INTRODUCTION Need of the area One of the major causalities of heavy reliance on labour intensive techniques of construction is the quality of work

INTRODUCTION
Need of the area
One of the major causalities of heavy reliance on labour intensive techniques of construction is the quality of work. Site-mixed concrete has serious limitations as far as quality of concrete and speed of construction are concerned. Now growing realization is surfacing that quality and consistency cannot be achieved by relying on age-old techniques of construction. Huge amount of time and manpower can be saved by implementing mechanization in concrete industry through Ready Mix Concrete.

Potential of the area
In industrialized countries ready mix concrete forms around 70-75 per cent of the market share. The global ready-mix concrete market size was valued at USD 492.2 billion in 2015. With India building up its infrastructure and cities see a spurt in verticalization the ready mix sector is expected to play an increasingly dominant role mainly because it is seen as the most viable option to speed up construction. RMC is also being increasingly preferred alternative for most real estate developers because site mixed concrete is dependent on the availability of labour. While earlier, demand for RMC was largely seen in the metros, the industry has now grown to all parts of the country including Tier 2 and 3 cities. From 2011-2018 construction industry has contributed an average of INR 2108.80 billion per quarter towards the GDP. The RMC market in India is estimated to be worth INR 5194.2 billion by 2024.

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Objective
The objective of this report is to know about the origin of the Ready Mix Concrete, development of RMC throughout the world, Indian scenario in the past years, barriers to the growth of RMC industry in India, need of the industry in India and various types of Ready Mix Concrete plants etc.
WHAT IS AN RMC PLANT?
Ready Mix Concrete(RMC) plant, also known as batching plant is where concrete is prepared using a set recipe and required raw materials.
Ready-mix concrete is often preferred over on-site concrete mixing because of the precision of the mixture and reduced work site confusion.

HISTORY BEHIND RMC PLANT:
Ready-mixed concrete was first patented in Germany in 1903, but the means of transporting it had not been developed sufficiently by then to enable the concept to be commercially exploited. The first commercial delivery of RMC was made in Baltimore, USA in 1913 and the first revolving drum type transit mixer, of a much smaller capacity than those available today, was born in 1926.
By the late 1920s and 1930s, RMC was introduced in some of the European countries. After the world war-2, there was a boost to the RMC industry in whole of Europe, including the UK. In the mid-nineties, there were as many as 1,100 RMC plants in UK, consuming about 45 percent of the cement produced in that country. In Europe, the European Ready Mixed Concrete Organization (ERMCO) was formed in 1967 and is a federation of the national associations of the 22 countries. As of in 2013 there are 5,850 companies represented by it having a turnover of 13.11 billion Euros and producing a total of 349.4 million m3 of RMC. Cement consumption averaged 60.8 percent of total cement sales, and RMC consumption of 1.2 m3/capita/annum.
In USA, till 1933, only 5 percent of the cement produced was utilized through the RMC route. American Society for Testing Materials(ASTM) published the first specification of ready-mixed concrete, C34, in 1934. The industry in USA has progressed steadily. During 1950 to 1975, the RMC industry’s consumption of total OPC used in the USA increased from 1/3rd to 2/3rd and by 1990, this consumption increased to 72.4 percent of the total OPC consumed in that country. There were as many as 5,000 RMC companies in the country in 1978. During 2013, RMC production in USA was 115million m3 and turnover of 15.6 billion USD.
In Japan, the first RMC plant was set up in 1949. Initially, dump trucks were used to haul concrete of low consistency for road construction. In the early 1950s, mixing type truck mixers were introduced and since then there has been a phenomenal growth of the industry in that country. By 1973, there were 3,413 RMC plants in Japan and this number rose to 4,462 by the end of the 1980s. By 1992 Japan was the then largest producer of RMC, producing 181.96 million tons of concrete per annum. During 2013, Japan produced 86 million m3 concrete and turnover of 10.50 billion USD.

