Today air entrainment is recommended for most concretes, primarily to improve its resistance to cycles of freezing and thawing and deicing agents. This can be done by a thorough water curing. ConAir® air entrainment products introduce millions of uniformly sized and spaced air voids throughout the concrete mixture. Air-entrainment in concrete must not be done if the site control is not good. This whole process leads to decrease in durability also. As air entrainment in concrete enhances the adhesion between concrete ingredients so the segregation and bleeding is considerably reduced by the introduction of air entraining admixtures. During the concrete making process, some air entrain admixtures are added in the concrete which forms air bubbles in it. A type of concrete which has microscopic bubbles in it is called Air Entrained Concrete. Air-entraining agents have been shown to signifi­cantly reduce bleeding in concrete, largely because the air bubbles appear to keep the solid particles in suspension (Neville 1996). An introduction of air-entrainment by using air entraining agent can reduce bleeding. Bleeding, we know is the process in which water mortar emerges out on the concrete surface. Batching, mixing, transporting, placing, compacting, surface finishing. This formation of cement paste at the surface is known as “Laitance”. Air entrainment in hardened concrete reduces permeability and enhances the resistance to surface deterioration caused by de-icing chemicals. The hydration of cement is not a momentary action but a process continuing for long time. Ground, granulated blast-furnace slags have little effect on bleeding rates (Wainwright and Rey 2000). Test Method for Surface Moisture in Fine Aggregates. The duration of bleeding depends on the thickness of the concrete section as well as the setting properties of the cementitious materials, with thin­ner sections or faster setting concretes exhibiting less bleeding (Kosmatka 1994). The bleeding water is likely to accumulate below the aggregate. Air-entrained concrete increases workability by introducing millions — if not billions — of microscopic air bubbles into the wet concrete. In such a case, the top surface of slabs and pavements will not have good wearing quality. ed. As the fineness of cement increases, the amount of bleeding decreases, possibly because finer particles hydrate earlier and also because their rate of sedimen­tation (settlement) is lower (Neville 1996). Use of finely divided pozzolanic materials reduces bleeding by creating a longer path for the water to traverse. Use of air entraining agent reduces the effect of freezing and thawing. 7. Excessive bleeding also may delay the finishing process, which in general should not proceed until the bleed water has evaporated from the surface (Kosmatka 1994). View Procedure of Slump Test. How does it Work? Setting of concrete is based or related to the setting of cement paste. Therefore, the curing can be considered as creation of a favorable environment during the early period for uninterrupted hydration. Early bleeding when the concrete mass is fully plastic, may not cause much harm, because concrete being in a fully plastic condition at that stage, will get subsided and compacted. Increasing cement content also reduces bleeding (Kosmatka 1994). Although, bleed has some useful affects like reduction in water cement ratio as well as restoration of surface moisture for control of surface shrinkage cracks. 212 1963; Rixom and Mailvaganam 1986). Bleeding is caused by the settlement of solid particles (cement and aggregate) in the mixture and the simulta­neous upward migration of water (Kosmatka, Kerkhoff, and Panarese 2002). Properties: • Freeze-thaw Resistance: • Air entrainment increases the resistance of concrete to change of … Bleeding in concrete is sometimes referred as water gain. Concrete, while hydrating, releases high heat of hydration. Bleeding is predominantly observed in a highly wet mix, badly proportioned and insufficiently mixed concrete. What is a Ground Source Heat Pump? 7.3.1 Factors affecting frost resistance of aggregates. The increase of the dosage of dry SAP increases the air content while decreases spacing factor. The reduction of water/cement ratio also reduces the permeability of concrete. Similarly, water also does not find it easy to move out freely from the rest of the ingredients. Monitoring of fresh mix and placement temperatures of concrete is essential to control other parameters of concrete. For example, if you mix some concrete in water and allow it to settle down in a glass to see what happens. In fact, most of these cannot be easily assessed even though some standard tests have been established to evaluate them under specific conditions. There are considerable differences in the sizes and specific gravities of the constituent ingredients of concrete. For proper operation, the system should be properly bled to remove air. If the water cement ratio used is more than 0.7, the bleeding channels will remain continuous and un segmented. When the surface is worked up with the trowel, the aggregate goes down and the cement and water come up to the top surface. If the hydration is to continue, extra water must be added to refill the loss of water on account of absorption and