Hanson Premix. Premix mortars

Transcription

1 Hanson Premix Premix mortars

2 Hanson Premix is one of the UK s most popular and enduring ready-mixed concrete and mortar brands with a reputation built on over 50 years of quality and service. Our top quality mortars are delivered readyto-use in our distinctive blue, red and grey vehicles from a network of 40 plants strategically located throughout the UK. Premix mortars

3 Quality-controlled batching ensures consistent colour and strength and our mortars remain usable for up to two working days when stored in the covered tubs. Plastic tubs are provided for delivery to allow the material to be moved easily around sites by forklift or crane. Using Premix mortars makes good economic sense for projects of all sizes. You can save on the costs of mixing equipment and labour, eliminate messy site mixing and avoid the loss of sand and cement through wastage or theft. Premix mortars are manufactured with high quality sands, cements and admixtures to meet the requirements of BS EN Prepared under strictly controlled conditions, each batch is consistent in colour, workability and strength. In addition, construction can start before water and electricity services are installed and site clearance is also made easier. It s the simplest way of ensuring top quality mortars are available when you need them, with no expensive set-up costs. A comprehensive range Our plants can produce mortars for all types of masonry construction, including lime sand mortar for natural stonework. They are recommended for use with a wide variety of dense aggregate or lightweight concrete blocks, facing units and bricks including the extensive London, Kempston and Butterley brick ranges from Hanson Building Products. When used in properly constructed masonry, Premix mortars set in the same way as site-mixed mortars and with equivalent performance. They are suitable for all forms of construction and all sand/cement designations as specified in BS 4721 are available, as are the new mortar classes to BS EN The sand and cement is accurately batched by weight and the admixtures and water are precisely metered, eliminating the inaccuracies of site mixing. Both air entraining and the cement control-set admixtures comply with BS 4887 (BS EN from 2003). Our mortars are discharged on site into 0.25 cubic metre tubs. Coloured mortars A wide range of coloured mortars are available. They can be used to match or contrast with most bricks and are suitable for both modern and traditional buildings. Accurate batching ensures colour consistency, while the pigments, which are stable and permanent and guaranteed by the manufacturers, comply with the requirements of BS EN : 1999 and have no adverse effect on the mortar s performance. Your Premix sales contact will provide samples to assist with colour selection and advise on the final specification. Quality control Hanson is a member of the Mortar Industry Association, and our Premix mortars are produced in accordance with the association s Quality Scheme for Factory Produced Mortar. Our trained staff supervise all aspects of manufacture and we also provide technical advice to customers and specifiers. Regular site visits are carried out to check material quality and random samples are taken and tested under controlled laboratory conditions. Premix mortars 3

4 Retardation and setting times Premix mortars contain a cement control-set admixture and will remain usable, when stored in the covered tub, for up to two working days. When used in masonry, they set like site mixed mortar and with equivalent performance. The normal setting time depends on sufficient suction taking place from the mortar to the brick or block. If the unit is saturated, or worse still frozen, the bond is impaired and hydration of the cement will not take place for the full period of retardation Consideration should be given to local site conditions and the length of time that unpropped walls are vulnerable to collapse. Independent advice is available from the Mortar Industry Association. After the initial set begins, Premix mortars should not be used or remixed with water. Reduced workability through evaporation may be restored by adding small amounts of water on the spot board and thorough hand-mixing. Further admixtures should never be added. Strength and durability Strict quality control guarantees that the minimum cube strengths specified in BS 4721 or BS EN are exceeded, while variability and standard deviation are reduced compared to sitemixed mortars. Details of typical characteristic strengths of Premix mortars are available on request. When specified correctly and used in accordance with the relevant codes of practice, our mortars last as long as the structure. The admixtures are non-aggressive and cause no corrosion of embedded metal such as brickwork ties. However, all mortars containing Portland cements may contribute to corrosion of zinc or aluminium components in exposed, continually wet conditions. Air content Air entrainment produces the desired plasticity, while eliminating the problems of bleeding often associated with high water content. Where relevant, the range in which the air content falls will be declared, as specified by BS EN Frost resistance The frost resistance of masonry depends on the specification of suitable materials. It is also important that the composition of the mortar is to a consistently high standard, good workmanship and site practice are adopted and the correct joint profile is achieved (see page 5). The entrained air in Premix mortars increases resistance to frost attack in the hardened state and improves long term freeze/thaw durability. Rain penetration Resistance to rain penetration is important to the durability of masonry and we recommend that the relevant codes of practice are always followed. Fire protection Premix mortars are noncombustible as defined in BS 476 Parts 4 and 8. 4 Premix mortars