In many other countries of the world, including some of the developing countries like Taiwan, Malaysia, Indonesia, as well as certain countries in the Gulf region, the RMC industry is well-developed today.

The growth pattern of RMC world over can be divided into three phases. The phase 1 or the introduction phase is considered up to 10% cement consumption by the RMC industry. The phase II or the growth phase is assumed up to 50% cement consumption and phase III or consolidation phase is considered thereafter. During the consolidation phase, the growth touches the plateau and shows a nominal growth in the range of 1%-2%. Based on the available data, the growth pattern of RMC in different countries:
Growth
Pattern
Countries
Phase (I) Cement consumption
(10%) number of years taken
Phase (II)
Cement consumption
(50%) number of years taken
Phase (III)
Consolidation phase achieved
after number of years

Rapid growth
Greece, Finland, West
Germany, Japan,
Switzerland, 5 to 6 18 to 20
20 to 35

Normal
Growth
Spain, Ireland, Italy,
Austria, Belgium, Great
Britain, Norway,
Sweden, Australia, USA 10 to 11 30 to 35 35 to 40

Slow
Growth
Portugal, France,
Netherlands, Denmark 18 to 20 40 to 45 45 to 50

INDIAN SCENARIO:
The Indian construction industry has been traditionally labour oriented. The pace of mechanization in the past has been very slow due to the availability of cheap labour in abundance, lack of capital investment and the highly fragmented nature of the construction industry. The degree of mechanization is still around 25%-30% while it is well above 70% in most of the developed countries.
The liberalization of Indian economy from 1991 onwards paved the way for large-scale investments in infrastructure, industrial, housing and agriculture sectors. The new age constructions required speed and superior quality to obtain profitable life cycle cost of the projects. The emerging scenario helped to increase the pace of mechanization and facilitated the establishment of RMC plants on commercial scale. RMC in India on commercial scale started in 1993 at Pune with only one plant. It has achieved nearly 15% share of the total concrete produced in the country. In some major cities, like Bangalore, Hyderabad, Mumbai and Chennai the share of RMC has reached as high as 50% to 60%.

Concrete is the largest ‘man made’ material in the world and stands second to water in per capita consumption. Average per capita annual consumption of cement worldwide is about 500 kg against 210 kg in India. Similarly, world over per capita concrete consumption is about 1 ton while it is 500 kg in India. Though cement and concrete consumption is expected to grow at the average rate of 3% to 4% world over, but in India 6% to 8% growth is likely to take place during the next decade. It is therefore very important from life cycle cost, durability and environmental considerations that majority of concrete is produced in centralized RMC plants. The growth prospects of RMC in India in this context looks very bright.

The growth of RMC industry world over has followed ‘S’ curve. The progress during the formative years say up to 10 years is slow, then it follows high growth path for the next 30 to 40 years and again it starts slowing down until it reaches a plateau. In most of the countries, RMC took about 10 to 12 years to consume 10% cement production, while in India commercial RMC is able to consume only about 8.5% of cement production even after 15 years. The growth is very slow from international standards, and main reasons could be identified: (a) VAT/sales tax and excise duty on RMC while no such tax on SMC (b) infrastructure cost in setting up RMC plants is high due to difficulty in getting land at reasonable cost. (c) lack of codal and specifications support (d) more consideration for cost over quality (e) mind-set of people.
RMC PLANT TYPES AND ITS OPERATION:
Following are the different types of ready mix concrete plants and their mixing actions:
Dry batch concrete plant
Wet batch concrete plant
Half-wet batch concrete plant
Combination batch concrete plant
Dry batch concrete plant
A Dry batch Concrete Plant, also known as Transit Mix Plant, weighs sand, gravel and cement in weigh batchers via digital or manual scales. All the ingredients then are discharged into a chute which discharges into a truck. Meanwhile, water is either being weighed or volumetrically metered and discharged through the same charging chute into the mixer truck. These ingredients are then mixed for a minimum of 70 to 100 revolutions during transportation to the jobsite.

