20 November 2018

Industry Focus- Precast Concrete & Equipment

Precast Concrete: The new dimension of construction

 

Most of the developing nations are today facing a massive crisis situation— housing. Though most of them have got acquainted and found out solutions to deal with the problem, there is always a need to find alternative measures to face this growing problem. This is where Precast concrete construction technology acts as a promising solutions to meet the huge housing demand. Precast is fast, healthier and safer. In addition to the benefits of this, the national initiatives aimed at prioritising infrastructure and house building has propelled the demand for precast concrete products and equipment feels ROHAN AMBIKE.

 

 

The housing sector in India has been the greatest demand driver for cement, which, according to experts, amounts to around 67 to 70 per cent of the total consumption. As the name suggests, Precast Concrete is a technology where precast components are fabricated or assembled offsite, transported to the project site, and mounted on a ready foundation. The process involves casting of concrete in a reusable mold or form. Before it is ready to be transported, the concrete is cured in a precast plant under a controlled environment unlike a standard concrete, which is poured into site-specific forms and left to be cured there. The industry manufactures precast and pre-stressed concrete products for use in varied construction activities. The list of products are- precast concrete slabs and panels, building boards, roofing tiles, railroad ties, posts, poles, pre-stressed bridge beams and trusses. According to the Report of the Technical Group on Urban Housing Shortage (2012-2017) (Ministry of Housing and Urban Poverty Alleviation), Rural Housing for XII Five Year Plan (2012-2017) (Ministry of Rural Development, Government of India, 2011) and KPMG analysis in India (KPMG, 2014), the development of this ambitious program requires about 11 crore houses by 2022 with investments of over $2 trillion. The urban housing accounts for about 85-90 per cent of the total investments and affordable housing requirement is about 70 percent of total investments. To meet this huge urban housing demand, precast concrete construction industry can play a crucial role.

 

 

Precast concrete is a value-for-money product that scores over traditional concrete in the long run since the mold can be reused several times over. Major advantages of precast technology include quality, speed of construction, and cost-effectiveness. It helps avoid labour shortage and unforeseen delays. Since it is made at the ground level, the safety aspect is also well taken care of. In addition, the material quality and workmanship can be monitored more efficiently in a precast plant than at the construction site. In contrast, onsite casting gets expensive as cost calculation is done for every unit of formwork. Precast concrete products are sufficiently strong to withstand extreme conditions of weather and are able to hold its strength for decades despite constant usage.

 

 

FAST FACTS:

 

  •  The precast concrete market was valued at $99.13 in 2016 and is projected to reach $138.96 billion by 2022.
  •  The urban housing accounts for about 85-90 per cent of the total investments and affordable housing requirement is about 70 per cent of total investments.
  •  Precast concrete construction will save valuable time and helps to reduce the risk of project delay and possible monetary losses.
  •  The Indian construction industry is presently estimated to be worth around $740 billion.

 

 

Advantages of precast concrete

Some of the advantages of using precast concrete construction are as follows:

 

 

Reduced Construction Time and Cost

 

Precast concrete construction will save valuable time and helps to reduce the risk of project delay and possible monetary losses. Precast design and production of elements can be started while the construction site is under survey or earthworks. Production is also unaffected by weather conditions due to the controlled environment of the casting area. Also, the usage of large precast panels will reduce the time taken to complete the structural works. Therefore, other trades such as painting and electrical wiring can begin work sooner.

 

 

High quality and aesthetical value of products

 

Precast products are manufactured in a casting area where critical factors including temperature, mix design and stripping time can be closely checked and controlled; and this will ensure that the quality of precast products are better than cast-in-situ concrete. A huge sum of money will be saved by not having to do rectification works. Also due to factory-controlled prefabrication environment, many combinations of colours and textures can be applied easily to the architectural or structural pieces. A vast range of sizes and shapes of precast components can be produced, providing a great deal of flexibility and offer fresher looks to the structures.

 

 

 

Cleaner and safer construction sites

 

Usage of precast elements eliminates or greatly reduces conventional formworks and props. Precast construction also lessens the problem of site wastages and the related environmental problems. The prefabricated products also provide a safe working platform for workers to work on. Workers and materials are also greatly reduced at the construction sites. Using Just-in-Time principles, the precast elements are kept at the factory yard until the site is ready for installation. Also, as elements are produced in the plant and mostly designed to be repetitive, minimal wastage will be experienced at both factory and construction sites.

 

 

Lower total construction costs

 

All of the above simplify the construction processes and increase productivity, quality and safety. As a result, the total costs of construction are reduced. More often than not, most of the opponents of precast construction only use the costs of materials in comparing the in-situ and precast construction without realising that there are hidden costs to the traditional methods. Also a contributing factor to the low usage is the fact that Malaysia has always been able to source cheap labours from neighbouring countries. Therefore, the industry players are very reluctant to change to the new construction methods. As a result, the country is faced by problems of low quality, productivity and safety in the construction industry due to high dependency of manual labour. The country also suffers from the outflow of monies as well as social problems. If the labour supply experience sudden reduction while demand remains the same, labour costs will definitely be increased and produce more problems to the industry.

