The GRC Glossary

Aggregate/Cement Ratio

The aggregate/cement ratio refers to the proportion between the total mass of dry aggregate and the mass of dry cement in a Glass Fibre Reinforced Concrete (GRC) mixture. This ratio plays a crucial role in determining the strength, workability, and other properties of the GRC mixture.

AR Glass Fibres

AR (Alkali Resistant) Glass Fibres are specially engineered glass fibres designed to withstand the highly alkaline environment present in concrete mixtures. These fibres are manufactured with a minimum zirconium dioxide content of 16%, providing them with exceptional resistance to the corrosive effects of alkalis present in cementitious materials. Due to their high alkali resistance, AR glass fibres maintain their structural integrity over time, enhancing the durability and longevity of concrete structures in which they are used.

Automated Water Meter

Power-Sprays’ Automated Water Metering systems are essential equipment for Glass Reinforced Concrete (GRC) production, ensuring accurate water dispensing. They offer both manual and automatic modes: in manual mode, operators control water dispensing with a push of a button, while automatic mode allows for preset water volumes, dispensing precise amounts as needed. Integrating these systems improves production efficiency and product consistency, enhancing overall quality and workflow reliability.

‘Bag & Bucket’ Tests

Calibration methods for GRC spray equipment, involving measuring material output from a bag or bucket. This ensures consistent and accurate dispensing during spraying operations, maintaining equipment performance.

Bucket Trolley

A Power-Sprays Bucket Trolley serves as a practical solution for transporting materials from the mixer to a mould or GRC Spray Station. This versatile trolley eliminates the need for additional moving equipment, providing a convenient and efficient means of transferring mixed materials with ease and precision. Its sturdy construction and ergonomic design ensure seamless movement, enhancing workflow productivity in GRC production processes.

Chopped Fibre

In premix GRC, chopped fibres are an essential component sourced pre-chopped in bags. These fibres, usually made of glass or synthetic materials, are cut into precise lengths before being added to the GRC mix. This process ensures uniform distribution and reinforcement throughout the material, enhancing its strength and durability.

Chopped Fibre Dispenser

The chopped fibre dispenser is a precision tool designed to accurately dispense pre-cut glass and synthetic fibres, revolutionising the process of GRC production. By ensuring precise measurements and uniform distribution of fibres, this equipment enhances the consistency and quality of GRC mixes. Its advanced functionality streamlines the production process, allowing for greater efficiency and reliability in achieving desired structural and aesthetic properties in GRC components.

Compact Batching Plant

Power-Sprays’ Compact Batching Plants epitomise efficiency in Glass Reinforced Concrete (GRC) production. Meticulously crafted, these bespoke plants integrate cutting-edge glass fibre technologies, revolutionising the manufacturing process. Tailored to exact specifications, they ensure seamless and optimised production, marking a significant advancement in GRC manufacturing capabilities.

Concentric Spray Gun/Head

The Power-Sprays Concentric Spray Head represents a breakthrough in GRC application technology. Engineered for optimal efficiency, this innovative spray gun is seamlessly integrated with an enhanced boom, specifically designed for Power-Sprays Spray Stations. Together, they redefine the standards of precision and effectiveness in GRC spraying applications.

Coupons

Coupons refer to a specific number of specimens extracted from a test board, primarily intended for evaluating and quantifying particular properties. These samples are carefully selected to represent the overall characteristics and performance of the tested material or structure.

Crane Mounted Bucket Lifter

The Power-Sprays Crane Mounted Bucket Lifter offers a hassle-free solution for transporting heavy GRC mixes. Engineered for swift attachment to cranes, this equipment facilitates efficient handling of materials, ensuring seamless integration into production processes.

Depth Gauge

A depth gauge is a crucial tool for measuring the depth of set GRC, facilitating the creation of consistent and uniform thickness to meet specific requirements. By providing precise depth measurements, it ensures accurate formation and enhances the quality of GRC applications.

Dry Curing

A method of curing which prevents early loss of moisture and allows curing to take place without keeping the GRC damp. Dry curing is carried out by adding an appropriate quantity of the polymer into the GRC mix.

Electric Glass Fibre Chopper

For manufacturers looking to purchase their glass fibres in rovings as opposed to chopped strands, this machine is recommended. The Electric Glass Fibre Chopper efficiently produces chopped fibre lengths ranging from 6mm to 25mm and is controlled by an incremental timer, eliminating the need to weight the chopped fibre.