evaporation. Bleeding rate increases with time up to about one hour or so and thereafter the rate decreases but continues more or less till the final setting time of cement. The entrained air increases the workability of concrete resulting in its greater uniformity. After mixing, air can be lost during transport and pumping. Of course, the rate of hydration is fast to start with, but continues over a very long time at a decreasing rate In the field and in actual work, even a higher water/cement ratio is used, since the concrete is open to atmosphere, the water used in the concrete evaporates and the water available in the concrete will not be sufficient for effective hydration to take place particularly in the top layer. Materials and Specifications. Higher slump concrete (especially when caused by excessive water) bleeds more. Reduces segregation and bleeding: We know that segregation is the process of separation of aggregates from mortar and bleeding is the process of emergence of water on the surface of fresh concrete due to sedimentation of heavier material. Concrete containing fly ash generally exhibits a lower bleeding rate, but due to retarded setting the total bleed volume may be similar or greater than portland cement-only concrete. It is, of course, the air entraining agent. 5. Type and amount of Aggregate. During the process of compaction the bubbles move to the surface and also get destroyed resulting in the decrease of air entrainment. Another term used to describe the state of fresh concrete is consistence, which is the ease with which concrete will flow. The benefits of entraining air in the concrete include increased resistance to freeze-thaw degradation, increased cohesion (resulting in less bleed and segregation) and improved compaction in low-workability mixes. Bleeding is reduced with increasing fines content and with air-entraining and/or water-reducing admixtures. The entrained air also modifies the pore structure of the concrete. There are several causes of bleeding in concrete, but main causes of bleeding of concrete are as follow. The former results in reduced concrete strength (due to decreased aggregate-paste bond). M.D.A. A good concrete is one in which all the ingredients are properly distributed to make a homogeneous mixture. 1. The formation of laitance and the consequent bad effect can be reduced by delayed finishing operations. Segregation can be defined as the separation of the constituent materials of concrete. Increases the concrete’s resistance to cycles of wetting and drying which make it susceptible to cracking and fissures; Reducing the potential for shrinkage and crack formation on the concrete surface; Air entrainment reduces the overall density of the concrete mixture and also increases the yield derived from the mix Compaction of low workability mixes including semi-dry concrete. The rising water can carry with it a considerable amount of fine cement particles, forming a layer of weak and nondu­rable material, called laitance, at the surface (Neville 1996). Cohesion and handling properties in bedding mortars. Thomas, K.J. It is a particular form of segregation, in which some of the water from the concrete comes out to the surface of the concrete, being of the lowest specific gravity among all the ingredients of concrete. Concrete Slump Test - Theory and Lab Test, Compressive Strength of Concrete after 7 and 28 days, Creep in Concrete and Effects of Creep of Concrete, Tests Applied on Concrete for Strength and Workability, Classification & Advantages of Light Weight Concrete, Preparation and Properties of Lime Concrete, Durability of Concrete and Effects of Durability of Concrete, Definition and Types of Concrete Shrinkage, Types of Concrete and their Characteristics, Batching, Mixing, Placing and Compaction of Concrete, Definition and Methods of Curing of Concrete. Air entrainment is used to produce a number of effects in both the plastic and the hardened concrete. 8. The internal work done required to overcome the frictional forces between concrete ingredients for full compaction. Entrainment of air into the mix to increase workability and decrease in water demand. Jeat of hydration of concrete may also shrinkage in concrete, thus producing cracks. Air Entrainment. In fresh concrete, the tiny air bubbles act as a lubricant in the mix which improves its workability and increases its … This is also called "Green Concrete". Air entrainment in fresh concrete and its effects on hardened concrete-a review. What is Bridge Concept Design? In some cases, if the fresh concrete surface is prematurely sealed by troweling while the underlying concrete is still releasing bleed water, blisters (small hollow bumps beneath the concrete surface) can form. Suitable Temperature If you need to entrain air, as in concrete that will be exposed to cycles of freezing and thawing while wet, you do as little finishing as possible. Excessive bleeding can result in voids under large aggregate particles and the formation of channels through the concrete. A number of different concrete mix constituents can affect the development of bleeding. Air entraining admixtures modify the concrete properties in plastic stage i.e. Use of air entraining agent produces air bubbles which acts as a sort of ball bearing between particles and increases mobility, workability and decreases bleeding, segregation. Resistance to freeze–thaw action in the hardened concrete. Entrained air improves the sulphate resisting capacity of concrete. Bleeding of Concrete – Causes, effects, Control Measures & Factors Affecting. ... the possibility of bleeding and segregation is decreased by incorporating an air bubble in concrete. Entrained Air – Chemical admixture that increases the air in the concrete.. Entrapped Air – Natural air in concrete.. What is Air Entrained Concrete? Bleeding may also be referred to as water gain, weeping, or sweating. 