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- 1. BACHELOR OF QUANTITY SURVEYING (HONORS) CONSTRUCTION TECHNOLOGY III (BLD 60304) GROUP ASSIGNMENT GROUP MEMBERS : CHLOE SIM TIING ERN 0322932 CHIN KE NI 0324021 DEONG KHAI KEAT 0320055
- 2. Introduction to Industrialized Building System Industrialized Building System is also known as IBS. In Malaysia, the term ‘IBS’ is used for a construction technique which includes components being manufactured in a factory or in a controlled environment and then transported to a specific location for on-site fabrication where the structure is to be located. Generally, IBS is carried out in two stages, namely the manufacturing of components and fabrication of the components in position at the final location. IBS is largely promoted and recommended by the construction industries as implementing IBS into the construction help save a lot of time, money and manpower.
- 3. Introduction to Block Work System Block work system is an alternative method to the brick-laying task that is often seen during construction. Blockwork is a construction method where it uses concrete or cement blocks that are larger than standard bricks sizes. It is not constructed brick by brick but instead, it combines the standard concrete bricks into big blocks through prefabrication and are being installed on site. Block work system is one of the Industrialized Building Systems that have gained popularity for being convenient and cost effective even though additional finish is required. Block work system is widely used, especially to construct internal partition walls, retaining walls and load-bearing walls. Different types of blocks are used.
- 4. Manufacturing Process of Concrete Blocks There are four main processes associated with the production of concrete blocks, which includes mixing, molding, curing and cubing. 1. Mixing o Sand and gravel are moved from outside in piles into storage bins in the plant by a conveyor belt. The Portland cement in large vertical silos is kept outside to protect it from moisture. o When a production is in need, the amount of sand, gravel and cement needed will be transported by gravity or by mechanical means to a weigh batcher. A weigh batcher helps measure the exact amount of each material needed for production. o Then, the dry materials flow into a stationary mixer where the materials will be blended together for a few minutes. The most common type of mixers used are planetary, also known as pan mixer and horizontal mixer. The Planetary resembles a shallow pan with a lid with attached mixing blades at the vertical rotating shaft inside the mixer. On the other hand, the horizontal drum mixer resembles a coffee Cubing Curing Molding Mixing
- 5. can, turned to one side where the mixing blades are attached to a horizontal rotating shaft inside the mixer. o When the dry materials are properly blended, small amount of water is added into the mixer. The water has to go through a heater or chiller if the plant is located in extreme climate country to regulate its temperature. 2. Molding o The load of concrete is dumped into an inclined bucket conveyor once it is thoroughly mixed. It is then transported to an elevated hopper. The mixing step is repeated again for the next load. o The concrete is shifted to another different hopper on top of the block machine at a measured flow rate. In the block machine, the concrete is forced downwards into molds. The molds have an outer mold box that contains several mold liners. These mold liners help determine the outer shape of the block and the inner shape of the block cavities. o When the molds are full, the weight of the upper mold head compacts the concrete by pressing against the mold cavities. This compaction can be boosted by air or hydraulic pressure cylinders acting on the mold head. In most cases, block machines also use short burst of mechanical vibration to help with compaction. o Compacted blocks are pushed down and out of the molds onto a flat steel pallet. The pallet and blocks are then pushed out from the machine onto a chain conveyor. In certain cases, the blocks pass through a rotating brush that helps extract loose material from the top of the blocks. 3. Curing o The pallets of blocks are transported to an automated stacker or loader which places them in a curing rack. Each rack is able to hold a few hundred blocks at a time. There are 2 main types of curing kilns. The most common one is a low- pressure steam kiln. For this type, the blocks are held in the kiln for one to three hours at room temperature to allow them to moderately harden. To gradually raise the temperature at a controlled manner, steam is introduced to make sure it is not more than 60° F per hour. When the curing temperature has been reached, the steam is shut off and the blocks are left to soak in the hot, moist air for 12-18
- 6. hours. After soaking, the blocks are dried by draining the moist air and further raising the temperature in the kiln. 4. Cubing o The racks of cured blocks are rolled out of the kiln and then placed on a chain conveyor. The blocks are removed from the steel pallets and empty pallets will be inserted into the block machine to receive new set of blocks. o The blocks pass through a cube that aligns each block and then stacks them into a cube. These cubes are brought outside with a forklift and placed in storage.
