Que5.14. Explain in detail the accoutrements which are needed to make ferro cement concrete.
Answer Following are the accoutrements needed for making ferro cement
1. Cement Mortar Mix i. Its factors are Portland cement, fine summations, water, and cocktails. ii. Material should satisfy all needful norms analogous to corroborated concrete. ii. Complements similar as superplasticizers, silica smothers, and fly ash can also be used.
2. Cadaverous sword To from the shell of the structures, sword is frequently used in ferrocement in the form of welded cables or a simple slur of sword cables, rods, or beaches. ii. Mesh layers are attached around this shell sword. The sword also acts as a spacer, leading to savings is the mesh subcaste. iii. It helps in defying tensile and punching shear.
3. sword Mesh underpinning sword morass are the primary underpinning for ferro cement. ii. The morass can be square woven or welded, or funk line morass of hexagonal shape and distance iii. In utmost sword morass, whether woven or welded, the parcels in the longitudinal and transverse directions are different. This is also applicable for hexagonal and expanded morass.
4. Fiber Reinforced Polymeric Meshes Steel underpinning has poor continuity and is susceptible to erosion. Fiber corroborated polymer is the stylish volition to sword morass. ii. FRP mounts made from carbon, glass, aramid, or other highperformance accoutrements bedded in polymeric matrices in the form of bars, tendons, and beaches are being produced and used these days.
Que5.15. Explain the colorful styles of manufacturing of ferro cement with their graces and faults.
Answer system of Ferro Cement Following are the colorful construction styles of ferro cement
1. Cadaverous system i. In this system a frame of buttressing bars( cadaverous sword) is constructed, to which a subcaste of morass is appliedFig.5.15.1. 5.15.1. Cadaverous architecture system. ii. Next, mortar is applied on one side and forced through the mesh until a slight excess appears on the other side. Advantages Following are the advantages of the cadaverous architecture system No elaborate form material needed. ii. Easy to patch up( form) the whole area from both sides. iii. Good penetration. iv. Easy to repair when damaged.
Disadvantages Following are the disadvantages of the cadaverous architecture system operation of mortar from one side may be delicate for a thick mesh system ii. Galvanic erosion may develop between the mesh and cadaverous sword iii. Embedment of cadaverous underpinning near the centre of the section leads to reduced performance in bending
2. Closed Mould Method i. In this system, several mesh or mesh- and- rod combination are held together in position against the face of a mould(Fig.5.15.2). ii. Mortar is also applied from the open side. The mould either remains a endless part of the structure or can be removed and reused. iii. In this system, a thin subcaste of mortar is placed first and allowed to settle, over which the mesh is placed and the alternate subcaste of mortar poured. This procedure is repeated until the needed number of subcaste are placed. 5.15.2. Closed mould system. Mortar from the side Impermable mould Bond swell at interface Advantages Following are the advantages of the unrestricted mould system Ideal for plant product since the exercise of moulds is permitted. ii. Cadaverous underpinning not needed. iii. Suitable for patented lay-up system.
Disadvantages Following are the disadvantages of the unrestricted mould system delicate to avoid internal voids, especially below underpinning mesh. ii. Complete penetration of mortar from one side may not be possible.
3. Integral Mould Method i. This system involves asemi-rigid frame,Fig.5.15.3. An integral mould may be formed using froth material similar as polystyrene or polyurethane as the core. ii. Mortar is poured from both sides of the mould. The mould is left inside the ferro cement itself. This system is ideal for field operation. 5.15.3. Integral mould system. Mould to remain inside Mortar Mortar Advantages Following are the advantages of the integral mould system Provides good severity. ii. Provides good water- miserliness. iii. Provides thermal sequestration. Disadvantages Following are the disadvantages of the integral mould system Special detailing is needed for acceptable shear connections between rigid ferro cement layers, especially across separating cores. ii. Both the sides need to be finished.
4. Open Mould Method i. The open mould system is a traditional system used for boat structure. ii. The open mould is made of chassis wood or some other suitable material and strengthened by caricatures. iii. The mortar is applied through one side only. iv. To grease mould junking, the mould is covered with a release agent or entirely covered with polyethylene wastes.Fig.5.15.4 illustrated the open mould system. Advantages Following are the advantages of the open mould system No cadaverous underpinning is needed. ii. More control of homestretches than the unrestricted mould system. iii. Moulds can be reused. Disadvantages Following are the disadvantages of the open mould system Framing and shoring system is expensive. ii. Complete penetration from one side isn’t guaranteed. iii. Amenable for any shape.
Que5.16. Explain the geste of ferro cement under pressure.
Answer geste of Ferro Cement in Tension
1. The typical cargo extension wind for corroborated concrete prism and ferro cement prism is shown inFig.5.16.1( a) and( b), independently.
2. The geste is substantially divided into three main stages Stage I Corresponds to the thrusting direct elastic portion of the wind( OA). ii. Stage II Corresponds to the unstable portion( AB) where cracking thresholds and stabilizes. iii. Stage III Where is cargo extension is nearly direct elastic and the crack range increase with an increase in applied cargo because of cracking. This stage exists until the buttressing sword yields. There will be only a many wide cracks across the sword.
3. FromFig.5.16.1, the main difference lies in unstable stage II( AB).
4. sluggishly adapts to the adding cargo by adding its extensibility. numerous fine cracks form. When cracks form, the increase in crack range is small compared to corroborated concrete.
5. Crack range in ferro cement can be one to two orders of magnitude lower than that of corroborated concrete. still, there are a number of fine cracks.