Extremes of Dimensional Variations

Extremes of dimensional variations refer to the maximum changes in dimensions, including residual hydraulic shrinkage and reversible expansion, observed in a GRC composition due to fluctuations in water content. These variations are important considerations for products exposed to environmental elements.

Facing Coat

A facing coat is the initial layer applied in GRC production, typically devoid of fibres but enriched with decorative sands, aggregates, and pigments. It serves as a foundation for subsequent layers, enhancing the aesthetic appeal of the final product.

Fleximould

Fleximoulds are rubber moulds used for casting concrete, GRC, or gypsum. Moulds can be formed into all manners of complex shapes and due to their dimensional stability, they are able to withstand the daily rigours of casting, demoulding, and handling without damage.

Flexural Test

The 4-point flexural test is the most important test for GRC. Using a dual-column, bench mounted Flexural Testing Machine with full computer control and a precision AC servo drive system, the strength of GRC coupons can be efficiently tested.

Forklift Mounted Bucket Lifter

The forklift mounted bucket lifter by Power-Sprays is engineered to facilitate the lifting and transportation of heavy buckets filled with GRC mix. This innovative solution enhances convenience and efficiency in GRC production processes.

GRC/GFRC

Glass Fibre Reinforced Concrete (GRC) is a composite material composed of a cementitious matrix reinforced with fine glass fibres. This innovative material combines the strength and durability of concrete with the flexibility and lightweight properties of glass fibres. GRC offers architects and engineers a versatile solution for creating intricate architectural elements, facades, and structural components with exceptional strength and aesthetic appeal.

Glass Fibre Content by Weight (WF)

Glass fibre content by weight (WF) denotes the percentage ratio of glass fibre mass to the total mass of GRC in its uncured (wet mix) state. This parameter influences the structural strength and performance of the final GRC product.

GRC125 Combination Mixer

Our revolutionary GRC Mixer, offering the unique ability to produce both spray grade slurry and premix without any compromise. Boasting a 65-litre capacity, the mixer perfectly accommodates up to 125kg of materials.

High Shear Mixer

A High Shear Mixer is a specialised piece of equipment crucial for GRC production, specifically designed to prepare fine sand/cement slurries required for the spray process. With its high shear action, this mixer ensures thorough blending, resulting in homogeneous and fluid mixtures suitable for spraying applications.

Limit of Proportionality (LOP)

The limit of proportionality, also referred to as the elastic limit, denotes a critical point in a flexural bending test where the stress/strain plot diverges from a linear trajectory. This signifies the threshold at which the material’s elastic behaviour transitions into plastic deformation. In practical terms, it represents the maximum stress level that a material can endure without undergoing permanent deformation. Beyond this limit, the material exhibits non-linear behaviour, indicating the onset of irreversible changes in its structural integrity.

LW Combination Spray Gun

The Lightweight (LW) Combination Spray Gun is engineered to produce a precise and focused spray pattern, making it ideal for applications requiring accuracy and control. Featuring quick release fittings, this spray gun facilitates swift and effortless cleaning and maintenance procedures. Its lightweight design enhances manoeuvrability and reduces operator fatigue, ensuring optimal performance and efficiency in spray operations.

LW Facing Coat Spray Gun

The LW Facing Coat Spray Gun is an essential tool for the smooth application of the initial, non-reinforced surface layer, also known as the mist coat, in Glass Fibre Reinforced Concrete (GRC) production. This spray gun is designed to provide precise and uniform coverage of the facing coat, ensuring a flawless finish on GRC surfaces. Its lightweight construction and ergonomic design make it easy to handle, facilitating efficient spraying operations for enhanced productivity.

MFFT

The Minimum Film Formation Temperature (MFFT) refers to the lowest temperature at which an acrylic polymer can form a continuous film. In the context of GRC production, MFFT is a critical parameter for acrylic polymers used in coatings and binders. Understanding the MFFT allows manufacturers to optimize application conditions, ensuring proper film formation and adhesion, particularly in colder environments.

Mist Coat

A mist coat is the initial cementitious sprayed coating applied in Glass Fibre Reinforced Concrete (GRC) production before the incorporation of glass fibres. This thin layer serves as the foundation for subsequent layers of GRC, providing a smooth and uniform surface for optimal adhesion and structural integrity. The mist coat is essential for ensuring proper bonding between the GRC matrix and the reinforcing fibres, ultimately contributing to the strength and durability of the finished GRC product.

