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64-700: The Burnley Embankment is an embankment carrying the Leeds and Liverpool Canal across the Calder and Brun valleys in Burnley , Lancashire . Also known as the Straight Mile , the embankment is 1,256 yards (0.714 mi; 1.148 km) long and the canal runs up to 60 feet (18 m) above the valley floor. The structure was chosen as one of the original Seven Wonders of the Waterways , and has been awarded

128-629: A Red Wheel by the Transport Trust . The building of the Leeds and Liverpool Canal began in 1770, but work on the over-budget project was suspended during the American War of Independence , leaving separate sections extending from the two cities. Under the original plan, the canal's route would have passed Burnley on the northern side of the River Calder , crossing at Whalley via an aqueduct . Burnley would have been connected by

192-569: A bridge . Lime mortar With the introduction of Portland cement during the 19th century, the use of lime mortar in new constructions gradually declined. This was largely due to the ease of use of Portland cement, its quick setting, and high compressive strength. However, the soft and porous properties of lime mortar provide certain advantages when working with softer building materials such as natural stone and terracotta . For this reason, while Portland cement continues to be commonly used in new brick and concrete construction, its use

256-496: A Roman architect, provided basic guidelines for lime mortar mixes. The Romans created hydraulic mortars that contained lime and a pozzolan such as brick dust or volcanic ash. These mortars were intended to be used in applications where the presence of water would otherwise not allow the mortar to harden (carbonate) properly. Lime mortar today is primarily used in the conservation of buildings originally built using it, but may be used as an alternative to ordinary portland cement. It

320-548: A branch heading up the valley. Before work on the canal resumed heading west from Gargrave , in 1790, permission was obtained to move the route to the south, with the river crossing between Filly Close in Reedley Hallows and Ightenhill . By the fourth act, Leeds and Liverpool Canal Act 1794 ( 34 Geo. 3 . c. 94), this part of the route was settled, moving south again. At Burnley, the River Calder and its tributary

384-459: A change in level required by the terrain , the alternatives being either to have an unacceptable change in level or detour to follow a contour. A cutting is used for the same purpose where the land is originally higher than required. Embankments are often constructed using material obtained from a cutting. Embankments need to be constructed using non-aerated and waterproofed, compacted (or entirely non-porous) material to provide adequate support to

448-606: A kiln. Burning shells in a rick is something that Colonial Williamsburg and the recreation of Ferry Farm have had to develop from conjecture and in-the-field learning. The rick that they constructed consists of logs set up in a circle that burn slowly, converting oysters that are contained in the wood pile to an ashy powder. An explanatory video of how the rick was built for the Ferry Farm can be found here . The burnt shell can then be slaked and turned into lime putty. Mortars using oyster shells can sometimes be identified by

512-420: A lime putty is an exothermic reaction which initially creates a liquid of a creamy consistency. This is then matured for 2 to 3 months—depending upon environmental conditions—to allow time for it to condense and mature into a lime putty. A matured lime putty is thixotropic , meaning that when a lime putty is agitated it changes from a putty into a more liquid state. This aids its use for mortars as it makes

576-431: A lump for some time, without it drying out (it may get a thin crust). When ready to use, this lump may be remixed ('knocked up') again and then used. Traditionally on building sites, prior to the use of mechanical mixers, the lime putty (slaked on site in a pit) was mixed with sand by a labourer who would "beat and ram" the mix with a "larry" (a wide hoe with large holes). This was then covered with sand and allowed to sit for

640-409: A material which is not as "fatty”, being a common trade term for compounds have a smoother buttery texture when worked. Often, due to lengthy and poor storage, the resulting lime produced by hydrated lime will exhibit longer carbonatation periods as well as lower compressive strengths. Non-hydraulic lime takes longer to set and is weaker than hydraulic lime, and should not be allowed to freeze before it

704-515: A more stable mortar. The stability and predictability make the mixed mortar more user friendly, particularly in applications where entire wall sections are being laid. Contractors and designers may prefer mixes that contain Portland due to the increased compressive strength over a straight lime mortar. As many pre-Portland mix buildings are still standing and have original mortar, the arguments for greater compressive strength and ease of use may be more

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768-452: A mortar easier to work with. If left to stand following agitation a lime putty will slowly revert from a thick liquid to a putty state. As well as calcium-based limestone, dolomitic limes can be produced which are based on calcium magnesium carbonate . A frequent source of confusion regarding lime mortar stems from the similarity of the terms hydraulic and hydrated. If the quicklime is slaked with an excess of water then putty or slurry

832-400: A port on the canal, the town expanded during the 19th century—the population doubled in the first 20 years—and land near the canal was used for terraced housing (including some back-to-backs ) and numerous cotton mills, warehouses and wharves. Although the arrival of the canal was a very significant event in the growth and development of Burnley, stimulating the local textile and coal trade,