Wet batch concrete plant
A Wet batch Concrete Plant, combines some or all of the above ingredients (including water) at a central location into a Concrete Mixer – that is, the concrete is mixed at a single point, and then simply agitated on the way to the jobsite to prevent setting (using agitators or ready mix trucks) or hauled to the jobsite in an open-bodied dump truck.

Types of Wet Batch Mixer and its Mixing Action
Following are the available different types of wet batch mixers and its mixing action:
Rotating Drum Mixer
Rotating drum, freefall mixing action, none tilting.

Rotating drum, freefall mixing action, tilting.

Fixed Trough Mixers
Fixed mixing trough within which spiral blades revolve on horizontal shafts
Fixed mixing trough within which paddles rotate on twin horizontal shafts
Pan Mixers
Fixed horizontal pan in which mixing paddles travel around an annular channel
Fixed horizontal pan in which mixing paddles travel around an annular channel while revolving about their own axis
Fixed horizontal pan in which the mixing blades traverse the entire pan floor with a planetary motion
Fixed horizontal pan in which two sets of mixing paddles travel around an annular channel in opposite directions
Horizontal pan rotating beneath a stationary motor unit carrying paddles, the axes of rotation being non-coincident
Reversing Drum Mixers
System of fixed blades and shovels within a non-tilting rotating drum giving a combined freefall and compulsory mixing action.

Continuous Mixers
Fixed trough mixer with twin rotating shafts and paddles angled at about 20° arranged to produce a continuous mixing action
Half-Wet Batch Ready Mix Concrete Plants
Half wet system includes premixing of sand, cement, and water to make slurry, after that, the slurry and aggregate are added to the truck. Not only does the half-wet system decrease wear and tear on central mixer units but also substantially decline the time of batching.

Combination Batch Ready Mix Concrete Plants
Both dry batch and wet batch system is combined in this type of batching plant, and most of concrete is mixed in dry leg bur small mixers with 0.8-2 m3 is employed to deliver concrete to the customer.

Mobile Batcher Mixer
It is used for intermittent production of concrete at jobsite, or small quantities. Its advantages include combined materials transport and batching and mixing system and requires only one-man operation.

TYPES OF BATCHING EQUIPMENT
Batching equipment is designated as Manual, Semi-Automatic, and Automatic as defined below:
MANUAL
Batching equipment is charged by devices that are actuated manually, with the accuracy of the weighing operation being dependent upon the operator’s visual observation of the scale. The charging device is actuated by either hand or by power assists. The weighing accuracy shall comply with tolerances per Specification.

SEMI AUTOMATIC
Batching equipment is charged by devices, which are separately actuated manually for each material to allow weighing of the material. They are actuated automatically when reaching the designated mass (weight) of each material. The weighing accuracy shall comply with tolerances per Specification.

AUTOMATIC
Batching equipment is charged by devices which when actuated by a single starter switch, will automatically start the weighing operation of all materials consecutively and stop automatically when reaching the designated mass (weight) of each material. Automatic batching equipment shall have suitable delivery interlocks per Specification.

DEVELOPMENT OF RMC PLANTS IN INDIA
Ready-mixed concrete plants arrived in India in the early 1950s, but their use was restricted to only major construction projects such as large dams. Bhakra and Koyna dams were some of the early projects where RMC was used. Later, RMC was also used for other large projects such as construction of long-span bridges, industrial complexes, etc. These were, however, captive plants which formed an integral part of the construction project. RMC in a true commercial sense had yet to arrive in the country.
In the late 1970s, the then Cement Research Institute of India (CRI) – now the National Council for Cement and Building Materials (NCB) – carried out a techno-economic viability study of RMC, to be transported without agitation. In this study, it was observed that the conventional RMC would be uneconomical under the then-prevailing conditions, wherein only small volumes of concrete (1 m3 or less) could be handled at a time, thereby making the transportation cost higher. To reduce the total cost, the study suggested that only a part of the mixing water (about 60 percent) be added at the central plant and such a “semi-dry” mix be transported in non-agitating trucks to the construction site, where the mix could be discharged from the truck to the mixer and remixed with the addition of the balance water. This study further recommended that once the demand for RMC went up, conventional agitator trucks could be introduced, without any change in the central infrastructure. Based on this study, a feasibility report for setting up of RMC plant at Delhi was jointly prepared by the NCB and the Central Public Works Department (CPWD) in 1988.