MK3 Powertex Facing Coat Spray Gun

The MK3 Powertex Facing Coat Spray Gun is one of our top-selling products. It’s ideal for quick and cost-effective application of surface finishes and “mist” coats in GRC production. Its ergonomic design and advanced features ensure swift and precise application, making it a popular choice among GRC manufacturers.

MK5A Premix Spray Gun

The MK5A Premix Spray Gun is a lightweight and user-friendly handheld unit ideal for spraying premix Glass Fiber Reinforced Concrete (GRC/GFRC). Its simple design and reliable performance make it a preferred choice for achieving uniform surface finishes in GRC/GFRC production.

Modulus of Rupture (MOR)

The Modulus of Rupture (MOR) represents the highest stress level observed on a stress/strain plot during a flexural bending test. This crucial measurement provides insight into the maximum stress a material can withstand before fracturing or breaking. In the context of Glass Fibre Reinforced Concrete (GRC) production, MOR serves as a key indicator of the material’s structural integrity and load-bearing capacity. By assessing MOR, manufacturers can ensure the quality and durability of GRC products for various construction applications.

Pneumatic Bucket Lifter

The Power-Sprays Pneumatic Bucket Lifter is a specialised lifting device engineered to safely and efficiently handle heavy GRC mixes. Utilising pneumatic power, this innovative lifter alleviates the need for manual lifting, reducing strain on operators and ensuring workplace safety. By seamlessly integrating into GRC production processes, the pneumatic bucket lifter enhances productivity and ergonomics, making material handling tasks more manageable and efficient.

Polymer-Modified GRC

Polymer-modified GRC, also known as polymer-modified GFRC, refers to Glass Fibre Reinforced Concrete or Glass Fibre Reinforced Cement that has been enhanced through the addition of an acrylic thermoplastic polymer dispersion. This modification serves multiple purposes, including facilitating dry curing and improving various properties of the composite material. By incorporating polymer additives, polymer-modified GRC achieves enhanced durability, flexibility, and resistance to environmental factors, making it a versatile and reliable choice for a wide range of construction applications.

Power-Sprays

Established in 1962, Power-Sprays Ltd. has been a pioneer in the manufacturing of specialist equipment for mixing, pumping, and spraying cementitious composites for over 60 years.

Our journey began with the development of equipment for the spray application of decorative coatings, veneer plasters, and fire protection coatings. As the industry evolved, particularly in the 1970s, we shifted our focus towards developing machinery for the emerging Glass Fibre Reinforced Concrete (GRC/GFRC) sector, which was then in its infancy. Since then, our commitment to innovation and quality has propelled us to become a global leader in GRC/GFRC production technologies.

Today, our equipment is trusted by manufacturers in over 100 countries worldwide.

Premix GRC

Premix GRC, or premix Glass Fibre Reinforced Concrete, is a manufacturing method where pre-cut alkali-resistant (AR) glass fibres and cementitious slurry are thoroughly mixed during the production process. This process involves combining the dry ingredients, including cement, aggregates, and any additives, with water to form a slurry. The pre-cut AR glass fibres are then added to the slurry mixture, ensuring uniform distribution and consistent reinforcement throughout. Premix GRC offers advantages in terms of convenience, efficiency, and control over fibre distribution, resulting in high-quality GRC products suitable for various construction applications.

Premix Mixer

A Premix Mixer is a specialised two-stage or variable speed mixer designed for preparing fine sand/cement slurries and blending chopped AR glass fibres in the premix process of Glass Fibre Reinforced Concrete (GRC) production.

PS10000i

The PS10000i is a powerful GRC/GFRC pump spray station, designed as an upgrade to the popular PS9000i. With a larger rotor/stator pump assembly, it ensures longer life and minimal downtime, ideal for high-output production. Featuring an easily manoeuvrable design, it includes a low-level, extra-long material hopper for convenient loading. The twin-section electric/pneumatic control panel is positioned at a convenient height for easy access, while waterproof cabinet housing (IP66 rated) protects all essential components.

PS38i

The PS38i Spray Station is another of Power-Sprays’ robust Spray Stations. This machine is built with reliable 38mm peristaltic pumps driven by powerful 3-phase electric motors and frequency inverter speed controllers. With no moving parts in contact with materials, it can handle various mixes, making it ideal for Traditional Hand Spray and Spray Premix GRC/GFRC production.

PS9000i

The PS9000i is Power-Sprays’ flagship GRC/GFRC pump spray station, renowned for its popularity, reliability, and user-friendly design. With easy manoeuvrability, a low-level material hopper, and a twin-section electric/pneumatic control panel, it offers convenient operation. All essential components are housed in a waterproof cabinet for protection.

