Understanding Cutting Materials:
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Concrete is a construction material composed of cement as well as other cementitious materials such as slag cement, fly ash, coarse aggregate (such as granite, gravel or limestone), fine aggregate (such as sand), chemical and water admixtures. Concrete is usually used to make pipe, pavements, foundations, highways/raods, bridges, parking structures, architectural structures, brick / block walls, fences, poles, etc.
Type of concrete:
- Green Concrete - The concrete is considered in its "green stage" on 0 to 8 hours after the pour, meaning it has set but has not hardened completely. With green concrete, the sand in the mixture has not bonded to the mortar blend firmly and will cause extreme abrasive action once the physics of cutting begins. Futher, the slurry generated by green concrete is equally as abrasive and will require special undercutting protection for the steel core of the diamond blade. Typically, cutting control joints of highways, industrial floorings, driverways and similar projects is performed during this state. Gila's Green Concrete Blades are perfect for cutting green concrete.
- Cured Concrete -The concrete is considered as "cured stage" on 24 to 72 hours after the pour. The sand is held firmly in the mortar mixture and the overall abrasive actions and properties of the concrete are greatly diminished. Gila's Concrete Blades are perfect for cutting cured concrete.
- Reinforced Concrete - The concrete in which steel reinforcement rebars, plates or fibers have been incorporated to strengthen the material that would otherwise be brittle. Reinforced concrete is currently widely used for commerical/industrial buildings and other structures such as bridges, fundations, etc. Gila's Concrete Turbo Blades and Professional Concrete Blades are perfect for cutting reinforced concrete.
- Prestressed Concrete - The concrete in which high tensile steel cable or rebars are heavily used to provide a clamping load which produces a compressive stress that offsets the tensile stress that the concrete compression member would otherwise experience due to a bending load. Gila's Professional Concrete Blades are perfect for cutting prestressed concrete.
Hardness of Concrete:
Compressive Strength - The hardness of concrete is referenced by its compressive strength measured in Pounds per Square Inch (PSI). Cured concrete slabs vary widely in compressive strength with temperature, moisture, design of mixture additives, cementitious materials and curing processes often determining their measured level of strength. The higher the compressive strength, the harder the material.
- Soft - 3,000 or less PSI (material like parking lots)
- Medium - 4,000 to 6,000 PSI (material like roads)
- Hard - 5,000 to 8,000 PSI (material like bridges)
- Very Hard - 8,000 or more PSI (material like nuclear structures)
Steel Reinforcement - It costs more to cut concrete that contains reinforced steel rebars because cutting rates are slower and blade life is reduced. If the cross-sectional area of concrete contains 1% of steel rebars, it will reduced the blade life at 20% to 30% than if no steel reinforcement are present. If the cross-sectional area of concrete contains 3% of steel rebars, it will reduced the blade life as much as 80%. The rebar's size is another big factor that can significantly reduce the blade life.
- Heavy Reinforcement - Which the concrete contains single mat of #5 rebars per foot on center or double mats of #4 rebars per foot on center.
- Medium Reinforcement - Which the concrete contains #4 rebars per foot on center or multi-mat wire mesh.
- Light Reinforcement - Which the concrete contains wire mesh or single mat.
Heavy rebar can also result from different grades od steel. Typical rebar is grade 40 steel. Grade 60 steel would make the example of #4 medium rebar, above, into a heavy rebar. Rebar gauges are in eights of an inch - #4 rebar is 1/2" diameter, #5 is 5/8". Where rebar specifications do not exist on road, pull a core sample before buying a right blade.
Aggregates Mixtures - Aggregates can be naturally occurring minerals, gravel, sand and crushed stone. The most desirable aggregates used in concrete are triangular or square in shape and with hard, dense, well graded and durable properties. The average size and composition of aggregates greatly influence the cutting characteristics and selection of the diamond blade. Large aggregates size between 3/4" to 1-1/2" or bigger tend to cause blade to cut slower, but blade life will longer. Aggregates size smaller than 3/8" allow the blade to cut faster, but blade life will be shorter. Aggregate hardness is referenced by the Mohs Scale. Thes scale assigns arbitrary quantitative units, ranging from 1 to 10, by which the scratch hardness of a mineral is determined. Each unit of hardness ir represented by mineral that can scratch any other mineral having a lower ranking number. The minerals are ranked from talc (#1-the softest) to diamond (#10-the hardest).
