Self Compacting Concrete

Abstract:

Making concrete structures without vibration have been done in the past but are generally of lower strength and were of un-consistent quality. Recognizing the lack of uniformity and complete compaction of concrete by vibration, researchers at the University of Tokyo, Japan, started in late 1980’s to develop self compacting concrete (SCC). SCC is a highly flowable, yet stable concrete that can spread readily into place and fill the formwork without any vibration even  when  access  is  hindered  by  narrow  gaps  between  reinforcement  bars  and  without undergoing any significant segregation.

SCC is recognized by two of its primary properties: Ability to flow or deform under its own weight  and the ability to remain  homogeneous  while doing  so.  Flowability  is achieved by utilizing high range water reducing (HRWR) admixtures and segregation resistance is ensured by introducing a chemical viscosity modifying admixture (VMA) or increasing the amount of fines in  the  concrete.  Increased  fines  contents  can  be  achieved  by  increasing  the  content  of cementitious materials or by adding mineral fines. A well distributed aggregate grading helps achieve SCC at reduced cementitious materials content and/or reduced admixture dosage. Self- compacting concrete development must ensure a good balance between deformability and stability. Compactibility of SCC is greatly affected by the characteristics of materials and the mix proportions. As there is no standard method for SCC mix design therefore it becomes necessary to evolve a procedure for mix design of SCC. Another problem regarding SCC is that the tests carried out for ordinary concrete are not applicable for SCC because of its high fluidity, therefore separate testing should be done for testing the properties of  SCC. The paper presents an experimental procedure for the design of self compacting concrete mixes. The test results for characteristics of SCC such as slump flow, J-ring, V-funnel and L-Box are also presented.

1. Introduction

1.1.      Overview

For several years beginning in 1983, the problem of the durability of concrete structures was a major topic of interest around the world, especially in Japan. One of the main problems in achieving the durable concrete was the lack of proper compaction. Proper compaction requires skilled workers, however, the gradual reduction in the number of skilled workers around the world led to a similar reduction in the quality of construction work. One solution for the achievement  of durable  concrete  structures  independent  of the quality  of the construction work is the employment  of self-compacting  concrete,  which can be compacted  into every corner of a formwork, purely by means of its own weight and without the need for vibrating compaction [1]. The highly flowable nature of SCC is due to very careful mix proportioning, usually replacing much of the coarse aggregate with fines and cement, and adding chemical admixtures. It depends on the sensitive balance between creating more deformability while ensuring good stability, as well as maintaining low risk of blockage [2]. Therefore, the main property that differentiates SCC from OPC is its high workability in attaining the specified hardened properties without compaction.

1.2.      Composition

A typical composition of Self-compacting concrete is shown in Figure 1.Self-compacting concrete consists of the same components as conventionally vibrated normal concrete, which are cement, aggregates, water, additives and admixtures. However, the high amount of super- plasticizer for reduction of the liquid limit and for better workability, the high powder content as “lubricant” for the coarse aggregates, as well as the use of viscosity-agents to increase the viscosity of the concrete have to be taken into account [3]. In principle, the properties of the fresh and hardened SCC, which depend on the mix design, should not be different from OPC except consistency. Figure 2 shows the basic principles for the production of SCC.

Figure 1: Schematic Composition of SCC

Figure 2: Basic principles for the production of Self-Compacting Concrete

1.3.     Mechanism of SCC

Two important properties specific to SCC in its plastic state are its flowability and stability. The high flowability is attained by using high-range-water-reducing (HRWR) admixtures whereas stability of the plastic concrete mixture is attained by increasing the total quantity of fines in the concrete by increasing the content of cementitious material and/or by using viscosity modifying agent (VMA). Continuously graded aggregates helps in achieving SCC at reduced cementitious materials. SCC mixtures typically have a higher paste volume, less coarse aggregate and higher sand-coarse aggregate ratio than typical concrete mixtures.

SCC mixtures can be designed to provide the required hardened concrete properties for an application, similar to regular concrete. If the SCC mixture is designed to have higher paste content or fines compared to conventional concrete, an increase in shrinkage may occur [4].
Read More click below

2. Literature Review

2.1.     M S Shetty, Concrete technology, theory and practice

Several European countries recognized the significance and potentials of SCC developed in Japan. During 1989, they founded European federation of natural trade associations representing producers and applicators of specialist building products (EFNARC). The utilization of self- compacting concrete started growing rapidly. EFNARC, making use of broad practical experiences of all members of European federation with SCC, has drawn up specification and guidelines to provide a framework for design and use of high quality SCC, during 2001.

