2.2 HOUSING INITIATIVE GLOBAL AND INDIAN SCENARIO

Affordability is defined based on a given context. To ascertain the affordable living, many countries came up with various programs and schemes. One such scheme is “Program Minha casa Minha Vida” of Brazil which was instituted in 2009 (Paulsen and Sposto, 2013). This scheme focused on developing over 7 million households (out of which 3.4 million are new) by providing financial assistance. Similarly, “Reconstruction and Development Program (RDP) houses” of South Africa is also an example of large-scale housing projects in the world.

The Government of India took its initial steps towards addressing the housing scarcity issue in the late 1980s, during the seventh five-year plan. The demand for housing in the country had been increasing significantly since independence. In response, the government established the Ministry of Housing and Urban Poverty Alleviation in 2004 to address the housing needs and improve the quality of urban living.

Since its establishment, the Ministry of Housing and Urban Poverty Alleviation has implemented various schemes and programs related to housing, employment, transportation, health, and cleanliness. One of the programs launched by the ministry is the Rajiv Awas Yojana, which aims to provide housing for the urban poor. Additionally, the ministry launched the Pradhan Mantri Awas Yojana (PMAY): Housing for All program, which focuses on ensuring affordable housing for all citizens.

The ministry consists of several entities, including the (CPHEEO), Public Sector Undertakings, subordinate offices, attached offices, and various statutory and autonomous organizations. The CPHEEO played a significant role in drafting the PMAY: Housing for All policy, while the (HUDCO) provided funding. Other supporting organizations include the (CPWD), Town & Country Planning Organization, (BMTPC), (DDA), and (CGWHO).

Pradhan Mantri Awas Yojna (PMAY) is a significant social housing scheme initiated by the GoI and implemented by the (MoHUA). The primary objective of this scheme is to provide affordable housing with basic amenities to the masses across India.

The PMAY mission aims to address the housing shortage faced by economically weaker sections (EWS) of society, including slum dwellers. It aims to ensure that every eligible household has access to a permanent house. The mission focuses on constructing houses with a carpet area of approximately 30-60 square meters, along with basic civic infrastructure, for the EWS population.

By implementing PMAY, the government aims to improve the living conditions of the economically disadvantaged sections of society and provide them with dignified and sustainable housing solutions. The scheme has a nationwide reach and seeks to bridge the gap in housing availability and affordability for the targeted population.

(Source:Author)

2.3 PAST REVIEW OF AFFORDABLE HOUSING TECHNOLOGIES

Various low-cost construction technologies have been developed and implemented worldwide, and some of them are relevant in the Indian context. Ongoing technological advancements are also introducing new materials for testing and exploration. For instance, the use of filler slabs instead of traditional slabs has the potential to reduce construction costs by 25% (Srivastava and Kumar, 2018). Furthermore, the establishment of cooperatives to provide alternative raw materials is expected to contribute to cost reduction by 20-30%.

In terms of sustainability, a life cycle study suggests that bricks made from cotton mill waste, recovered paper mill waste, and rice husk ash are more environmentally friendly compared to bricks made from burnt clay or fly ash. However, it should be noted that bricks made of clay can also be an eco-friendly choice in certain cases.

Another technology gaining attention is the use of bamboo-reinforced prefabricated wall panels. These panels are 56% lighter, 40% cheaper, and exhibit good strength when compared to partition brick walls, making them suitable for low-cost construction (Puri et al., 2017).

These examples highlight the potential for reducing costs and enhancing sustainability through the adoption of innovative low-cost construction technologies. By exploring alternative materials and construction methods, the construction industry can make significant strides towards achieving affordable and environmentally conscious housing solutions.

One of the significant challenges in implementing sustainable low-cost housing schemes is finding suitable land near the workplace of the residents. Long-distance commuting increases carbon footprint and undermines the sustainability goals (Goebel, 2007).

To address the issue of embodied energy in construction materials, (Larasati et al. 2017) proposed a method in Indonesia. They found a negative correlation between the building area and the embodied energy, suggesting that reducing the size of the building can help decrease embodied energy. This study emphasizes the importance of socializing embodied energy values to stakeholders, as it can have a significant impact on reducing the overall embodied energy in construction.