- 7. Installing Process of Block Work 1. Preparatory Works o Make sure the details of the building layout are shown properly such as room dimensions, wall thickness, details of openings, locations of concealed items etc. 2. Block Work o Put a mark on the surface of wall to obtain proper layout of block work o Concrete or block work surface is cleaned and scrubbed using a suitable tool o Before starting block work, ensure reference points such as bench mark, cross beam level, lintel level etc. are checked properly. Must be sure where to terminate the top most block course. o Block has to be semi-dry or skin wet instead of damp during the starting of masonry. o Quantity of mortar is mixed well with proper measurement of ingredients. o Water is then added into the dry mix of cement and sand in necessary quantity. o Prepare a scheme of scaffolding, sketch and pass on to workers for execution. 3. Block Laying, Alignment & Jointing o One row of block work is done with “dry bond” to establish proper spacing of blocks o Mortar is laid for full bed width and length of 3 blocks at once
- 8. o Lay block by block gently and press it in the mortar bed o A line thread is used on one end to the other with a line pin o The block works must be plumb, square and bonded properly. Joints shall not be broken o Excess mortar coming out on the edge is removed by trowel o Thickness of courses has to be equal with courses horizontal o Use straight edge and spirit levels on top of blocks laid. Check and make sure spirit level is in working condition. o The last block is laid in the course. Close the bond and is placed near the center of the wall. Butter both edges of closure block with mortar before laying. o Above points are repeated for building more courses. 4. Striking of Joints o When mortars in the joints have set, a proper tool is used to strike the vertical joints and then the horizontal bed joints are raked. o After striking joints brush the wall surface head joint first and bed joints last to complete brushing.
- 9. Advantages of Block Work System 1. Consistent Quality Since concrete blocks are manufactured in a controlled condition using a manufacturing plant, the structure of each concrete block will be of uniform quality, have standard sizes and quality. Concrete blocks produced in a controlled manner do not need to rely on labour skills and craftsmanship so the overall quality of concrete blocks will not be affected. 2. Shorter Construction Time Generally, portable construction takes a shorter time to build than on-site construction. This is because prefabrication allows construction to be done off-site without being affected by bad weathers. Also, it is due to better upfront planning and prevent any scheduling delays. 3. Financial Savings Block work system is one of the ways to save money. Modular construction allows concrete blocks to be premade in bulks according to custom sizes. By using block work system, less labours are needed in brick laying. 4. Safety Since concrete blocks are made in a factory-controlled environment using mostly dry materials, problems associated with moisture, environmental hazards and dirt will not arise. Workers who work with these blocks will have less risk of getting into accidents as concrete blocks are bigger in sizes, which make them easier to cut and to install. 5. Waste Reduction Prefabricated construction helps minimize waste as the machine knows exactly how much product to produce. Block work system allows the manufacturer to produce desired amount of concrete blocks in standard sizes. This will not cause wastage and therefore cause less waste to be produced at site.
- 10. Disadvantages of Block Work System 1. Difficulties in Handling Transportation of concrete blocks to the erection site may cause breakages during the transit. Workers have to be extra careful when handling them. Also, the concrete blocks must be placed exactly in their required position on-site or else the other members will be affected. 2. High transportation cost High transportation cost is needed to transfer the concrete blocks from the factory to the site for erection. Since concrete blocks are bigger than normal, more transportation is needed to fit all of them, which lead to higher transportation fee. In certain cases, shipping is also needed if the location is too far away. Large amount of shipping also leads to high transportation cost. 3. Inflexibility Pre-cast elements do not allow these components to be altered. They are considered rather inflexible with respect to changes or renovations. It might face difficulty if additional conduit works need to be done.