It was during the 1970s when the Indian construction industry went overseas particularly to the Gulf region, that an awareness of ready-mixed concrete was created among Indian engineers, contractors, builders, etc. Indian contactors in their works abroad began to use RMC plants of 15 m3/hr to 60 m3/hr capacity, and some of these plants were brought to India during the mid – 1980s but used for major construction works. During this period Indian equipment manufacturers had also started manufacturing small RMC plants of maximum capacity of 15 m3/hr. These plants were also used at construction sites.
It was only after cement was fully decontrolled, and particularly since the early 1990s, that RMC has been talked about on a commercial basis. The first plant belonging to Ready-Mix concrete Industries, Pune was set up in 1992. It has its own aggregate quarry. Later in 1994, two RMC plants were set up as dedicated but on commercial terms at Bandra-Kurla Complex in Mumbai, which was followed by another in Navi Mumbai. After this beginning, number of players came forward and set up RMC plants in different parts of the country, mainly in the metropolitan areas. Currently, based on the information obtained from various RMC manufacturers, there are about 2000 commercial plants in existence in the country with a total capacity of 75000m3/hr. The Ready Mix Concrete Manufacture’s Association (RMCMA) was formed in India in 2007 with head quarter in Mumbai. RMCMA is doing very valuable work in the fields of quality assurance and certification of RMC plants of its member companies through Quality Council of India (QCI).
At present nearly 6 million m3 RMC per month (72 million m3 per year) is produced by commercial plants in India. The consumption of concrete in India during the year 2013-2014 is estimated 460 million m3. Though no authentic figures are available, but it can be assumed that nearly 15% to 20% concrete is being used by major mega projects where weigh-batched concrete through dedicated plants is used. The balance about 380 million m3 is used on medium, small and individual house building projects. If we consider the penetration of commercial RMC in this segment, then RMC has a share of about 18% at present. The slow growth pattern model requires 18 to 20 years to achieve 10% cement consumption through RMC route. The actual start of commercial RMC in India can be assumed from 1994 and it has already taken nearly 20 years to achieve 8.5% cement consumption. The growth of RMC industry in last 3 to 4 years has been comparatively slow due to overall depression in GDP and Economic growth in the country, otherwise by now RMC could have achieved 10% consumption of total cement produced in the country.
Table: 2- Commercial- RMC plants in India in the year 2013

Sl. No.
Zone

Provinces /Area
Approximate
Commercial RMC
1 North Himachal, J;K Punjab, Haryana,
Rajasthan, U.P. Delhi, Bihar, Jharkhand, Madhya Pradesh 650
2 West Gujarat, Maharashtra, Goa 480
3

South Andhra, Tamil Nadu, Karnataka, Kerala,
Pondicherry
780
4 East West Bengal, NE States, Chhattisgarh,
Orissa, Sikkim 90
TOTAL 2000
CONCLUSION
Although the ready-mixed concrete industry in India came into being in the late nineties, it has grown steadily and spread its wings into 50 major cities in India in a span of around 15 years. In spite of certain hurdles, the RMC industry is expected to grow further steadily. This optimism is based on the assumption that Indian economy will continue to register a healthy growth rate (i.e. say around 7% in GDP) and that the current emphasis on the development of physical infrastructure and housing will continue. It is to the credit of the RMC industry in India that even when it was in its infancy it successfully implemented a self-regulatory quality framework, which is now being upgraded and brought under the control of an independent multi-stake holder group. The industry has shown encouraging signs in absorbing some latest developments in concrete technology and also in the utilization of industrial wastes such as fly ash and other SCMs.