Interlocking Block Technology 5a3z4c

Topic Sustainable Building Materials Technology Interlocking Blocks

Name: Chaula Trivedi M.Arch ( Sustainable Architecture ) Sem I 2016-17

Bharati Vidyapeeth Deemed University College of Architecture, Pune-43

INTERLOCKING BLOCK CONSTRUCTION TECHNOLOGY 1 INTRODUCTION The dry stacked interlocking block masonry replaces the conventional brick and mortar construction masonry by interlocking blocks masonry construction. The other components of the conventional building system remain largely unchanged. The system is a dry stacked Interlocking masonry but can be done with mortar/slurry/grout also that enables aesthetic and affordable building, speedier construction of high quality in stretcher bond, and as well as in the normal English/Flemish bond with mortar. The blocks have an extremely appealing facebrick/wash finish and provide a pre-pointed straight masonry. The walls may be left exposed, plastered/rendered or finished with cement wash. The system has originated during the time of Egyptian pyramids construction and may be even before that period, and has extensively been in use over different continents. A number of constructions have been made using interlocking building system in India over last decades. The interlocking block masonry system is not uniform in India, and as per information available with the author, there are three types of interlocking blocks available (as per information available with author) in India: 1. Hydraform Interlocking Blocks ( stabilized earth blocks(SEB) and fly ash blocks 2. 2. IIT Delhi, India, fly ash interlocking blocks 3. 3. IIT Madras, India, cement concrete interlocking blocks Out of all these interlocking blocks, the author has the practical Out of all these interlocking blocks, the author has the practical working experience only with Hydra form interlocking blocks, and the same is explained in this paper. However the same is generic and can be extended with other types of interlocking blocks also. Stabilized earth blocks (SEB) are produced with local sandy loam type of soil with cement or lime or gypsum as stabilizer and are pressed in a hydraulic press in a mould, cured for 7 days and used as masonry blocks. The typical composition of SEB block chosen is given in table no 2 and fly ash block is given in table no 3.The amount of stabilization depends on the soil characteristics and strength desired, but generally varies from 2-10% by weight.

INTERLOCKING BLOCK TECHNOLOGY

Interlocking Profile The locking of a male face of one block with the female face of another or the locking of the bed of one block with the ridge of the one below , is called Interlock. Bed and Ridge The recessed under surface of the block is referred to as the bed. The raised top surface of the block is called the Ridge.

Corners Corner requirements are: Shaved ½ blocks is prepared. It must be ed to shave off the ridge and male face of the corner block, as shown in Figure 4, and further ensuring that the shaved ridge points upward and the shaved male face point’s outwards. One must start the first course with a ½ block. 2.6 Compatibility for Reinforcement for Earthquake Resistant Construction The interlocking blocks can be easily reinforced (because of the grooves) against the conventional masonry. All the relevant bands i.e. roof bands, gable band, lintel band, cill band and plinth band etc. can be easily incorporated in the masonry ( as per the requirements of the seismic design). Both vertical and horizontal Reinforcement can be provided by means of the grooves. The sizes of the grooves can be increased also. 2.7 Interlocking Masonry Features The interlocking blocks if made with fly ash combination has following unique advantages over other comparable products: • Density of masonry can be reduced in the range of 13 – 17kN/cum against the conventional fired brick system (19.20 kN/cum) in of unit weight. • High finish blocks are made; result in exposed finish aesthetic walls, saving on plaster/rendering & finishes. • Blocks can be made with lower water absorption properties making them useful for even relatively wet applications.