There are three ways in which SCC can be made

I.      Powder Type

II.      VMA Type

III.      Combined type

In powder type SCC is made by increasing the powder content. In VMA type it is made by using viscosity modifying admixture. In combined type it is made by increasing powder content and using VMA. The above three methods are made depending upon the structural conditions, constructional conditions, available material and restrictions in concrete production plant.

The main characteristics of SCC are the properties in the fresh state. The mix design is focused on the ability to flow under its own weight without vibration, the ability to flow through heavily congested reinforcement under its own weight, and the ability to retain homogeneity without segregation.

2.2. Timo Wustholz, Fresh properties of SCC, Otto-Graf-Journal Vol. 14, 2003

SCC owns over three key characteristics which are filling ability, passing ability and segregation resistance. These characteristics were made possible by the development of highly effective water reducing agents (super-plasticizers), those usually based on poly-carboxylate ethers. The mixture composition of SCC deviates from conventional concrete. The powder contents of SCC are normally lying above those of conventional concrete.

Because of its special fluidity, SCC requires modified fresh concrete testing methods compared with conventional concrete. The difficulty consists of the fact, that SCC responds very sensible to deviations of mixture proportions. Already slightest deviations can lead to a concrete that does not obtain one or more of these key characteristics. This is usually connected with substantial lack of the finished construction unit, which lower not least the durability drastically and make in the worst case a construction useless.

2.3.     M.K. Hurd, Self Compacting Concrete, Publication #C02A044 2002Hanley-Wood, LLC

A specific mix design must be based on the intended application, suited to anticipated congestion of reinforcement or complexity of the form. Typically there will be less coarse aggregate and a proportionally larger amount of fines, including Portland cement, fly ash, ground slag, and stone powder. Broadly speaking, the fresh SCC must be able to flow into all the spaces within the formwork under its own weight. It also must flow through narrow openings such as the spaces between reinforcing bars, a constraint that may limit the maximum aggregate size. While maintaining this flow, it also must resist segregation. Meeting all of these demands results in mix proportions that differ from conventional concrete, as shown in table 1.

Table 1: Volume comparison of materials in typical SCC and conventional concretes

Material	Normal Concrete, by Volume	SCC, by volume
Admixtures	Trace	0.01%
Water	18%	20%
Coarse Aggregate	46%	28%
Sand	24%	34%
Fines, including Cement	12%	18%

3.      Latest Research on SCC

 Latest research on self compacting concrete is done by Pedro Silva, Jorge de Brito, and Joao Costa, under the heading of Viability of Two New Mixture Design Methodologies for Self- Consolidating Concrete, title No. 108 M-61 published in ACI Materials Journal/November- December 2011.

This paper presented the results from an experimental study of the technical viability of two mixture designs for self-consolidating concrete (SCC) proposed by two Portuguese researchers (Ferreira (2001), Nepomuceno (2005) ). The objective was to find the best method to provide the required characteristics of SCC in fresh and hardened states without having to experiment with a large number of mixtures. Methodology includes the preparation of five SCC mixtures, each with a volume of 25 L (6.61 gal.) using a forced mixer with a vertical axis for each of three compressive strength targets: 40, 55, and 70 MPa (5.80, 7.98, and 10.15 ksi). The mixtures’ fresh state properties of fluidity, segregation resistance ability, and bleeding and blockage  tendency,  and  their  hardened  state  property  of  compressive  strength  were  also compared by performing slump-flow, V-funnel, L-box, box, and compressive strength.

The conclusions of the above paper were that SCCs produced using the Nepomuceno method is better in terms of self-compactibility than those produced using the Ferreira method. However

from a practical point of view, the Ferreira method is simpler and makes the influence of changes in component content on concrete behavior easier to understand. The writer further added that the Nepomuceno method could be improved if the Vp/Vs ratio (volume ratio between the total powder content, cement and mineral additions, and fine aggregates in the mixture) described in the beginning of this paper were adjusted to a behavior target. In this study, the Vp/Vs ratio was considered to be constant and equal to 70% [5].