 

 

 

Increased Quality of Structural Elements

 

Precast concrete elements produced in plants using modern techniques and machineries. Raw materials such as concrete, sand, and reinforcement bars are under high level of quality control. Formworks used are of higher quality than those used at construction sites. This allows truer shapes and better finishes in precast components. Precast components have higher density and better crack control, offering better protection from harsh weathers and sound insulation. High density is achieved by using vibrating table or external vibrators placed on formworks. Precast concrete also provide better fire resistance for reinforcement bars. When compared to in situ concrete, this reduces the amount of long-term movement, which needs to be recognized in building design.

 

 

 

Disadvantages of Precast Concrete

Some of the drawbacks of using precast concrete construction are as follows:

 

 

High Capital Cost

 

A large amount of resources must be invested initially to set up a precast concrete plant. Sophisticated machineries are expensive and require heavy investment. Percast concrete is mainly used in construction of high-rise buildings and flats, which are at least 5 storey high. Precast concrete is also utilized in construction of housing estates where the design of houses is uniform. Other projects where precast concrete is suitable are large stadiums, halls, factories, warehouses, airports and hangars. The scale of the construction projects using precast concrete must be large enough to ensure sufficient profit to offset the initial capital cost.

 

 

 

Sophisticated Connection Works

 

The behaviour of connections determines the performance of precast concrete structures. When assembling of precast concrete structures, connections between precast components must be supervised and done properly. This way, the intended behaviour of a connection (simple, semi-rigid, or rigid) can be achieved. Apart from that, a good sound insulation can be provided and water leakage problem can be avoided. Skilled and well-trained labours are required to ensure proper connection is produced during erection stages, which lead to additional cost.

 

 

 

Transportation, Handling Difficulties and Modification Limitation

 

Workers must be careful when handling precast concrete components to avoid damage. Precast components are manufactures in plants, which are not always situated in the area of the construction sites.

 

 

Precast components must be carried from the plants to the sites using trailers. Usually, precast components are large and heavy, creating difficulties in transportation. Upon arrival at the sites, portable cranes or tower cranes will lift the precast components into place for erection. Usually, to increase the speed of construction, several cranes are used requiring large space. Proper construction planning and site management is a must.

 

 

Workers be well trained to ensure that precast components are positioned and connected properly to avoid cases where the columns, beams, walls, or slabs are not well aligned, dislocated or out of plane. Precast concrete system is not flexible when future modification is taken into account. For example, the walls of a flat built using load bearing precast walls cannot be demolished for renovation purposes, as this will affect the stability of the entire precast structure.

 

 

 

Trends in Precast Market

 

Numerous advances have been made in all areas of concrete technology including materials, mixture proportioning, recycling, structural design, durability requirements, testing and specifications. Throughout the world some progress has been achieved in utilizing these innovations but largely these remain outside routine practice. The high performance concrete (HPC) for transportation structures, e.g., bridges and pavements, are gaining wider acceptability in routine practice. HPC provides enhanced strength and durability properties and contributes towards long lasting structures and pavements. Here are some of the ongoing trends in the precast concrete industry.

 

 

 

Green Cements

 

Research has been carried out to develop non-clinker “green” cement using two industry wastes: cement kiln dust (CKD) and fly ash (FA). CKD contains partially calcined materials with some hydraulic and cementitious properties. It also has high alkali, chloride, and sulfate content, which may cause problems in cement performance.

 

 

 

Smart Concrete

 

Concrete has been widely used for many years as a composite material for various types of structures. One of the weaknesses of concrete is that it cannot withstand tension which can cause cracks easily. There has been a huge demand to monitor concrete structures cracking and preventing them from propagating further.

 

 

These efforts are important for timely repair, safety and long-term durability of critical structures. Non-destructive evaluations, such as attaching or embedding sensors into structures, have been used in many ways to accommodate the demand, yet the tests are considered expensive.

 

 

 

Market Trends

 

The precast concrete market was valued at $99.13 in 2016 and is projected to reach $138.96 billion by 2022, at a CAGR of 5.96 per cent. The base year considered for the study is 2016, and the market size is projected from 2017 to 2022. The biggest drivers for precast are the Smart Cities domain, Affordable housing and infrastructure projects. Still in its infancy in India, early movers in precast materials and equipment will emerge entrenched players in the long-run.

 

 

 

Technology Trends

 

The government has already identified infrastructure sector as one of the key drivers of economic development. A big chunk of the demand for India’s construction sector comes from the infrastructure sector. Since precast is essentially linked to construction, any thrust in the infrastructure sector will benefit precast segment. Hence, an increase in public spending will increase demand for precast concrete.

 

Trillion-dollar investment projects like 100 Smart Cities and ‘Housing for All’ are ready examples of the government thrust. Precast (prefabricated) construction technology will be required to construct large projects like bridges, metro rail, highways, and other transportation infrastructure.

 

 

 

Conclusion

 

The Indian construction industry is presently estimated to be worth around $740 billion. Of this, precast concrete technology commands only 2 per cent vis-à-vis the traditional methods of construction. The industry is confident that in the coming years, every state will have precast plants numbering 20 or more.

 

However, the developers are looking forward to appropriate tax benefits and lowering of custom duty on imported technologies. Once that gets taken care of, the sheer size of demand will easily make India a major global market for precast technology.

 




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