- 11. CASE STUDY 1 : Residence in FELDA Laka, Kedah, Malaysia Description: The completed house was constructed in FELDA Laka, Kedah in 2008. It is a single-storey house with a built up area of 1571 sq ft. The construction time taken to complete the house was 40 days. It was designed and built by Teras Maju Dinamik Sdn. Bhd. using CCA interlocking blocks. This construction using load bearing interlocking block system. Construction Process: l The foundation, ground beam and ground slab is laid with the appropriate vertical steel implanted as shown in Figure 1(a). l It takes normally a week for the foundation to set then the first layer of load bearing interlocking blocks is arranged to ensure that the wall is straight and right angle at corner as shown in Figure 1(b). l After that, the workers can stack the blocks up to the required height independently. l Horizontal bars are placed for the construction of ring beam around the house for added stiffness as shown in Figure 2(a). l Moreover, similar process of arranging that block was done up to the roof beam where another two layers of channel blocks was used to simulate the roof ring beam as shown in Figure 2(b). l This process takes around two weeks to complete, then the roofing, plumbing, electrical, sanitary and finishing will take another two to three weeks to complete as shown in Figure 3. (a) Foundation slab (b) First layer of blocks
- 12. Figure 3 Final touches and the complete house (a) Below window level (b) Roof ring beams Figure 1 Typical construction site of an interlocking load bearing block house Figure 1 Typical construction of ring beams
- 13. Advantages: 1) The materials required for block production and building construction are usually locally available in most regions Ø Timber is expensive Ø Interlocking blocks have environmental advantages 2) Time saving Ø Dry assembly of interlocking blocks saves construction time 3) Cost saving Ø No need high-waged skilled masons Ø Save cement as less mortar is needed 4) Durability and stability Ø Grout holes and channel blocks provide means to insert steel reinforcements in vulnerable parts of buildings for increased wind and earthquake resistance Disadvantages: 1) Less resistance to wind and rain penetration Ø Even with the greatest care in assembling the walls, the joints are not entirely resistant to wind and rain penetration. Therefore, plastering the interior wall surfaces is necessary. 2) Lack of trained workers Ø Although skilled masons are not needed for constructing walls but certain training is required to ensure that the walls are properly aligned and no gaps are left.
- 14. CASE STUDY 2: Elme Hall Hotel Wisbech, Cambridgeshire Description: A new extension to the hotel created using Celcon Blocks with traditional mortar and cavity wall insulation. Elme Hall Hotel is a construction of a 34 bedroom building. The construction time taken to complete the hotel 12 months in total. Therefore, an aircrete solution was chosen by Project Manager Kevin Wood of Paktel Communications. £1 million for the whole project and approximately £200,000 for the blockwork elements.
- 15. Advantages: 1) Thermal Insulation • Excellent thermal insulation reduces energy use within a building. When combined with other building materials such as brick and insulation products, extremely low U- Values can be achieved. 2) Good thermal mass • Provides even temperature range in Winter or Summer. 3) Excellent sound insulation • Achieves superb sound insulation for internal partition walls • Celcon Blocks during manufacture actually help breakdown noise. 4) Fast to build with • Great productivity benefits from all Celcon products 5) User-friendly • Easy to achieve airtight construction • Easy to handle, easy to cut and forgiving to lay. 6) Lightweight
- 16. • Easy to transport • Reduces the building load in high rise construction • Can enable wider spans in beam and block floors Disadvantages: 1) Required skilled labours • Required to ensure that the walls are properly aligned and no gaps are left. 2) Loss resistance to wind and rain penetration • The joints are not entirely resistant to wind and rain penetration. Therefore, plastering the interior wall surfaces is usually necessary.