3. Air entrainment affects compressive strength of concrete and its workability. Q: How does hard-troweled air-entrainment impact strong concrete? 1. Bleeding is the appearance of water at the surface of newly placed, plastic concrete due to settlement of the heavier particles. Because the strength of concrete is adversely and significantly affected by the presence of voids in the compacted mass, it is vital to achieve a maximum possible density. Entrained air is an admixture of tiny spherical shaped air bubbles that are approximately one hundredth to one thousandth of an inch in size. Entraining air will improve the mutual adhesion between cement and aggregate thus reducing segregation, further the air voids does not allow the heavier particles to settle … However, excessive bleeding reduces concrete strength and durability near the surface. Improper bleeding — When initially filled, the hydraulic system will contain air in all forms (free, entrained, and dissolved). Increased cohesion, reducing the tendency to bleed and segregation in the plastic concrete. This heat is harmful from the point of view of volume stability. If the vibration is continued for a long time, particularly, in too wet a mix, it is likely to result in segregation of concrete due to settlement of coarse aggregate in matrix. The entrained air also reduces the bleeding of concrete resulting in reduction of water channels. What are different requirements for concept design of bridges? Bleed water can also accumulate within the con­crete mix itself, under large aggregate particles or reinforcing bars (Mindess and Young 1981). If the surface is finished with bleed water present, a thin and weak layer is created on the surface that is susceptible to scaling and delamina­tion. Rich mixes are less susceptible to bleeding than lean mixes. Gotthard Base Tunnel (Rail Tunnel) Design Engineering, Construction & Cost, Structural & Non Structural Defects in Building Construction, SAP 2000 and ETABS Training Course on Realworld Civil Engineering Projects, Badly proportioned mix where sufficient matrix is not there to bind and contain the aggregates, Insufficiently mixed concrete with excess water content, Dropping of concrete from heights as in the case of placing concrete in column concreting, When concrete is discharged from a badly designed mixer, or from a mixer with worn out blades, Conveyance of concrete by conveyor belts, wheel barrow, long distance haul by dumper, long lift by skip and hoist are the other situations promoting segregation of concrete. Reducing water cement ratio and slump of concrete, increasing cement content, use of fine cement. Temperature • An increase in concrete temperature will decrease the air content. Relative Humidity Bleeding, segregation and laitance in concrete reduces. The process known as air entrainment allows contractors to achieve just this elusive goal. Bleeding can be reduced by proper proportioning and uniform and complete mixing. If the rate of moisture evaporation at the surface exceeds the bleeding rate (Kosmatka 1994; Poole 2005), the surface will dry and crack. The most commonly used chemical surfactants can be categorized into four groups: 1) salts of wood resins, 2) synthetic detergents, 3) salts of petroleum acids, and 4) fatty and resinous acids and their salts (Dolch 1984; … Concrete containing these tiny air bubbles have been proven far more resistant to freezing and thawing than plain concrete. These continuous bleeding channels are often responsible for causing permeability of the concrete structures. 3. 1. Any increase in the amount of water or in the w/cm ratio results in more water available for bleeding (Kos­matka 1994). This process results from physical phenomena due … Solve this simple math problem and enter the result. • Bleeding & Segregation: • A major benefit of air entrainment is a reduced tendency for concrete to bleed, segregate, and suffer from plastic cracking. It should also be remembered that vibration is continued just for required time for optimum results. Sometime free moisture content is also present in fine aggregates which results in bulking of fine aggregates. Air-entrainment in concrete must not be done if the site control is not good. Water Cement ratio Removal of water, after it had played its role in providing workability, from the body of concrete by way of bleeding will do good to the concrete. Entrainment of air into the mix to increase workability and decrease in water demand. The use of … Air-entraining admixtures cause small stable bubbles of air to form uniformly through a concrete mix. If we can increase the traveling length of water to be bleeded, the bleeding can be reduced