4.   Specific Uses of SCC

Self-compacting concrete (SCC) is an innovative concrete that does not requires any vibration for placing and full compaction. It has the ability to flow under its own weight. The hardened concrete is dense, homogeneous and has almost the same mechanical properties and durability as traditional vibrated concrete.

SCC has many advantages over normal concrete. Some of them are listed below.

I.      From the contractors point of view costly labor operations are avoided improving the efficiency of the building site.

II.      The concrete workers avoid poker vibration which is a huge benefit for their working environment.

III.      When  vibration  is  omitted  from  casting  operations  the  workers  experience  a  less laborious work with significantly less noise and vibration exposure.

IV.      SCC is believed to increase the durability relatively to vibrated concrete (this is due to the lack of damage to the internal structure, which is normally associated with vibration) [6]

V.      SCC is favorably suitable especially in highly reinforced concrete members like bridge decks or abutments, tunnel linings or tubing segments, where it is difficult to vibrate the concrete, or even for normal engineering structures.

5.     Constituents of SCC

5.1.     Cement

Ordinary Portland cement, 43 or 53 grade can be used for making SCC.

5.2.     Aggregates

Among the various properties of aggregate, the important ones for SCC are the shape, size and gradation. The maximum size of aggregate is generally limited to 20 mm (3/4”). Aggregate of size 10 to 12mm is normally used for structures having congested reinforcement. It is observed from the studies that self-compactibility is achievable at lower cement (or fines) content when rounded aggregates are used, as compared to angular aggregates. Rounded aggregates would provide a better flowability and less blocking potential for a given water-to-powder ratio, compared  to  angular  and  semi-rounded  aggregates.  Moreover,  the  presence  of  flaky  and elongated particles may give rise to blocking problems in confined areas. The moisture content or absorption characteristics must be closely monitored as quality of SCC is very sensitive to such changes. Particles smaller than 0.125 mm i.e. 125 micron size are considered as fines which contribute to the powder content.

5.3.     Mixing Water

Water quality must be established on the same line as that for using reinforced concrete or pre- stressed concrete.

5.4.     Chemical Admixtures

Super-plasticizers are an essential component of SCC to provide necessary workability. The new generation super-plasticizers termed poly-carboxylate ethers (PCE) is very useful for SCC. Other

types may be used if necessary, such as Viscosity Modifying Agents (VMA) for stability, air entraining agents (AEA) to improve freeze-thaw resistance, and retarders for Control of Setting.

6. Mix design

SCC mixes must meet three key properties:

1. Ability to flow into and completely fill intricate and complex forms under its own weight.

2. Ability to pass through and bond to congested reinforcement under its own weight.

3. High resistance to aggregate segregation [7].

Also Self-compactibility can be largely affected by the characteristics of materials and the mix proportion. Therefore a rational mix-design method for self-compacting concrete using a variety of  materials  is  necessary.  Okamura  and  Ozawa  have  proposed  a  simple  mix-proportioning system assuming general supply from ready-mixed concrete plants [1]. The procedure is as followed.

6.1.     Volume of Coarse aggregate

Coarse aggregate volume is defined by bulk density. Generally coarse aggregate content is limited to 50% of solid volume [1]. Optimum coarse aggregate content depends on the following parameters.

•     The lower the maximum aggregate size, the higher the proportion.

•     The rounded aggregate can be used at higher percentage than angular aggregates.

6.2.     Volume of Fine aggregate

Sand content is defined by bulk density. The optimum volume content of sand in the mortar varies between 40-50% depending on paste properties [8]. However it is limited to 40% of volume of mortar [1].

6.3.     Design of paste composition

Initially the water/powder ratio for zero flow (bp) is determined in the paste, with chosen proportion of cement and additions. Flow cone tests with water/powder ratios by volume should be performed with the selected powder composition.

6.4. Determination of Optimum Volumetric Water/powder ratio and Super-plasticizer dosage in mortar

Tests with flow cone and V-Funnel for mortar are performed at varying water/powder ratios in the range of (0.8 bp to 0.9 bp) and dosages of super-plasticizer. The super-plasticizer is used to balance the rheology of the paste. The volume content of sand in the mortar remains the same as determined above.

