Behaviour of Interlocking Hollow Concrete Blocks

India is one of the highly populated countries of the world. It ranks the second in population n Be sides, major section of the people live below poverty line. Due to over population, poverty, high land value & house deficit, major cities like Delhi & Mumbai are covered by slums. These slums not only make our country aesthetically bad but also the people living in such slums are deprived from basic facilities like proper sanitation, health care, and proper housing. The provision of affordable housing for these poor people needs to be facilitated by certain provisions. This can be possible only by introducing such technologies and materials that can be beneficial for building low-cost houses. Researchers worldwide have made significant efforts to find sustainable and affordable technologies to arrest the situation. Appropriate solution for affordable housing will vary from one location to another. Some general rules, however, apply to construction methods and housing systems. This project aims for developing a technology called dry stacking or mortar less buildings made from interlocking blocks. Mortar less brick construction, usually employing interlocking bricks, is growing in popularity round the world, indicative of acceptability. Mortarless techniques demonstrate the following advantages: increase of construction productivity, reduction in construction duration and lab or and reduced construction cost. Because of its technological simplicity and local resource dependence, mortar less-block construction is more appropriate to many local communities than conventional mortared-brick techniques. .ijtsrd.com | Volume – 2 | Issue – 5 | Jul-Aug 2018 6470 | www.ijtsrd.com | Volume Journal of Trend in Scientific and Development (IJTSRD) International Open Access Journal , Mr. Chitranjan Kumar Student, Assistant Professor -Falah School of Engineering and Technology ext to China. INTRODUCTION Masonry construction of structures offers many advantages over traditional wood framing, including increased strength, fire resistance and insulation value. Traditionally, masonry construction techniques involved taking masonry units, typically manufactured cement, sand, water & aggregate, “buttering” the units with mortar, typically mixed from cement, sand water and lime, buttered units to form a number of courses. However, this technique has a number of disadvantages. First, the weakest part of such a masonry wall is the mortar joint, as the substitution of lime for aggregate reduces the overall strength of the joint. Second, the need to butter and precisely fit each block necessitates the use of skilled, and typically highly paid, masons. Finally, the mortar used to butter the units often hardens on the inside of openings within the blocks, preventing or hindering the insertion of insulation and/or reinforcements within the openings. One solution to the lack of strength of mortar joints has been to dry stack the masonry units. In a typical dry stacked wall, the masonry units are stacked in a staggered arrangement and are reinforced by inserting steel rebar through interlocking holes. Once reinforced, a skin made up of fibreglass and a cementicious material may be applied to the front and back faces of the walls to provide additional reinforcement. Adding the skin to the front and back faces of the wall increases the stability of the wall by up to ten times the stability of a wall without such a skin and provides an additional barrier to prevent cold and warm air from passing through the joints between masonry units. Therefore, the use of such a skin is preferred in these types of walls. However, dry stacking of walls is not without drawbacks. First, like the staking of mortar walls, care must be taken to ensure that the Page: 1853 2 | Issue – 5


INTRODUCTION
Masonry construction of structures offers many advantages over traditional wood framing, including increased strength, fire resistance and insulation value. Traditionally, masonry construction techniques involved taking masonry units, typically manufactured cement, sand, water & aggregate, "buttering" the units with mortar, typically mixed from cement, sand water and lime, buttered units to form a number of courses. However, this technique has a number of disadvantages. First, the weakest part of such a masonry wall is the mortar joint, as the substitution of lime for aggregate reduces the overall strength of the joint. Second, the need to butter and precisely fit each block necessitates the use of skilled, and typically highly paid, masons. Finally, the mortar used to butter the units often hardens on the inside of openings within the blocks, preventing or hindering the insertion of insulation and/or reinforcements within the openings. One solution to the lack of strength of mortar joints has been to dry stack the masonry units. In a typical dry stacked wall, the masonry units are stacked in a staggered arrangement and are reinforced by inserting steel rebar through interlocking holes. Once reinforced, a skin made up of fibreglass and a cementicious material may be applied to the front and back faces of the walls to provide additional reinforcement. Adding the skin to the front and back faces of the wall increases the stability of the wall by up to ten times the stability of a wall without such a skin and provides an additional barrier to prevent cold and warm air from passing through the joints between masonry units. Therefore, the use of such a skin is preferred in these types of walls. However, dry stacking of walls is not without drawbacks. First, like the staking of mortar walls, care must be taken to ensure that the