By focusing on locating housing projects near the workplace and promoting the awareness of embodied energy among stakeholders, sustainable low-cost housing schemes can make strides in reducing carbon footprint and improving energy efficiency. These approaches contribute to the overall sustainability goals and create environmentally conscious housing solutions.

2.4 ALTERNATE CONSTRUCTION TECHNOLOGY SYSTEM

With the global buzz about sustainability, reduction of carbon emissions, climate change mitigation strategies, the use of greener good practices in the construction sector has gained importance and has become relevant today. BMTPC under MoHua, Govt. of India has been promoting sustainable technologies for field level applications since 1990, however, during the last few years, BMTPC is in the process of mainstreaming alternate housing technologies other than conventional ones which are suitable for affordable mass housing especially in urban areas. These alternate construction systems offer a basket of appropriate structural systems which are not only superior to the existing RCC/load bearing construction practices but also deliver quality, safe & sustainable houses at a much faster rate with much improved functional performance. These are the some technologies along with other potential technologies under broad classification are as follows:

These systems are being used world over successfully and now most of the states in India along with govt. agencies & departments, construction agencies, development authorities & housing boards have shown interest & are willing to adopt them. About 1.4 million houses are being constructed with alternate construction systems in India under PMAY-U and other state-run schemes. These systems are sustainable systems and have potential to replace conventional methods of construction.

2.5 SELECTION OF SOME TECHNOLOGY BASIS OF THEIR U-VALUE

● Modular Tunnel form

● Insulating Concrete forms

● Plaswall Panel System

● Rapid Panel

● Quick Build 3D Panels

● Waffle-Crete Building System

● Walltec Hollow core Concrete Panel

2.5.1 MODULAR TUNNEL FORM

Tunnel formwork is a type of engineering formwork that replaces the traditional steel/plywood shuttering system. It consists of two half shells that form a room or cell when joined together, and several cells make up an apartment. This formwork allows the walls and slabs to be cast in one pour of concrete. Each phase is a part of the structure that will be cast in one day. The phasing depends on the schedule and the amount of floor area that can be covered in one day.

Some benefits of tunnel formwork are:

● It saves construction time.

● It reduces waste.

● It improves earthquake resistance with monolithic construction.

● It minimizes the number of joints with a single pour compared to other technologies.

● It produces a smooth surface that can be painted or wallpapered directly

Some challenges of tunnel formwork are:

● External walls made with RCC using this technology will have a high heat transfer.

● Modifications to these walls are very hard as they are structural.

● The formwork has little room for variations and works only if the units are repeated.

2.5.2 INSULATING CONCRETE FORMS

Insulating Concrete Forms (ICF) and Monolithic Insulated Concrete Systems (MICS) consist of expandable polystyrene (EPS) panels with two walls, separated by hard plastic ties at a fixed distance of 150mm. These panels are assembled on-site to create a shuttering system. By pouring concrete into the hollow space, a solid wall is formed, which provides structural support for floors and roofs. Additionally, the EPS panels serve as insulation, offering thermal protection.

Some benefits of ICF and MICS are:

● They save construction time.

● They reduce labor demand.

● They have one of the best insulation values & Thermal Performance among the technologies studied.

● They have better sound proofing qualities.

● They have better earthquake resistance.

Some challenges of ICF and MICS are:

● Wall thicknesses are fixed.

● Position of doors and windows are very hard to change after construction.

2.5.3 PLASWALL PANEL SYSTEM

This particular formwork system is designed to remain in position and involves the use of two 6mm-thick fiber cement boards (FCB). During construction, High Impact Molded Inserts (HIMI) are attached between the FCB sheets on-site, creating a wall that is ready for finishing. To achieve a monolithic structure, the entire form is filled with concrete of M20 grade. By incorporating additional reinforcing bars or using a higher grade of concrete, the load capacity of the structure can be enhanced.

Some benefits of this formwork system are:

● It is 30-50% faster.

● It reduces labor cost.

● It does not need on-site curing.

● It avoids plastering.

● It provides better earthquake resistance.

● It does not need a crane and hence can be used in small scale projects.