Rovings

Rovings are rolls of un-chopped glass fibres. These are essential for applications like traditional hand spray GRC where rovings and slurry are simultaneously fed through machinery and sprayed at the same time.

Simultaneous Sprayed GRC

Simultaneous Sprayed GRC is a manufacturing method where GRC is produced by spraying cementitious slurry and chopped AR glass fibre simultaneously. This ensures uniform dispersion of reinforcement for enhanced structural integrity.

Slump Test

A Slump Test is a procedure used to measure the consistency of a cementitious slurry, typically used in the production of concrete and GRC (Glass Reinforced Concrete). During the test, a sample of the slurry is placed into a cone-shaped mould and then carefully removed, allowing the slurry to settle. The amount of settlement, or “slump,” is then measured, providing an indication of the workability and flow characteristics of the slurry. This test helps ensure that the slurry has the appropriate consistency for the intended application, such as spraying, casting, or moulding.

Spring Compaction Rollers

Spring Compaction Rollers are essential tools used in GRC production processes. They come in various types tailored for specific applications within the production line. These rollers are primarily designed to spread out and flatten GRC mixtures, ensuring uniformity and eliminating air voids within the material. By applying pressure evenly across the surface, spring compaction rollers aid in achieving desired compaction levels, enhancing the overall quality and integrity of GRC components.

Test Board

A test board refers to a sheet of Glass Reinforced Concrete (GRC) produced during the manufacturing process specifically for quality assessment purposes. These boards serve as specimens for evaluating the quality and performance of GRC products being manufactured. It is crucial that test boards are fabricated in the same manner and concurrently with the actual GRC products to ensure they accurately represent the quality of the material. By examining properties such as strength, texture, and appearance, test boards help manufacturers maintain consistent standards and identify any potential issues during production.

Test Board Mean

The Test Board Mean is the average value calculated from individual test coupon results on a single test board. This provides a representative assessment of GRC properties for statistical analysis.

Top/Bottom Ratio

The Top/Bottom Ratio is the comparison between Modulus of Rupture (MOR) results of GRC samples tested with the mould face and trowelled face in tension, indicating relative strength variations between surface orientations.

Truck Mounted Fibre Chopper

For integrating GRC into volumetric mixers, Power-Sprays offers a Truck Mounted Fibre Chopper. The truck-mounted fibre chopper automates the cutting of glass fibres and facilitates their direct feeding into the mixing auger of the volumetric mixer. This integration ensures accurate dosing and uniform distribution of fibres within the GRC mix, enhancing the overall quality and consistency of the final product. By enabling efficient and precise fibre management, the truck-mounted fibre chopper streamlines GRC production workflows, improving operational efficiency and product reliability.

Uncured State

In the manufacturing process of Glass Reinforced Concrete (GRC), the ‘uncured state’ refers to a stage where all physical processes altering the material’s composition have concluded. However, the glass fibre can still be separated from the matrix through the action of running water. At this stage, the GRC mixture has achieved its desired consistency and is ready for further processing, such as moulding or spraying, to shape the final product.

WAAPS 3000 Dispensing System

The Power-Sprays Water, Polymer, and Admixture dispensing system, abbreviated as WAAPS 3000, is a precision equipment used in Glass Reinforced Concrete (GRC) production. It enables accurate dispensing of liquids crucial for GRC formulation, including water, polymer, and admixtures, with simple operation facilitated by the push-button mechanism. The system’s programmable feature allows for the storage and recall of up to 30 different recipes, ensuring consistency and efficiency in GRC manufacturing processes.

Washout Test

A Wash-Out Test is used to determine the glass-fibre content, by weight, of sprayed GRC. A sample of GRC is placed in a mesh basket, worked under running water to separate the fibre from the matrix, then dried in a laboratory oven. By recording the masses of the basket, and the basket and its contents at each stage, the glass-fibre content can then be calculated.

Water/Cement Ratio

In Glass Reinforced Concrete (GRC) production, the water/cement ratio refers to the proportion between the mass of total water and the mass of dry cement in the uncured state of the GRC mixture. This ratio is crucial in determining the workability, strength, and other properties of the GRC mix. When pozzolanic fillers such as fly ash, silica fume, and metakaolin are utilized, they can be considered as part of the binder content. In such cases, the water/cement ratio is expressed as a water/total binder ratio, accounting for both cement and pozzolanic fillers.