Behaviour of Interlocking Hollow Concrete Blocks
Engineering and Technology Masonry construction of structures offers many advantages over traditional wood framing, including ire resistance and insulation value. Traditionally, masonry construction techniques involved taking masonry units, typically manufactured cement, sand, water & aggregate, "buttering" the units with mortar, typically mixed from cement, sand water and lime, and stacking the buttered units to form a number of courses. However, this technique has a number of disadvantages. First, the weakest part of such a masonry wall is the mortar joint, as the substitution of lime for aggregate reduces f the joint. Second, the need to butter and precisely fit each block necessitates the use of skilled, and typically highly paid, masons. Finally, the mortar used to butter the units often hardens on the inside of openings within the blocks, preventing or indering the insertion of insulation and/or reinforcements within the openings. One solution to the lack of strength of mortar joints has been to dry stack the masonry units. In a typical dry stacked wall, the masonry units are stacked in a staggered gement and are reinforced by inserting steel rebar through interlocking holes. Once reinforced, a skin made up of fibreglass and a cementicious material may be applied to the front and back faces of the walls to provide additional reinforcement. Adding skin to the front and back faces of the wall increases the stability of the wall by up to ten times the stability of a wall without such a skin and provides an additional barrier to prevent cold and warm air from passing through the joints between masonry units. Therefore, the use of such a skin is preferred in these types of walls. However, dry stacking of walls is not without drawbacks. First, like the staking of mortar walls, care must be taken to ensure that the International Journal of Trend in Scientific Research and Development (IJTSRD) ISSN: 2456-6470 @ IJTSRD | Available Online @ www.ijtsrd.com | Volume -2 | Issue -5 | Jul-Aug 2018 Page: 1854 units are properly aligned with one another. This can be a painstaking process that greatly increases the time required to build such a wall. Second, the lack of motor in the joints between units allows air to easily pass through the joints and requires that a skin or other air barrier be used in connection with the walls. Third, the lack of mortar to hold the units in horizontal alignment make the use of many additional reinforcements, such as steel rebar, stabilizers, or the like, absolutely necessary in these types of walls. At the inner end the key has a width of 40mm, protruding out to a width of 60mm on the outer side.

MATERIALS USED AND TESTING
The key fits into the groove and this is how interlocking is achieved in the stretcher coarse. There is no top-bottom interlock, so mortar is used between coarse.

TYPE-B
It is a single block with key on one end and groove on other, key at top and grove at bottom. The block has a dimension of 400mm x 200mm x 200mm. The hollow portion is divided into two parts. The end interlocking is dovetail shaped and the top bottom interlocking is rectangular. The top-bottom interlocking is so designed to have a have overlap between coarses while constructing a wall. Again the minimum thickness of the block on each side is 40mm. The rectangular keys have a dimension of 40mm x 20mm. Distance between two inner rectangular interlocks is 20mm.

TYPE-C (FEMALE)
It comprises of key on one end and groove on other + two grooves on the front. The block is 400mm x 200mm x 200mm with side key and a groove as in first model. In addition to that it has two grooves on the front which makes it a female block. The front keys are also dovetail shaped as the side keys. This block has no top-bottom interlocks making it necessary to use mortar in between coarses. The block is used in the construction of a 400mm thick wall.

TYPE-C (MALE)
It consists of key on one end and groove on other + two keys on the front. The block has a dimension of 400mm x 200mm x 200mm. It is the male block for Type-C (FEMALE) block. It has a dove tail key on one end with a dovetail groove on the other end. In addition it has two dovetail keys on the front, specifying it male. The minimum thickness of the block is 40mm from all sides. It's used with its female block for 400mm thick walls. Without top-bottom interlocks, motar is to be used between coarses.

TYPE-D (FEMALE)
In this type there is key and groove on sides + two grooves on front + keys on top and grooves on bottom side. The block has a dimension of 400mm x 200mm International Journal of Trend in Scientific Research and Development (IJTSRD) ISSN: 2456-6470 x 200mm with a groove on one side and a key on the other both being dovetail shaped. Two dovetail shaped grooves are present on the front making it of female type. It eliminates the use of motar bed completely since it is provided with rectangular keys on the top and two rectangular grooves on the bottom. The female block along with its male block is used in the construction of 400mm thick wall.

TYPE-D (MALE)
It comprises of key on one end and groove on other + two keys on front +keys on top and grooves on bottom side. This block has dovetail shaped key on one and a groove on the other end. Two dovetail shaped keys occur on the front. Four rectangular keys are on the top and four rectangular grooves on the bottom. The size of the keys and grooves are same in all the cases and has been mentioned in the first two models

COARSE AGGREGATES
Aggregates of size 6mm-10mm have been used. Aggregates of desirable size were separated by sieve analysis. Following tests were performed on coarse aggregates:   Vol. of coarse aggregates for .0116 m 3 concrete=.0116 m 3 ×.5713=6.62× 10 -3 m 3 1 m 3 of coarse aggregates = 1560 kg 6.62× 10 -3 m 3 of coarse aggregates = 6.62× 10 -3 ×1560 =10.33kg Quantity of water for 2.46 kg of cement = water-cement ratio × quantity of cement = .5× 2.37 = 1.18 kg or 1.18 litres. From the data available it is concluded that 1. The compressive strength interlocking blocks is 6-9 MPa and that of prisms is 5-8MPa which is almost same. 2. The compressive strength of individual blocks is much better than traditional briks and concrete blocks. 3. The stiffness of prism C1 is maximum 4. The interlocking blocks results in speedier construction thereby saving money and time. 5. It eliminates mortar bed completely which otherwise proves to be the failure bed for diagonal tension. 6. It results in a labor cost reduction of up to 80%.

COMPRESSIVE STRENGTH OF BLOCKS COMPRESSIVE STRENGTH OF TYPE-A
Because these are self aligning thus reduce time wasting adjustments. 7. Hollow nature makes these blocks perfect for sound and heat insulation.

FUTURE SCOPE
The interlocking blocks discussed in our project can be modified in future by: 1. The use of reinforcing in the pins provided. 2. Use of steel strips or steel plates in pins. 3. Use of lateral tie rods grouted to the blocks to increase their integrity. 4. Use of vertical rods in the hollow portion provided which are then held in position by grouting. This increases integrity between different coarses. 5. Use of such rods increases the tensile strength of rods thereby increasing their overall strength and hence making them useful for seismic areas as well. 6. Use of light weight materials like fly ash so that blocks can be lifted, transported and placed easily