 The target values are slump flow of 24 to 26 cm and V-funnel time of 7 to 11 seconds. If at target slump flow, the V-funnel time is less than 7 seconds, then decrease the water/powder ratio. If slump  flow  is  greater  than  26  cm  and  V-funnel  time  is  in  excess  of  11  seconds,  then water/powder ratio should be increased. If these criteria cannot be fulfilled, then the particular combination of materials is inadequate. One solution is to change the type of super-plasticizer. Another alternative is a new additive, and as a last resort is to change the cement [8]. The method of mix design is summarized in the Figure 3 given below.

Figure 3: Method of Mix design of SCC

Modifications to the above approach have been proposed by Edamatsu et al [9]. In the Edamatsu method, the limiting coarse aggregate volume ratio is kept at 0.5. The fine aggregate content, in this case, is then fixed using V-funnel test with standardized coarse aggregate (glass beads). Water-to-powder ratio and super-plasticizer dosage are determined from mortar flow and funnel tests.

The guidelines recommended by EFNARC [10] are also based on Okamura’s method. The difference is that instead of fixing the coarse aggregate limit at 0.5, a higher amount is permitted in the case of rounded aggregate (up to 0.6). The proportion of sand in the mortar is varied between 40 and 50 percent, and water-to-powder ratio and super-plasticizer dosage are determined through mortar slump flow and V-funnel tests. A comparison of the three methods discussed in this section is presented in Table 2.

Table 2: Empirical mixture portioning methods for SCC

Proposed by	Maximum      CA volume ratio	Maximum proportion        of sand   in    mortar (%)	Paste composition (w/p ratio)	Remarks
Okamura        and Ozawa	0.5	40 (empirical)	mortar  flow  and V-funnel tests	Originally developed   using moderate heat
Edamatsu et al	0.5	Determined     by V-funnel        test using standardized coarse aggregate	mortar  flow  and V-funnel tests	Enables determination  of stress transferability  of mortar
EFNARC	0.5-0.6	40-50% (empirical)	Mortar  flow  and V-funnel tests	Allows        more freedom   in coarse aggregate content

It can be inferred from Table 2 that the Edamatsu method provides a more scientific basis for fixing the mortar content of SCC, once the coarse aggregate content is decided. The method used by EFNARC, on the other hand, allows for including more coarse aggregate when rounded particles (as opposed to crushed particles) are used

7.      Comparison

In the mix proportioning of conventional concrete, the water-cement ratio is fixed at first from the viewpoint of obtaining the required strength where as in self-compacting concrete the water powder ratio has to be decided by taking into account the self-compactibility because self- compactibility is very sensitive to this ratio. In most cases, the required strength does not govern

the water cement ratio because the water-powder ratio is small enough for obtaining the required strength. The mix proportioning of self-compacting concrete is shown and compared with those of normal concrete and roller compacted concrete for dams (RCD) in Figure 4.

Figure 4: Comparison of mix proportioning of SCC with other types of conventional concrete [1]

SCC  generally  costs  a  few  more  dollars  per  cubic  yard  than  a  conventional  6-inch-slump concrete, however, the in-place cost of the concrete actually will decrease because of factors such as:

•     Reduced construction time

•     Reduced manpower for placing and compacting

•     Lower equipment costs and less noise since vibrators are not required

•     Ability to fill complex forms and members with congested reinforcement

•     Elimination  of  rubbing  and  patching  ordinarily  required  to  fill  defects  in  poorly consolidated surfaces

However, on the other side, some SCC mixes may gain strength more slowly because of higher proportions of fly ash, silica fume, or ground slag [11].

The  major  difference  between  self-compacting  and  conventionally-vibrated  concrete  is  the higher flowability of SCC, and consequently a higher proportion of fine materials. Given this difference, the available knowledge of concrete properties would suggest the differences in performance between these two concretes as shown in column 2 of Table 3. However, the reality could be sometimes different, as shown in the last column of this table.

Table 3: Differences in performance of SCC and normally-vibrated concrete

Property of SCC	Expectation	Reality
Variation in strength across depth of structure	Can   take   place    for SCC	No difference (between SCC and vibrated concrete)
Creep and drying shrinkage	Higher for SCC	No significant difference
Early age shrinkage and cracking	Higher for SCC	Higher for SCC
Strength and elastic modulus	No  difference  for same  grade  of concrete	No difference
Durability	Better for SCC	Better for SCC

8.      Quality control

Self- Compacting Concrete is characterized by filling ability, passing ability and resistance to segregation. Many methods have been developed to characterize the properties of SCC. No single method has been found until date, which characterizes all the relevant workability aspects, and hence, each mix must be tested by more than one test method for the different workability parameters.