INTERLOCKING BLOCK TECHNOLOGY

• Dry-stacked masonry results in speedier construction. • Blocks can be made with reinforcement / conduit features facilitating earthquake resistant construction. • Blocks made are eco friendly as no burning is involved IThe Interlocking Building System t comprises of three primary aspects: (1) Interlocking Block (2) (2) Block making Machine (3) (3) Advantages of interlocked stacking of blocks Interlocking Masonry System The interlocking dry stacked masonry comprises of SEB (stabilized earth blocks) / fly-ash interlocking blocks that can be laid dry - stacked or using minimal mortar slurry/grout in a stretcher bond. Dry stacking is mortar- less method of masonry construction. Except first two block layers/courses above DPC( damp proof course of 40mm thick plain cement concrete of M20 mix at plinth level) and top two courses leading to roof band(if required ), blocks are not laid on mortar but can be laid with cement slurry, they rely on the interlocking mechanism to provide resistance to applied loads. Dry stacking results in reduction of building costs due to saving in construction time, reduced requirement for skilled labour and costly material especially cement and reusability of the blocks. The usage of unskilled labour makes dry stacking particularly attractive when compared with masonry with use of mortar. With an extremely appealing face-brick finish that provides for pre-pointed straight masonry, these blocks gives flexibility of achieving the final finish. The masonry uses minimal or no mortar, construction is fast, blocks are produced on the site saving transportation cost, requirement of skilled labour is reduced, blocks are water cured and do not require burning of fuel, wall face surfaces are even, plastering/rendering is not required but can be done as an option, the thickness of the masonry can be controlled giving more carpet area by using less cubic contents of the blocks, are advantages of using this masonry.

Bonding -Steel Bars & Conduits

INTERLOCKING BLOCK TECHNOLOGY

Construction Procedure A dry stacked interlocking masonry is laid on conventional strip footing. Foundation walls are built with blocks of higher strength laid in mortar bed or even conventional type foundation. Hudco (Housing & Urban Development Corporation, a government of India undertaking) has done a large number of construction using Hydra form Interlocking and other type of SEB (Soil stabilized Blocks), throughout India (Gujarat Earthquake Rehabilitation Works, Vivekananda Kendra, Kanyakumari, Development works around Qutub Minar Delhi and many more places and found these blocks suitable for masonry. However in all these places, cement slurry/grout was used to these blocks, as per IS 1905, as Indian Design Standards do not recognizes the Interlocking block based masonry, concept yet. Different conventional finishes can be applied to suit the aesthetic needs of the owner. Load Bearing Masonry Since blocks are 220 mm width and can be made of block strength > 75 MPa, same can be safely used for load bearing construction. Depending on structural requirements of the building, appropriate RCC bands can be used. Extensive tests have been conducted from time to time for conformity of dry stacked masonry in G+2 storey building. Fly Ash based interlocking blocks can be made of higher compressive strength to suit the load bearing construction requirements beyond ground floor to suit structural requirements. In of IS 1905, masonry can be done with thin mortar slurry of 1:3 to satisfy this requirement. Framed Structure Masonry Framed construction mainly require brick / block work to be used as an infill only, therefore dry stacked interlocking block work can be used in out walls of 220/230 mm thickness. For block work of lesser width it is recommended to use cement mortar slurry/grout. Blocks have standard height of 115 mm, makes it easier to design the beam height for required number of courses. Reinforced Masonry Interlocking blocks with horizontal and vertical cavity provide and ideal solution for using reinforcements to suit the structural design requirements, of reinforced masonry.

INTERLOCKING BLOCK TECHNOLOGY

INTERLOCKING BLOCK TECHNOLOGY

Interlocking blocks 2 Types of Bricks (based on Raw Materials) •Soil-Cement •Concrete

4 Types of Bricks (by size) Regular -15 cm x 30 cm x 10 cm Half -15 cm x 15 cm x 10 cm U-shape -15 cm x 30 cm x 10 cm U-half-15 cm x 15 cm x 10 cm

Construction with Interlocking Bricks • Load bearing construction system • No need for mortar between 2 layers of bricks • Reduces reinforcements as it eliminates concrete lintels, beams and columns • Cement based and Reinforced wall –resists fire, wind and earthquakes • Modular -No material wastage • Simple construction –with little training unskilled labor can be used to build the buildings • Cost-effective construction system • Can be use as composite structure