896-431: A process known as spalling , the process by which the outer face of a brick degrades and can flake off or turn to powder. There is also a natural movement of water through a masonry wall. A strong Portland cement mix will prevent a free flow of water from a moist to dry area. This can cause rising damp to be trapped within the wall and create system failures. If moisture can not escape into the air, it will cause damage to

960-423: A similar or weaker mortar. Therefore, a straight lime mortar joint should be repointed in kind. Due to the popularity of Portland cement, this often is not the case. A wall system needs a balance between the mortar and brick that allows the mortar to be the weak part of the unit. When mortar is stronger than the brick, it prevents any natural movement in the wall and the faces of the brick will begin to deteriorate,

1024-484: A similar type or reconstruction of buildings using historically correct methods. In the past, lime mortar tended to be mixed on site with whatever sand was locally available. Since the sand influences the colour of the lime mortar, colours of pointing mortar can vary dramatically from district to district. Hydraulic lime contains substances which set by hydration , so it can set underwater. Non-hydraulic lime sets by carbonation and so needs exposure to carbon dioxide in

1088-454: A stronger lime mortar is required, such as for external or structural purposes, a pozzolan can be added, which improves its compressive strength and helps to protect it from weathering damage. Pozzolans include powdered brick, heat treated clay, silica fume , fly ash , and volcanic materials. The chemical set imparted ranges from very weak to almost as strong as Portland cement. This can also assist in creating more regulated setting times of

1152-421: A time of year where the weather conditions are conducive to the mortar setting properly. Those conditions are not only above freezing temperatures but also drier seasons. To protect the slow curing mortar from damp, a siloxane can be added to the surface. With historic structures, this may be a controversial strategy as it could have a detrimental effect to the historic fabric. The presence of Portland allows for

1216-430: A wall structure. Water freezing in the wall is another cause of spalling. In restoration work of pre-20th century structures, there should be a high ratio of lime and aggregate to Portland. This reduces the compressive strength of the mortar but allows the wall system to function better. The lime mortar acts as a wick that helps to pull water from the brick. This can help to prevent the older brick from spalling. Even when

1280-498: A while (from days to weeks) - a process known as "banking". This lump was then remixed and used as necessary. This process cannot be done with Portland cement. The combination of Portland cement and lime is used for stabilization and solidification of the ground through establishing of lime cement columns or stabilization of the entire upper mass volume. The method provides an increase in strength when it comes to vibrations, stability and settling. When building e.g. roads and railways,

1344-597: Is aligned approximately north–south with the towpath on the western side. At the northern end was the Bank Hall estate , owned by John Hargreaves. The estate is now the site of Thompson Park , where the Sandy Holme Aqueduct carries the canal over the River Brun . Here, Godley Lane had to be diverted to meet the bridge that was constructed. While at the southern end, Finsley was presumably a farm before

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1408-403: Is done in a lime kiln . The quicklime is then slaked : hydrated by being thoroughly mixed with enough water to form a slurry (lime putty), or with less water to produce dry powder. This hydrated lime (calcium hydroxide) naturally turns back into calcium carbonate by reacting with carbon dioxide in the air, the entire process being called the lime cycle . The slaking process involved in creating

1472-447: Is known as "The Culvert", although it is an aqueduct not a culvert . This was originally constructed in 1797 as a single horseshoe archway , 70 feet (21 m) from end to end, with a maximum height above the roadway of 14 feet (4.3 m) and maximum width of 22 feet 6 inches (6.86 m). A sandstone retaining wall on the east side of the embankment, immediately north of Yorkshire Street, features four lime kilns built at

1536-407: Is made principally of lime (hydraulic, or non hydraulic as explained below), water, and an aggregate such as sand. Portland cement has proven to be incompatible with lime mortar because it is harder, less flexible, and impermeable. These qualities lead to premature deterioration of soft, historic bricks so traditionally, low-temperature-fired lime mortars are recommended for use with existing mortar of

1600-444: Is not recommended in the repair and restoration of brick and stone-built structures originally built using lime mortar. Despite its enduring utility over many centuries ( Roman concrete ), lime mortar's effectiveness as a building material has not been well understood; time-honoured practices were based on tradition, folklore and trade knowledge, vindicated by the vast number of old buildings that remain standing. Empirical testing in

1664-406: Is produced from a high purity source of calcium carbonate such as chalk, limestone, or oyster shells. Non-hydraulic lime is primarily composed of (generally greater than 95%) calcium hydroxide , Ca(OH) 2 . Non-hydraulic lime is produced by first heating sufficiently pure calcium carbonate to between 954° and 1066 °C, driving off carbon dioxide to produce quicklime ( calcium oxide ). This

1728-469: Is produced. If just the right quantity of water is used, the result is a dry material (any excess water escaping as steam during heating). This is ground to make hydrated lime powder. Hydrated, non-hydraulic lime powder can be mixed with water to form lime putty. Before use putty is usually left in the absence of carbon dioxide (usually under water) to mature. Putty can be matured for as little as 24 hours or for many years; an increased maturation time improves

