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Field observations from precast manufacturers in India and overseas show that wet-cast production can be scaled without proportionately increasing labour - when batching, material control and workflow design are treated as one system.

Over the past two years, the Atlantic Polymers team has been in close contact with leading manufacturers of precast concrete products across India and international markets. We studied not only mould performance, but also how concrete was batched, how vibration was managed, how moulds moved through the factory, how curing and demoulding were organised, and where productivity or quality was being lost.

Across geographies and plant sizes, one concern appeared repeatedly: wet-cast paver production using rubberised PVC moulds and vibro-forming technology was still viewed as a labour-dependent process that was difficult to scale. The limitation, however, was often not the wet-cast method itself, but the way production had evolved as a collection of manual activities rather than an integrated system.

The productivity challenge

From our field interactions, a typical manufacturer following conventional wet-cast practices produces roughly 150-200 sq m per day and may deploy 20-30 workers across batching, filling, vibration, movement, curing and demoulding. Some manufacturers produce around 2,000 sq m per day, but many do so by adding labour in broadly the same proportion. This becomes difficult to manage when labour availability, attendance, training and supervision are uncertain.

This has encouraged many producers to consider dry-cast technology, which can produce approximately 500-1,000 sq m per day, or more depending on the investment and configuration. Dry-cast is an important technological option. Yet wet-cast remains valued for design flexibility, surface finish, colour possibilities and specialised products. The more relevant question is therefore not simply, ‘wet-cast or dry-cast?’ but, ‘how can wet-cast become more process-driven?’

Three linked constraints

The first is labour dependence. Manual batching, material movement and inconsistent operating practices restrict output and make performance dependent on individual operators.

The second is mix design and water-cement ratio. Several manufacturers told us that they could not reduce the water-cement ratio adequately without affecting workability. This can limit strength and increase cement consumption. The solution lies in validating grading, proportioning, water control, suitable admixtures or hardeners, vibration parameters and curing as one complete process.

The third is aggregate variability. Changes in sand, crusher dust and stone grading affect workability, compaction, finish and strength. Quarry shutdowns, strikes and changes in aggregate policy can also interrupt supply. A producer may therefore follow the same nominal recipe but obtain a different result from one batch to another. In a highly price-competitive market, this directly affects margins and customer confidence.

A practical case: four-fold output with fewer people

To explore what was possible, we worked closely with a customer who was equally committed to redesigning the process. A batching plant was integrated with the vibration tables and material flow was reorganised to reduce manual handling and waiting time.

According to production data shared by the customer, the plant increased output approximately four-fold and is now capable of producing close to 700 sq m per day with 11 workers in the main production operation. Demoulding is handled separately on a contract basis. More important than the headline capacity is the consistency achieved through repeatable batching, better input control and a defined operating sequence.

The customer also began using processed sand generated from his own stone-crushing operations, reducing dependence on externally sourced sand and improving control over grading and supply. He reports an approximately 11% reduction in cement consumption and 5% reduction in pigment consumption while maintaining the required product quality. These results are specific to that plant, its inputs and operating discipline, but they demonstrate the opportunity available through process engineering.

The mould is part of the production system

A rubberised PVC mould cannot be evaluated separately from the concrete placed in it or the environment in which it is used. Mould flexibility, product geometry, mix workability, vibration, curing temperature and demoulding timing influence one another. The industry must therefore move beyond evaluating moulds only by purchase price or expected cycles and consider total production economics: output per shift, labour per square metre, rejection, consistency, cement and pigment usage, and the ability to reproduce quality across batches.

Building a knowledge-sharing platform

Our most important learning is that many solutions already exist within the industry, but the knowledge remains fragmented. Machine manufacturers understand automation; material suppliers understand mix behaviour; quarry owners understand aggregates; mould manufacturers understand geometry and demoulding; and producers understand the factory floor. What is often missing is a forum where this knowledge can be combined and tested.

Atlantic Polymers is therefore developing the Atlantic Polymers Precast Academy, a knowledge-sharing initiative for customers and industry stakeholders. It will document operating practices, discuss region-specific challenges, connect equipment, material and process specialists, and develop case studies based on measurable results. The objective is not to prescribe one machine, mix or method, but to help manufacturers identify bottlenecks and make informed improvements.

Wet-cast paver production need not remain an unorganised, labour-led activity. With controlled batching, stable raw materials, appropriate moulds, disciplined curing and demoulding, and shared technical knowledge, it can become a scalable and professionally managed manufacturing process. The next advance may come not from a single product, but from connecting knowledge across the value chain and converting it into a repeatable system.

Author note: Naren Thakkar is Director of Atlantic Polymers Pvt Ltd, a manufacturer and exporter of rubberised PVC moulds for wet-cast precast concrete applications.