INTERLOCKING BLOCK TECHNOLOGY

Production of Soil-Cement Interlocking Bricks •Selection of raw materials •Preparation of Mixes •Filling mould box with mixes •Compression •Removal of brick and placing it on a pallet •Air curing / storage •Water curing •Testing

INTERLOCKING BLOCKTECHNOLOGY

Why Interlocking bricks? • Can be produced at or near the site –reduced transportation cost • Green technology –Zero carbon emission • Energy Efficient • Uses local available materials • Reduces the need for skilled labor • Maximize the use of unskilled labor • Faster to build –shortens construction time • Creates local employment • Permits self-help construction or community based projects • Can be used to build all types of buildings

Is it Expensive? Construction cost can be reduced as much as 50% in comparison with conventional system depending upon the local price. Initial cost for the equipments and trainings might seem big amount, but once it is in place, it will show that it is much cost –effective than traditional technologies. Thailand -20% to 40% Bhutan -40% to 50% Nepal-13% to 30% INTERLOCKING BLOCK TECHNOLOGY

Community Projects KhaoKhoResettlement Project, PhetchabunProvince, Thailand

•Location:-PhetchabunProvince, Thailand •Total no. of houses: -150 units •Floor area: -32 sq.m. x 2 storey = 64 sq.m. •Area of the Plot: -400 sq.m. •Construction cost: -approximately US$ 20 / sq.m. (500 Baht/sq.m.) •Total construction cost: -approximately US$ 1,300 (excluding labor cost)

INTERLOCKING BLOCK TECHNOLOGY

A concrete layer locks in the rebar beam, which is now covered and not visible, and the vertical rebar pictured.

Tie in corners, windows, doors and inner walls.

In low-seismic areas, dry-stacking the blocks without mortar is possible, but on this build in El Salvador, the rows of blocks sandwich a slurry made of the same dirt, sand and cement mixture of which the blocks are made. Every fifth row is mortared with cement.

Novice block layers can quickly learn to build straight, level walls. INTERLOCKING BLOCK TECHNOLOGY

Insertion of the electric box in the walls

Finished house

INTERLOCKING BLOCK CONSTRUCTION TECHNOLOGY DEVELOPED BY AUROVILLE • A technology using reinforced hollow concrete block has been developed all over the world since a while. Its principle is to reinforce the masonry by grouting a concrete into the holes of the blocks where stands a steel rod at the critical locations (Corners, ends, near openings, etc,). Horizontal reinforcements are also cast in blocks with a U shape. • The technology using Hollow Interlocking Compressed Stabilised Earth Blocks (HI CSEB) is based on the same principle: to reinforce horizontally and vertically the masonry with Reinforce Cement Concrete (RCC) . • The advantage of hollow interlocking CSEB, compared to hollow concrete blocks, is that they offer keys, which interlock in the other blocks. Thus these walls offer more resistance to shear and buildings would be even stronger. They would better resist earthquakes and without major damages. • Compressed stabilised earth blocks have another advantage: they are in most cases cheaper and they are always more eco-friendly than concrete blocks. • Compressed stabilised earth blocks have a poor bending strength but this is not so critical because the block itself will not bend but the masonry will do. CSEB have very poor shear strength, which is critical in the • case of earthquakes. Interlocking blocks will not have a stronger shear strength compared to ordinary CSEB. But the key effect will increase the shear strength of the masonry if the cohesiveness of the material is • high enough to keep the link between the key and the body of the block. (Especially shocks and vibrations of an earthquake) INTERLOCKING BLOCK TECHNOLOGY