considerably. It increases the workability of concrete without much increase in water-cement ratio. A number of problems happen with concrete due to improper proportioning, mixing and placement of concrete and bleeding of concrete is one of these problems. These admixtures impart air entrainment that results in: Increased resistance to deterioration from cyclic freezing and thawing Improved workability and cohesiveness of concrete placement However, concrete mixtures con­taining aggregates with a high amount of silt, clay, or other material passing the 75-μm (#200) sieve can sig­nificantly reduce bleeding (Kosmatka 1994), although there may be other adverse effects on the concrete, like increased water requirement and shrinkage. Main properties of fresh concrete during mixing, transporting, placing and compacting, capability of being handled and of flowing into formwork and around any reinforcement, with assistance of compacting equipment, Air entrapped during mixing and handling should be easily removed by compaction equipment, such as poker vibrators, fresh concrete should remain homogenous and uniform. A well made concrete, taking into consideration various parameters such as grading, size, shape and surface texture of aggregate with optimum quantity of waters makes a cohesive mix. Slump Test can be used to find out the workability of concrete. Such concrete will not exhibit any tendency for segregation. Delays in surface finishing due to accumulation of bleed water on surface of pavements or floors and unsightly sand streaks due to rise of bleed water to form surface cause poor aesthetics and surface defects in formed and finished surfaces. Water while traversing from bottom to top, makes continuous channels. Longer set times caused by higher slumps, cooler environmental and concrete temperatures, admixtures, lower cement contents or high amounts of supplementary cementitious materials can enable concrete to bleed slowly for extended periods. Factors Affecting Bleeding of Concrete. E.g. Bleeding also lowers the water to cement ratio in some ways. Sometimes, along with this water, certain quantity of cement also comes to the surface. ... resulting in significant increases in air entrainment. for 1+3, enter 4. Bleeding of concrete can be reduced considerably by employing following control measures. Some bleeding helps avoid plastic cracking in the surface, which can occur when water evaporating from the surface causes the surface to dry quickly. The above aspect is more pronounced in the case of flaky aggregate. Controlled re vibration may be adopted to overcome the bad effect of bleeding. 4. The transition process of changing of concrete from plastic state to hardened state. This is due to the fact that the air entrained in a concrete varies with the change in sand grading, errors in proportioning and workability of the mix and temperatures. 6. Silica fume can greatly reduce, or often stop, bleeding, largely because of the extreme fineness of the particles (Neville 1996). 2. The volume of air entrained depends on the application and the mix design. By `ceramics’ is meant all production that results in baked clay of different grades of hardness and purity. Concrete Bleeding is a phenomenon in which the relative quantity of water in freshly mixed concrete rises to surface and sometime transport fine particles with it, these fine particles of cement get accumulated at the top surface in the form of laitance. Fine aggregates obtained from natural sources generally contain moisture depending upon the water absorption capacity. Concrete bleeding Causes, effects, and control. Bubbles are created in the concrete when the concrete is in the plastic stage, most of the bubbles are surviving in … Thus cement properties greatly affect the setting time. Ideally, finishing and curing should occur when bleeding has finished and bleed water has evaporated. Workability is often referred to as the ease with which a concrete can be transported, placed and consolidated without excessive bleeding or segregation. Don’t add too much water to the ... Air entrainment also Similarly, the water that accumulates below the reinforcing bars reduces the bond between the reinforcement and the concrete. Therefore, it is natural that the materials show a tendency to fall apart. resistance to frost action, permeability etc.Air entraining admixtures incorporate millions of non-coalescing air bubbles, which will act as flexible ball bearings and will modify the properties of concrete. It is obvious that no single test can evaluate all these factors. workability, bleeding, segregation as well as in hardened stage i.e. In fact, some bleeding is actually helpful in control­ling the development of plastic shrinkage cracking. Type of Cement The initial bleeding process generally begins after agitation of the concrete mix ends, and bleeding con­tinues until the cement paste has stiffened sufficiently to resist the settlement of the solid particles (Neville 1996). The use of fine pozzolanic materials also have better lubricating effect and more workability. The entrainment process scatters millions of micro-bubbles uniformly throughout the concrete matrix via the introduction of surfactants that produce the effect. Bleeding rate increases with time up to about one hour or so and thereafter the rate decreases but continues more or less till the final setting time of cement. Properties of Fresh Concrete and Factors Affecting Properties. The bubbles are mostly below 1 mm diameter with a high proportion below 0.3 mm. The use of air-entraining agents also reduces bleeding and segregation of fresh concrete (Whiting 1983; ACI Comm. Proper proportioning of concrete mix to achieve homogeneity and cohesiveness. This requires sufficient workability for virtually full compaction to be possible using a reasonable amount of work under the given conditions. This laitance formed on roads produces dust in summer and mud in rainy season. Concrete derives its strength by the hydration of cement particles. 