength of mixtures were also studied.
A review paper on Self Compacting Concrete with Recycled Aggregates
Self Compacting Concrete (SCC) is an innovative concrete that does not require any vibration for compaction. The study was carried out by replacing various percentages (10%, 20%, 30%) of natural aggregates in SCC with recycled coarse aggregates and the properties of SCC were evaluated. A comparison of SCC with concrete compacted using conventional method was also included in the study. The additive used in SCC for the study was Fly ash. The mix designs arrived for an M-30 mix. To reduce the water-binder ratio and to get sufficient flowability for SCC a polycarboxylic based superplasticizer was used. Mix design for SCC was carried out as per 'European Guidelines for SCC' based on 'Nan Su et-al method' of mix design. Fresh properties including Slump flow test, T-500 test, V-funnel and L-box test were carried out for SCC. Hardened properties of concrete like Compressive Strength, Flexural Strength, split tensile Strength and Water absorption test were carried out for traditional concrete and SCC. By comparing the strength parameters of different mixes, it was observed that SCC is a good alternative of traditional concrete with and without using recycled aggregates.