Particular requirements for hollow interlocking blocks Interlocking blocks can resist disasters (Cyclones, earthquakes, tsunamis and floods), provided that they are hollow, so as to be reinforced with Reinforced Cement Concrete (RCC), at regular intervals. A hollow interlocking CSEB for earthquake resistance must satisfy these requirements: • Extreme consistency in height (1 mm difference maximum is allowed). • Self-aligning to reduce time-wasting adjustments. • Blocks should be hollow and the vertical holes and U shaped blocks should allow casting RCC, according to requirements: To reinforce regularly the masonry vertically and horizontally. • The interlocking keys must interlock transversally and longitudinally to the wall. They should interlock especially well in the length of the wall, which is subject to the shear stress of the earthquake. • Every course must interlock with each other as well as the header of every block in length: to increase the shear strength of the masonry. • Good seating of the blocks on top of each other for properly transmitting the load bearing: All the block area, including the key, must transmit the load. • The binder should be a cement-soil-sand (1: 1: 3) mortar of 5 mm thick. It should be quite fluid in order to be workable. • The mould must allow manufacturing full size blocks and 3/4 and 1/2 sizes. The blocks must not be cut to match the bond pattern, which will be detrimental to the accuracy, strength and quality of the masonry.

Hollow Interlocking block 245 (245 x 245 x 95 mm) “Running block”

Hollow Interlocking block 295 (295 x 145 x 95 mm) “Running block”

Hollow Interlocking block D300 (299 x 150 x 100 mm) “Running block”

This block 245 can be used up to two storey buildings. The block is laid with a stabilised earth mortar of 5 mm. A concrete grout is cast later on into the holes. The module of the block (dimension including the mortar thickness) is 25 x 25 x 10 cm.

INTERLOCKING BLOCK TECHNOLOGY

This block 295 can be used for single storey buildings only. The block is laid with a stabilised earth mortar of 5 mm. A concrete grout is cast later on into the holes. The module of the block (dimension including the mortar thickness) is 30 x 15 x 10 cm. This block D 300 can be used for single storey buildings only. This block is dry stacked and a concrete grout is cast later into the holes. This grout flows in all the holes as well as the vertical and horizontal ts due to the special profile of the block. The module of the block (dimension including the mortar thickness) is 30 x 15 x 10 cm • The accuracy of the Auram press allows a very regular block height: only 0.5 mm difference in height. This allows the block to get the ideal mortar thickness of 5 mm or to have dry stacked blocks which are then grouted with a concrete. The holes have been maximized (regarding the size of the block and the press design) at 5 cm diameter to allow a proper concrete cover for the steel. • The area of the key has been maximized at 9 cm diameter for the blocks 245 and 295, so as to ensure the maximum adhesiveness of the key on to the block body, so as to resist the shear effect. The height of the key has been determined by having the maximum friction area between blocks to resist the shear and by having the minimum friction on the mould while de-moulding the block from the press. The chamfer angle of the key seeks to be optimum. The keys of the hollow interlocking block Dry 300 are square so as to get an effective interlocking. The hollow interlocking block technology developed by the Auroville Earth Institute has been approved by three governments • The government of Gujarat, India, as a suitable construction method, up to two floors high, for the rehabilitation of the zones affected by the severe earthquake of January 2001 in Kutch district. • The Government of Iran (Housing Research Centre) as a suitable construction method, up to 8 m high (two floors), for the rehabilitation of the zones affected by the 2003 earthquake of Bam. • The Government of Tamil Nadu, India, (Relief and Rehabilitation) as a suitable construction method for the rehabilitation of the zones affected by the 2004 tsunami of Indonesia.

INTERLOCKING BLOCK TECHNOLOGY

Bibliography • 15th International Brick and Block Masonry Conference Florianópolis – Brazil – 2012 Sustainable Dry Interlocking Block Masonry Construction. • Interlocking Soil Soil-Cement Brick Technology Habitech Centera Research and Development unita unit for thefor theHousing and Building Housing Components. • Interlocking Block Construction Technology developed by Auroville.

INTERLOCKING BLOCK TECHNOLOGY