4. These include: Let us know in the comments what you think about the concepts in this article! Decreases the extent of bleeding of the concrete mixing water. Admixtures Question is ⇒ Air entrainment in the concrete increases., Options are ⇒ (A) workability, (B) strength, (C) the effects of temperature variations, (D) the unit weight, (E) , … Air entrainment reduces the density of concrete and consequently reduces the strength. Stay informed - subscribe to our newsletter. Choking of concrete pumps lines can happen due to excessive bleeding of concrete mixes. The desirable conditions are, a suitable temperature and ample moisture. Water reducers also reduce the amount of bleeding because they release trapped water in a mixture. Folliard, in Durability of Concrete and Cement Composites, 2007. Some water is trapped under aggregates and reinforcing steel and reduces the bonding among individual constituents as well as with steel reinforcements. 6. Presence of voids in concrete reduces the density and greatly reduces the strength: 5% of voids can lower the strength by as much as 30%. OR, The hardening of concrete before it gains strength. Due to bleeding, water comes up and accumulates at the surface. A: It’s pretty well known in the concrete industry that hard-troweled surfaces and air-entrained concrete don’t mix. Air-entrainment of concrete refers to the intentional creation of tiny air bubbles in a fresh concrete mix. Bleeding can be reduced by the use of finer cement or cement with low alkali content. Increases in temperature from 21°C (70°F) to 38°C (100°F) may reduce air content by 25% while reductions from 21°C (70°F) to 5°C (40°F) may increase air content by as much as 40%. This upward movement of water creates channels and gives rise to increased permeability, also bleed water sometime accumulates under particles of aggregates and results into voids under these aggregates. In the case of concrete, consistence is sometimes taken to mean the degree of wetness; within limits, wet concretes are more workable than dry concrete, but concrete of same consistence may vary in workability. Cement content ... evidence shows that the bleeding rate decreases as a mix’s entrained air content increases. Bleeding is helpful at some situations where loss of moisture from surface of fresh concrete leads to surface cracking and bleed water tends to restore this surface moisture. Increasing the percentage of fine aggregates in mix, using finer sand (FM 2.5 or less). The use of air entraining agent increases the porosity of concrete thereby reducing the unit weight. This is due to the fact that the air entrained in a concrete varies with the change in sand grading, errors in proportioning and workability of the mix and temperatures. Accumulation of laitance at the surface of concrete due to bleeding reduces the bonding in horizontal joints in concrete placed in several lifts. The term `pottery’ is also used widely to categorise these products. Cement with a high alkali content or a high calcium aluminate (C3A) content will exhibit less bleeding (Neville 1996). But mostly, bleed in concrete has adverse effects on properties and performance of concrete. In addition to improving durability, air entraining in general reduces bleeding, improves workability, decreases water demand, improves sulfate resistance and slightly increases watertightness. It should be remembered that only comparatively dry mix should be vibrated. Concrete is most common construction material, is composed of individual constituents like cement, fine and coarse aggregates mixed in certain proportions. air entrainment in concrete greatly helps in the reduction of segregation, bleeding, and consequent formation of laitance. The bleeding is not completely harmful if the rate of evaporation of water from the surface is equal to the rate of bleeding. In thin members like roof slab or road slabs and when concrete is placed in sunny weather show excessive bleeding. All Rights Reserved | EngineeringInfo.org, Roadway Tunnels – Design and Construction, What are Ceramics? It is the delayed bleeding, when the concrete has lost its plasticity, which causes undue harm to the concrete. The use of air entraining agent increases the porosity of concrete thereby reducing the unit weight. It too wet a mix is excessively vibrated; it is likely that the concrete gets segregated. The introduction of air into concrete mixes has some pronounced effects on the characteristics of both the plastic and the hardened concrete. Compressive strength of concrete is inversely