8.1.     Filling ability

Filling ability reflects the deformability of SCC, i.e. the ability of fresh concrete to change its shape under its own weight [12]. Deformability includes two aspects:

8.1.1. Deformation capacity

It is the maximum ability to deform, that is, how far concrete can flow.

8.1.2. Deformation velocity

It refers to the time taken for the concrete to finish flowing, that is, how fast concrete can flow. A concrete with high deformation capacity and very low deformation velocity tended to be very viscous and would take long time to fill the formwork and vice versa [13].

8.2.     Passing ability

It determines how well the mix can flow through confined and constricted spaces and narrow openings, which makes it more useful in densely reinforced structures such as bridge decks, abutments etc. It depends on the risk of blocking which results from the interaction between constituent materials and obstacles.

8.3.     Segregation resistance

It is also known as ‘stability’. Since SCC is composed of materials of different sizes and specific gravities, it is susceptible to segregation. Segregation includes that between water and solid or between paste and aggregate or between mortar and coarse aggregate in both stationary and flowing states [13].

The above three key properties are to some extent related and inter-dependent.

A change in one property will result in a change in one or both of the others. Both poor filling ability and segregation can cause insufficient passing ability, i.e. blocking. Risks of segregation increase as filling ability increases.

SCC is actually a trade-off between filling ability and segregation resistance as shown in Figure

5.

Figure 5: Schematic ways to achieve SCC

9.      Fresh properties of SCC

The fresh properties of SCC are influenced by the variation in the fineness and moisture content of the aggregates, different batches of super-plasticizer or cement and changes in the environmental conditions such as temperature and humidity etc.

To ensure a sound quality of self-compacting concrete, a series tests should be carried out, test methods of the SCC concrete are listed in table 4.

Table 4: Test Methods for SCC Concrete

Character	Field Test	Measuring Unit	Range of Values
			Minimum	Maximum
Flowability	Slump Flow	mm	650	800
	T50 slump flow	Sec	2(3)	5(7)
	V-funnel	Sec	6	12
	Orimet	Sec	0	5
Passing ability	J-ring	mm	0	10
Segregation resistance	GTM-Test	%	0	15
	V-funnel at T5min	sec	0	+3

9.1.     Filling ability tests

Two aspects of SCC, deformation capacity and deformation velocity, are evaluated by filling ability tests, which include the slump flow test, V-funnel and the Orimet test.

9.1.1. Slump Flow test

The slump flow test is used to calculate the horizontal free flow of SCC in the absence of obstructions. On lifting the slump cone, filled with concrete, the concrete flows. The average diameter of the concrete circle is a measure for the filling ability of the concrete. The time T50cm is a secondary indication of flow. It measures the time taken in seconds from the instant the cone is lifted to the instant when horizontal flow reaches diameter of 500mm [14]. The schematic diagram of slump flow test is shown in Figure 6.

Figure 6: Schematic Diagram of Slump Flow Test

9.1.2. V- Funnel

The V- Funnel consists in a V-shaped container with an opening at the bottom (Fig.7). After filling, the bottom cover is opened and the time of discharge of the concrete through the opening is measured. The funnel flow time is an index of the deformation capacity and of the viscosity of the mixture. Because these two properties are correlated, the viscosity can be evaluated in relative terms only under the condition that the slump flow value remains constant. In such a case, a longer funnel flow time represents a higher viscosity of the mixture and it directly relates to a better resistance to segregation. According to Khayat and Manai, a funnel test flow time less than 6s is recommended for a concrete to qualify for an SCC [15].

Figure 7: V-Funnel Test

9.2.     Passing ability tests

Among the apparatus designed to measure the passing ability, the L-box test and J-ring test, in various dimensions and shapes, are most commonly used.

9.2.1. L-Box test

L-box test is used to assess the passing ability of SCC to flow through tight openings including spaces between reinforcing bars and other obstructions without segregation or blocking [16]. L- box has arrangement and the dimensions as shown in Figure 8. L-boxes of different sizes with different reinforcing bars and gaps can be use [16]. However, Investigations shows that the L- box is more sensitive to blocking and that it is more difficult for concrete to pass three bars than the two bars [17]. The vertical section of the L-Box is filled with concrete, and then the gate

lifted to let the concrete flow into the horizontal section. The height of the concrete at the end of the horizontal section is expressed as a proportion of that remaining in the vertical section (H2/H1). This is an indication of passing ability. The specified requisite is the ratio between the heights of the concrete at each end or blocking ratio to be ≥ 0.8.