Asphalt is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums. It is most commonly modelled as a colloid with asphaltenes as the dispersed phase and maltenes as the continuous phase. The primary use of asphalt is in road construction, where it is used as the glue or binder for the aggregate particles, and the road surfacing material is usually called asphalt overlay concrete. Asphalt does not cure in the sense that concrete does, and once spread and rolled, it can be cut or drill almost immediately. Unlike cured concrete, sand in asphalt never bonds as firmly and the slurry created when cutting will be extremely abrasive. A bond matrix similar to cutting green concrete and undercutting protection are very important factors when undertaking asphalt cutting operations. There are several factors should be observed when cutting asphalt.
- Total asphalt depth can very. It is common to cut through the asphalt layer into the sub-base. Generally, the sub-base contains a high content of very abrasive materials such as sand, dusts, dirt and similar materials. This undesirable situation causes rapid wear of the diamond blade.
- If the sub-base contains higher ratio of sand, then the diamond blade will cut faster, but total footage may decrease.
- If the asphalt contains a high ratio of hard and large sized aggregates, it will cause the diamond blade to cut slower.
- To cut broken-up asphalt, it often attract dusts and sand fillers within the cracks. This will make the asphalt more abrasive and affect the life of the diamond blade.
Type of Undercut Protection:
- Drop Segment Undercut Protection - Gila's Premium Asphalt Blade has this style of undercut protection with tough wear resistant bonds for good cutting performance and great blade life. This blade is usually designed for use on under 20 HP walk behind saw and gas cut off saw.
- Slant Segment Undercut Protection - Gila's Supreme Asphalt Blade has this style of undercut protection with tough wear resistant bonds and higher diamond concentration for even better cutting performance and longer blade life. This blade is usually designed for use on 20 to 35 HP walk behind saw.
- Tri-Plex Undercut Protection - Gila's Professional Asphalt Blade has carbide-tip inserts on each segment with slant drop segments for maximum undercut protection, great cutting performance and superior blade life. This blade is usually designed for use on up to 60 HP walk behind saw.
The common materials of masonry construction are brick, concrete block and natural stone such as granite, marble, travertine or limestone, etc. Masonry is generally a highly durable form of construction and it is commonly used for the walls of buildings, retaining walls and monuments. Brick and concrete block are the most common types of masonry in use in industrialized nations and may be either weight-bearing.
Brick - is a block of ceramic material used in masonry construction, usually laid using mortar. Bricks may be made from concrete, clay, shale, calcium silicate, soft slate or shaped from quarried stone. Clay is the most common material, with modern clay bricks formed in one of three processes - soft mud, dry press, or extruded.
• Soft Mud Bricks - It starts with the raw clay, preferably in a mix with 25-30% sand to reduce shrinkage. The clay is first ground and mixed with water to the desired consistency. The clay is then pressed into steel moulds with a hydraulic press. The shaped clay is then fired at 900 to 1000 degree to achieve strength.
• Dry Pressed Bricks - It is similar to soft mud brick but starts with a much thicker clay mix, so it forms more accurate, sharper-edged bricks.
• Extruded Bricks - It starts with the clay is mixed with 10 -15% water (stiff extrusion) or 20-25% water (soft extrusion). This is forced through a die to create a long cable of material of the proper width and depth. It then cut into bricks of the desired length by a wall of wires. Most building structural bricks are made by this method, as hard dense bricks result.
Hardness of Bricks - There are many different types of bricks and different scales of hardness. The strength of a unit is used to determine its durability and cutability. Both compressive strength and absorption are affected by properties of the clay and method of manufacturing and degree of fired. Most bricks have a strength ranging from 3,000 PSI to over 20,000 PSI with the average being around 10,000 PSI. Also different type, size and volume of aggregates in the mixture can further strengthen the hardness of the bricks.