One challenge of this formwork system is:

● The Fiber Cement board that is made in India is brittle and of poor quality hence it must be imported from Malaysia or Philippines.

2.5.4 RAPID PANEL

The Rapid Panel is a preconstructed system consisting of high-strength steel wire assembled into a three-dimensional framework, with a core made of expanded polystyrene (EPS). During construction, these panels are used as walls and/or slabs. The panels are coated with specified mortar or concrete mixtures to finalize the structure. The primary component of the panel is the zig-zag truss, where steel wire is shaped into a continuous chain of web members in a zig-zag pattern. This bent wire is then welded to continuous chord wires at each connection point, creating the complete truss structure. The manufacturing of Rapid Panels takes place in a fully automated facility.

Some benefits of Rapid Panel are:

● Formwork panels do not need a crane hence smaller projects are also possible.

● 30-40% less time needed in construction.

● Up-to 30% labor savings in labor.

● 35-40% reduction in the dead load.

● Beams can be avoided till a certain span when used as a roof slab.

Some challenges of Rapid Panel are:

● Load Bearing structures are only possible till G+3.

● Panels are not made in India. They are made in Mexico and 50% of the panel cost is due to transportation.

● Steel wires puncturing the EPS panel will act as thermal bridges.

2.5.5 QUICK BUILD 3D PANELS

The quick build 3D Panel system utilizes panels composed of a fire-resistant insulated polystyrene core, along with two engineered layers of Galvanized Steel Mesh and galvanized steel trusses. The steel trusses are inserted through the polystyrene core and welded to the outer layer sheets of Galvanized steel mesh. When the wall panel is positioned, a structural plaster is applied to both sides. The strength and rigidity of the wall panel are derived from the diagonal cross wires that are welded to the welded-wire fabric on each side. This combination creates a truss-like behavior, offering both rigidity and shear capabilities for a fully composite effect.

Some benefits of 3 D Panel system are:

● EPS used is of zero-toxicity (food grade).

● Monolithic structures have earthquake resistant properties.

● Steel used is galvanized which prevents rusting and increases its life.

● It offers 1.5 times more longevity than conventional structure.

● Up to 10-20% components are recycled.

● Fly ash is used in the concrete.

● Beams can be avoided till a certain span when used as a roof slab.

Some challenges of 3 D Panel system are:

● Steel used in the construction is imported from China because of quality issues in India.

● Thermal bridges formed within the panels that would increase the heat transfer of assembly.

2.5.6 WAFFLE-CRETE BUILDING SYSTEM

The Waffle-Crete Building System utilizes sizable ribbed panels made of reinforced precast concrete. These panels are securely fastened together through bolting, and the connections between the panels are sealed with caulk. This assembly method allows for the creation of walls, floors, and pitched or flat roofs in buildings.

Some benefits of Waffle-Crete Building System are:

● There is a reduction in labor cost.

● 35% reduced construction time.

● Steel requirement is reduced if roof and wall both use this technology.

● Columns and beams are avoided.

● Shuttering cost is avoided.

● Plastering can be avoided.

● On site material wastage is reduced.

● Technology can be used anywhere.

Some challenges of Waffle-Crete Building System are:

● The services are unconcealed.

● Heat transfer is very high however insulation can be added for extra cost.

● A structure higher than G+3 is yet to be built.

● Only standard sizes available, custom sizes need to be specially made.

2.5.7 WALLTEC HOLLOW CORE CONCRETE PANEL

Walltec wall panels are non-load bearing concrete hollow core panels manufactured using automated machines. These panels are produced in a factory setting and consist of lightweight concrete composed of river sand, crushed stone aggregate, lightweight aggregate, and Ordinary Portland cement.

Some benefits of Walltec wall panels are:

● Faster Construction with a strict time frame.

● Wastage is minimized due to prefabrication.

● Shuttering cost is avoided.

● Plastering can be avoided.

● Damaged panels can be recycled into aggregates for further panels.

● No curing onsite needed hence less water consumption.

Some challenges of Walltec wall panels are:

● Cranes are needed for installing panels.

● Difficult to be used for external walls as scaffolding would be required on the outside

● Coordination issues occur when used in conjunction with other technologies.