Figure 3: L-Box Test

9.3.     Segregation tests 

Common  tests  used  for  checking  the  resistance  to  segregation  are  settlement  column  test, penetration test and sieve stability test.

9.3.1. Sieve Stability Test

It is also known as GTM screen stability test. The potential for segregation can be calculated by a simple sieve stability test, which measures the amount of laitance passing through a 5 mm sieve after a standard period, which is called sieve segregation or segregation index. The more mortar passing through the sieve, the higher segregation index, which indicates the higher risks of segregation in concrete after placing.

10.   Durability

Durability is a general analysis of the service life and the performance of concrete in an expose environment. Durability is greatly related to the resistance of the cover layer to transport mechanisms such as permeation, absorption and diffusion of gas and liquid. Thus oxygen permeability, water sorptivity and chloride conductivity have often been defined as three durability indexes due to the simple and inexpensive test methods [18].

The rate of water uptake by a porous material is defined as sorptivity. It has been considered as an important criterion to assess the durability of concrete. Experiments show that the  Sorptivity  of  SCC  was  only  30~40%  of  those  of  NVC  with  the  same  strength.[19] Diffusion  is  the  water  movement  driven  by  a  concentration  gradient  in  long  term exposure. Experimental results show that the diffusivity of SCC with viscosity modifying agents (VMA) is higher than normal concrete. [19]

It is also observed that the overall porosity of SCC was lower than that of NVC of equivalent strength because of the higher powder content, lower W/P ratio and improved microstructure [19]

11.   Challenges

•     Production of SCC requires more experience and care than the conventional vibrated concrete. The plant personnel would need training and experience to successfully produce and handle SCC. In the beginning, it may be necessary to carry out more tests than usual to learn how to handle SCC and gain the experience.

•     Most common concrete mixers can be used for producing SCC. However, the mixing time  may  be  longer  than  that  for  the  conventional  vibrated  concrete.  SCC  is  more sensitive to the total water content in the mix. It is necessary to take into account the

moisture/water content in the aggregates and the admixtures before adding the remaining water in the mix. The mixer must be clean and moist, and contains no free water.

•     Admixtures for the SCC may be added at the plant or at the site. There is cost benefit in adding the admixtures at the site. Conventional ready-mix concrete can be bought at a lower cost than the cost of SCC bought from a ready-mix supplier.[20]

12.   Applications

SCC technology originated in Japan in the early 1980s, arising out of durability concerns due to poor compaction on the job site. Use of SCC quickly became widespread in Japan, especially since the government implemented a plan to use SCC for 50% of all concrete jobs by 2003. It then spread to Europe in the 1990’s after invention of poly-carboxylate super-plasticizers.

In the UK, The Concrete Society has issued official measures to expand the use of SCC as a means of replacing vibratory compaction. In the US and Canada, SCC technology is available mostly  in  the  form  of  proprietary  concrete  mixes  from  ready-mix  producer  subsidiaries  of cement manufacturers such as Lafarge and Lehigh. It is also available as specialized admixtures combining super-plasticizer and viscosity modifiers [21].

In Pakistan, this technology is just introduced to contractors and pre-cast industrialists. A lot of research work is done by Prof. Dr. Rizwan (Professor of NUST) in this field. Also some remarkable contributions are made by Mr. Husnain Ahmad (Director NAB, Islamabad), Shazim Ali Memon (Lecturer NUST), Muhammad Ali Sheikh ( Lecturer MCE, NUST).

13.   Conclusions

1)  In  spite  of  its  short  history,  self  compacting  concrete  has  confirmed  itself  as  a revolutionary step forward in concrete technology.

2) It can be shown by cost analysis, that SCC in precast concrete plants can be more economically  produced  than  conventional  concretes,  in  spite  of  the  slightly  higher material price.

3)  SCC is favorably suitable especially in highly reinforced concrete members like bridge decks or abutments, tunnel linings or tubing segments, where it is difficult to vibrate the concrete, or even for normal engineering structures.

4)  The improved construction practice and performance, combined with the health and safety benefits, make SCC a very attractive solution for both precast concrete and civil engineering construction. Based on these facts it can be concluded that SCC will have a bright future.