5 Exposure and mortar designation Choice of joint profile When designing and detailing a building, it is essential that the masonry materials are suitable for the expected exposure conditions. The type of joint profile must be suitable for the degree of exposure. There are four pointing profiles in general use. Weather-struck Bucket-handle The general degree of exposure of the site according to geographical location can be determined from BS 5628 Part 3. Consideration should be given to local conditions, such as the predominant wind direction, the exposure of individual components in the building and the likelihood of frost or sulphate attack. Premix mortars are available in all four traditional sand/cement mortar designations in general use and the new BS EN mortar classes. Although the choice of mortar designation can be complex, the general suitability for mortars to be used in jointing exposed to different weather conditions is indicated right. When masonry is to be constructed in exposed conditions, it is essential that the strength and other physical properties of both mortar and the units or background are compatible see BS 5628 and BS 5262 respectively. Weather-struck: Satisfactory for all degrees of exposure. The joint is ironed, closing the surface of the mortar, and inclined to the lower edge to shed water. The ironing produces a good bond between mortar and units. Good workmanship is required to obtain a uniform colour and texture. Bucket-handle: Satisfactory for all degrees of exposure. The mortar surface is lightly ironed to obtain a close texture, again resulting in a good bond between mortar and units. Care is needed to obtain uniform colour and texture of joints. Over tooling can affect the surface colour of the mortar. Flush: Suitable for moderate and sheltered exposure conditions. The joint is not ironed, resulting in an open texture. Good workmanship is necessary for a good bond between mortar and units, but produces a uniform colour texture. Raked: Suitable for sheltered and some moderately exposed conditions only. A special tool such as a chariot should be used to rake the joint to a consistent depth, never more than halfdistance between the unit face Flush and any perforations. Gives excellent uniformity of colour and shade. Note that the various types of joint profile will produce a different appearance in finished brickwork, particularly when coloured mortars are used. Bricklaying practice All masonry construction demands good workmanship. It is recommended that units are bedded and pointed in one operation to maximise the durability of the joints. Horizontal bed joints should never be furrowed (where the centre of the bed is removed or left unfilled). Tipping or buttering vertical edges of the bricks results in failure to fill the perpend-joint. All perpend faces of bricks should be fully buttered before placing. Newlylaid brickwork, particularly the tops Raked Premix mortars 5

6 of partially completed walls, should be suitably protected from adverse weather. Unprotected tops of walls that become saturated may cause unsightly efflorescence in the masonry. Bricks and blocks should be stacked on pallets and never directly on the ground. Stockpiles should be protected from the weather and never allowed to become saturated or frozen. Winter working Premix mortars are air entrained and therefore more resistant to frost attack in the hardened state but they should be used in accordance with Section 5 of BS , which prohibits bricklaying at temperatures below 3 C and falling. When temperatures are expected to fall below freezing, regardless of temperature at the time of laying, it is essential that newlybuilt masonry is suitably protected. Low temperatures reduce the setting rate of any mortar and increase the length of time that unpropped walls are vulnerable to collapse. Any frozen crust on mortars left in unprotected tubs should be discarded. The unfrozen mortar may be used provided the mortar temperature is no lower than 4 C, the ambient air temperature is suitable and the bricks or blocks are not saturated or frosted. Independent advice is available from the Mortar Industry Association. Health and safety All building mortars are abrasive and alkaline, with a typical ph value of 12 when wet. Contact with wet cement and lime mixes such as mortar can cause burns and skin diseases including: Cement burns that develop slowly and, if exposure is prolonged, may continue to develop even after washing. Irritant contact dermatitis, caused by the combination of wetness, alkalinity and abrasiveness of the mixture. Allergic contact dermatitis, caused by individual sensitivity to the chromium compounds which may occur in cement. If your eyes, or patches of skin, come into contact with concrete, mortar, cement slurry or residue, wash immediately and thoroughly with clean water. Clothes impregnated with wet mortar should be taken off and the skin washed thoroughly. At the time of contact and immediately after, only irritation may be felt. The alkali may take several hours to be absorbed into the deep tissues and will then give rise to rawness and blisters. If irritation persists after washing, seek medical attention. Do not kneel or sit on wet mortar as harmful contact can occur through saturated clothing. Protective clothing should be worn, particularly on the arms, hands, legs and feet, for example long-sleeved clothing, full-length trousers and impervious gloves and boots. A full 0.25 cubic metre plastic tub of mortar weighs approximately 450kg. When tubs are to be placed on scaffold boards, advice should be sought from the scaffolding contractor as to the strength and suitability of the scaffolding. A COSHH health and safety data sheet is available on request and one can be sent with the initial delivery to each new site. Hazard label data: This product is not classified as dangerous for supply in the UK. 6 Premix mortars

7 Environmental Prevent entry into drains and watercourses. Test panels Before placing an order, especially for coloured mortar, it is recommended that a site test panel is constructed to ensure compatibility and colour match with the specified bricks and blocks. Adequate time should be allowed for the panel to dry out and it should be protected from the weather. Your local sales contact will arrange for samples to be delivered. These can be ready-touse, or dry for addition of cement and water on site. Ordering Premix mortars can be ordered from your local sales office listed overleaf and on your contract quotation. Please give the job reference or quote number. We recommend at least two full working days notice for delivery of the empty tubs and call-off of your initial delivery. Subsequent orders should be placed before 3pm for delivery the following day. We recommend you order enough mortar for use the next morning, or to last until your next delivery arrives. Quantity One cubic metre of Premix mortar is sufficient to lay approximately 1,500 Fletton-type frogged bricks, or about 1,000 blocks with a nominal size of 450mm x 225mm x 100mm. In practice these figures may vary widely depending on unit size, depth of frog, number and size of perforations, joint thickness and the amount of wastage. Your local sales contact will offer advice. Delivery Mortar is discharged into our own purpose-built 0.25 cubic metre calibrated tubs (four tubs per cubic metre). The tubs should be positioned at a central, level point with adequate access for a truck mixer or similar size vehicle. This will allow easy distribution throughout the site. To avoid contamination and the resultant loss of retardation, it is essential that tubs are emptied and thoroughly cleaned before fresh mortar is delivered. Fresh deliveries of mortar will be covered to provide protection from the weather and to avoid loss of moisture from the mortar. In extreme weather conditions it is advisable that the customer provides additional protection. Premix the choice in mortars Premix mortars 7

8 Premix the choice in mortars Premix mortar sales and enquiries Scotland Northern England North Wales/north west England Central England/ east and west midlands/ East Anglia London South east/home counties /5634 Cornwall/Devon/Dorset Oxon/Wilts/Glos/Bristol/Somerset/ west Berks/west Hants Need help or advice with any of our products? Visit our website at us at