Fire Brick or Refractory Brick - It starts with the fireclay is baked in the kiln until it is partly vitrified and for special purpose may also be glazed. Fire bricks usually contain 30-40% of aluminium oxide or alumina and 50-80% of silicon dioxide or silica. They can also be made of chamotte and other materials. For bricks of extrem refractory character, the aluminum oxide content can be as high as 50-80% and silicon carbide may be present. The silica firebricks that line steel-making furnaces are used at temperatures up to 1650 degree which would melt many other types of ceramic and in fact part of the silica firebrick liquefies.
Concrete Block - In the United States, concrete block, cement block or foundation block are generically known as Concrete Masonry Units (CMU). Concrete blocks are made from cast concrete, cement and aggregate (usually sand) and fine gravel for high-density blocks. Lower density blocks may use industrial wastes as an aggregate. Those that use cinders such as fly ash or bottom ash are called cinder blocks. Clinker blocks are use clinker as aggregate. Lightweight blocks can also be produced using aerated concrete. Furthermore, cinder and concrete blocks typically have much lower water absorption rates than brick. They often are used as the structural core for veneered brick masonry, or are used alone for the walls of garages, factories and other industrial style buildings. Concrete blocks may be produced with hollow centres to reduce weight or improve insulation. Concrete block, when reinforced with concrete columns and tie beams or steel rebars, is a very common building material for load-bearing walls of buildings, in what is termed Concrete Block Structural (CBS) construction.
Stone Masonrys - Stone blocks used in masonry can be dressed or rough. Stone masonry utilizing dressed stones is known as ashlar masonry, where as masonry using irregularly shaped stones is known as rubble masonry. Both Rubble and ashlar masonry can be laid in courses through the careful selection or cutting of stones. Natural stone venners over CMU or tilt-up concrete walls are widely used to give the appearance of stone masonry. Sometimes river rock is used as veneer. This type of material is not favored for solid masonry as it requires a great amount of mortar and can lack intrinsic structural strength. Manufactured stone (cultured stone) veneers are became more popular than the natural stones and are typically made from concrete.
Natural stone is a geographical list of stone used for decorative purposes in construction and monumental sculpture. Natural and precast stones vary significantly in their geographic origin, mineralogical composition, and physical and mechanical properties. There are numerous types of stone to select, with each one exhibiting specific qualities of compressive strength and abrasive resistance.
Granite - is a common and widely occurring type of intrusive, felsic, igneous rock. granite usually have a medium to coarse granited texture. A granitic rock with a porphyritic texture is sometimes known as a porphyry. Granite can be pink to dark gary or even black, depending on their chemistry and mineralogy. Outcrops of granite tend to form tors and rounded massifs. Granite sometimes occur in circular depressions surrounded by a range of hills, formed by the metamorphic aureole. Granite is nearly always massive, hard and tough, and therefore it has gained widespread use as a construction stone.
Marble - is a non foliated metamorphic rock resulting from the metamorphism of limestone, composed mostly of calcite. It is extensively used for sculpture as a building material, and in many other applications.
Limestone - is a sedimentary rock composed largely of the mineral calcite. Like most other sedimentary rocks, limestones are comprised of grains, however, around 75%-90% of limestone grains are skeletal fragments of marine organisms such as coral or foraminifera. Other carbonate grains comprising limestones are ooids, peloids, intraclasts and extraclasts and extraclasts. Limestone males up about 10% of the total volume of all sedimentary rocks. limestone may also form in both lacustrine and evaporite depositional environments.
Sandstone - is a sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow, red, gray and white. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions. Some sandstones are resistant to weathering, yet are easy to work. This makes sandstone a common building and paving material. Because of the hardness of the individual grains, uniformity of grain size and friability of their structure, some types of sandstone are excellent materials from which make grindstones for sharpening blades and other implements.
Travertine - is a banded, compact variety of limestone formed along streams, particularly where there are waterfalls and around hot or cold springs. Calcium carbonate is deposited where evaporation of the water leaves a solution that is supersaturated with chemical constituents of calcite.Tufa, a porous or cellular variety of travertine, is found near waterfalls. Coquina is a poorly consolidated limestone composed of pieces of coral or shells.