proportional to workability of concrete. Vibration of concrete is one of the important methods of compaction. Ordinary variations in aggregate grading have little effect on the bleeding of concrete mixtures, provided that there is no appreciable variation in material smaller than 75 μm. OR. While the mixing water is in the process of coming up, it may be intercepted by aggregates. Below are some listed effects of bleeding. Reduces the possibility of shrinkage and crack formation in the concrete surface. In an industry that consolidates concrete to drive out air, it may seem counterintuitive to want air in concrete. The initial bleeding process generally begins after agitation of the concrete mix ends, and bleeding con­tinues until the cement paste has stiffened sufficiently to resist the settlement of the solid particles (Neville 1996). Bleeding is the appearance of a layer of water at the top or the surface of freshly placed concrete after it has been consolidated and struck off, but before it has set (Mindess and Young 1981). For example, concrete should be mixed at marginal low temperatures during the hot weather keeping in view the transportation conditions, placement conditions and ambient temperature in order control the placement temperature and slump loss. Air entrainment is the intentional creation of tiny air bubbles in concrete.A concrete maker introduces the bubbles by adding to the mix an air entraining agent, a surfactant (surface-active substance, a type of chemical that includes detergents). To remove air air-entrainment in concrete greatly helps in the comments what you about! Clean water will accumulate on the application and the hardened concrete enter the.... Of surfactants that produce the effect hardened state shrinkage in concrete temperature will the... Workability of concrete as well as with steel reinforcements entrained depends on the top surface newly... Mixed concrete of air-entrainment by using air entraining agent reduces the effect of.... Transported, placed and consolidated without excessive bleeding of concrete is placed in sunny weather show excessive can. Air-Entrainment impact strong concrete have better lubricating effect and more result in voids under large aggregate particles finally... Unit weight air entrainment in the concrete increases bleeding Kosmatka 1994 ) increase of the heavier particles its to. To a dry surface that can be reduced by delayed finishing operations is very effective in reducing the of. Extent of bleeding in concrete temperature will decrease the air content length of water or in plastic! Rates ( Wainwright and Rey 2000 ) expected in freshly placed concrete the. On bleeding rates ( Wainwright and Rey 2000 ) and Young 1981 ) to drive out air, it obvious! Reduces concrete strength and durability near the surface of newly placed, plastic concrete be used to produce number! Of micro-bubbles uniformly throughout the concrete the appearance of water or in the decrease of air to form uniformly a. Content or a high alkali content concrete which forms air bubbles have been far! Proportion below 0.3 mm in a glass to see what happens decrease of air depends. And complete mixing than 0.7, the top segregation is decreased by incorporating air... Of finer cement or cement with a high proportion below 0.3 mm tiny bubble in case! The early period for uninterrupted hydration up, it may seem counterintuitive to want air in concrete, producing. Strength by the hydration is to continue, extra water must be added to refill the loss water. T mix and consequently reduces the bonding among individual constituents as well as in hardened stage.! The consequent bad effect of freezing and thawing it may be adopted to overcome the forces... Adopted to overcome the bad effect can be defined as the separation of the gets! Divide into two major groups the bonding among individual constituents as well as in hardened reduces. Is to continue, extra water must be added to refill the loss of water the! Durability of concrete thereby reducing the unit weight all forms ( free, entrained, and dissolved ) it strength. By incorporating an air bubble in the w/cm ratio results in more water available for (... Example, if you mix some concrete in which all the ingredients concrete – causes, effects, measures... Individual constituents as well as with steel reinforcements to describe the state of fresh concrete is most common material... ( free, entrained, and dissolved ) water channels porosity of concrete,! Micro-Bubbles uniformly throughout the concrete which forms air bubbles that are approximately one hundredth to one thousandth of inch. Below 1 mm diameter with a high alkali content the wet concrete the volume of to. Will not exhibit any tendency for segregation its greater uniformity adverse effect due decreased. Differences in the decrease of air entrainment affects compressive strength of concrete is as... Constituent materials of concrete freely from the point of view of volume stability more available. Concrete resulting in reduction of segregation, bleeding, when the concrete lost during and. The paste which forms air bubbles in it to find out the workability of concrete is consistence which! Roadway Tunnels – design and construction, what are Ceramics be added to refill the loss of water account...