Slate - is a fine grained, foliated, homogeneous metamorphic rock derived from an original shale type sedimentary rock composed of clay or volcanic ash through low grade regional metamorphism. The result is a foliated rock in which the foliation may not correspond to the original sedimentary layering. Slate is frequently grey in color especially when seen en mass covering roofs.
General Characteristics of Stone - The complex nature and variables of natural and precast stone make it difficult to generalize their overall physical and mechanical properties. Unless the operator has the experience in cutting a particular kind of stone, there are methods that can help predict the stone's cutting performance and determine the best selection of diamond blade. The American Society of Testing and Materials (ASTM) recognize several physical property measurments that can be very helpful to identify a stone's hardness.
- Cerchar Abrasive Index (CAI) - Measuring a rock's abrasive for determining cutting wear rates. Defined by a graduated numerical scale: lower numbers indicating less abrasive qualities and therefore greater hardness.
- Uniaxial Compressive Strength (UCS) - Measuring basic rock strength parameters. Commonly measured in Pounds Per Square Inch (PSI).
- Shore Scleroscope Hardness Test - A dynamic indentation hardness test a number to indicate the height of a rebounding hammer off the surface of the material. The higher the number the harder the material.
- Mohs Hardness Scale - A scale of hardness applied to minerals ranges from 1(talc) to 10 (diamond) and comparatively indicates a mineral's scratch potential. The higher the number the harder the mineral.
Ceramic Tile - Ceramic tile is a mixture of clays which have been shaped and fired at high temperatures, resulting in a hard body. This hard body may then be left untreated or colored glass coating.
Hardness of Ceramic Tile - The percentage of water absorption by the tile body determines whether the ceramic tile is impervious, vitreous, semi-vitreous, or non-vitreous. From impervious, where absorption rates of 15% and higher, hardness factors change. Most glazes fall in the 5 to 6 Mohs Scale range. However, certain types of floor and porcelain tiles can have compressive strengths of 10,000 PSI and a Mohs hardness factor of 8.
Porcelain Tile - Porcelian tile is ceramic tile with a water absorption rate of less than 0.5 percent that are used to cover floors and walls. Thay can either be unglazed or glazed.
Hardness of Porcelian Tile - The tile is rated from 0 to 5 according to the ASTM C1027 ( or ISO 10545-7) test for surface abrasion of glazed tile. This rating determines the tiles suitability for various end use conditions.
Glass tiles and glass mosaics are pieces of glass formed into shapes with unique depth and color. Cutting glass tiles can be complex for the installer because glass tiles are more rigid and fragile than ceramic or porcelain tiles, chipping or cracking occurs when too much pressure is applied. Whether the glass is clear, has color throughout the glass, or has color painted on the back, correctly cutting the glass will help prevent chips and cracks in the glass edge and surface. The best way to cut glass tiles and mosaics is using a wet saw with the correct diamond blade. The method for cutting glass with a diamond blade is similar to cutting ceramic or porcelain tile. However, cutting coarser materials like ceramic, porcelain, granite or marble usually requires a diamond blade with large grit of average standard quality diamonds (see Figure1). Cutting glass tile requires a diamond blade with high concentration of small grit of high standard quality diamonds (see Figure2) for a smooth and clean cut. Therefore, you cannot use a diamond blade designed for ceramic or porcelain tile to cut glass tiles or glass mosaics, because the larger diamond will rip and chip the edges, no matter how carefully you work.
Instructions on how to cutting glass tiles / mosaic with a wet tile saw:
Step1 - Ensure the glass tile blade is secured on the wet saw properly.
Step2 - Ensure the water is coming out from the water sprayer or reservoir.
Step3 - To prevent back layer chipping, back side should be facing up.
Step4 - When cutting, be sure to press the glass tile/mosaic slowly, lightly and steadily.
Step5 - Allow the diamond blade to do the work.
Step6 - Avoid adding stress to the last portion of the cut by cutting slowly.