1792-469: Is referred to as “gauging”. Other than Portland, ash and brick dust have been used to gauge mortars. For historic restoration purposes, and restoration work involving repointing or brick replacement, masons must discover the original brick and mortar and repair it with a similar material. The National Park Service provides guidance for proper masonry repointing through Preservation Brief 2 . In general, Brief 2 suggests that repointing should be done with

1856-476: Is related to Latin limus ('slime, mud, mire'), and linere ('to smear'). Mortar is a mixture with cement and comes from Old French mortier ('builder's mortar, plaster; bowl for mixing') in the late 13th century and Latin mortarium ('mortar'). Lime is a cement which is a binder or glue that holds things together but cement is usually reserved for Portland cement. Lime mortar appeared in Antiquity .

1920-423: Is slaked enough to convert the calcium oxide to calcium hydroxide but not with sufficient water to react with the dicalcium silicate. It is this dicalcium silicate which in combination with water provides the setting properties of hydraulic lime. Aluminium and magnesium also produce a hydraulic set, and some pozzolans contain these elements. There are three strength grades for natural hydraulic lime, laid down in

1984-406: Is well set. Although the setting process can be slow, the drying time of a lime mortar must be regulated at a slow rate to ensure a good final set. A rapidly dried lime mortar will result in a low-strength, poor-quality final mortar often displaying shrinkage cracks. In practice, lime mortars are often protected from direct sunlight and wind with damp hessian sheeting or sprayed with water to control

Burnley Embankment - Misplaced Pages Continue

2048-441: The 1840s to allow water to be taken from the canal to power the mill engines . The embankment, carrying the canal 60 feet (18 m) above the mills, provided a suitable head of water for the mill owners and sluices were built to control abstraction . Both Hill Top and Rishton mills, once among the town's largest cotton mills , were demolished to make way for an Odeon Cinema which was built in 1937. Other businesses which used

2112-562: The Brun meet in a broad valley, building the crossing still further up the Calder was considered, but the Towneley family objected to the canal coming so close to Towneley Hall . The embankment was built between 1796 and 1801 as an alternative to lock flights on each side of the valley. The embankment was designed by Robert Whitworth , who oversaw its construction until his death in 1799; he

2176-602: The European Norm EN459; NHL2, NHL3.5 and NHL5. The numbers stand for the minimum compressive strength at 28 days in newtons per square millimeter (N/mm ). For example, the NHL 3.5 strength ranges from 3.5 N/mm (510 psi) to 10 N/mm (1,450 psi). These are similar to the old classification of feebly hydraulic, moderately hydraulic and eminently hydraulic, and although different, some people continue to refer to them interchangeably. The terminology for hydraulic lime mortars

2240-476: The European continent that the reclassification has greatly improved the understanding and use of lime mortars. Traditional lime mortar is a combination of lime putty and aggregate (usually sand). A typical modern lime mortar mix would be 1 part lime putty to 3 parts washed, well graded, sharp sand . Other materials have been used as aggregate instead of sand. The theory is that the voids of empty space between

2304-427: The air; the material cannot set underwater or inside a thick wall. For natural hydraulic lime (NHL) mortars, the lime is obtained from limestone naturally containing a sufficient percentage of silica and/or alumina. Artificial hydraulic lime is produced by introducing specific types and quantities of additives to the source of lime during the burning process, or adding a pozzolan to non-hydraulic lime. Non-hydraulic lime

2368-666: The ancient Egyptians were the first to use lime mortars about 6,000 years ago ,they used lime to plaster the Giza pyramids. In addition, the Egyptians also incorporated various limes into their religious temples as well as their homes. Indian traditional structures were built with lime mortar, some of which are more than 4,000 years old (such as Mohenjo-daro , a heritage monument of Indus Valley civilization in Pakistan ). The Roman Empire used lime-based mortars extensively. Vitruvius ,

2432-469: The arch with many of the stone blocks decorated with shortbread vermiculation , and tapered wings support the surrounding earth. Considerable time had to be allowed for the embankment to settle before it was stable enough to carry water, but once it was ready the canal opened to Clayton-le-Moors in 1801. The town lies at the centre of the Burnley Coalfield , and the canal was routed through

2496-418: The arrival of the canal saw it converted into a wharf and important maintenance yard. The c. 1700 house became the home of the engineer who operated the swing bridge originally thought to be a sufficient crossing for Finsley Gate. About halfway along the embankment, the canal crosses Yorkshire Street (previously known as East Gate)—the only method of crossing the waterway at any point along its length. This

2560-465: The brick is a modern, harder element, repointing with a higher ratio lime mortar may help to reduce rising damp. It may not be advisable for all consumers to use a straight lime mortar. With no Portland in the mix, there is less control over the setting of the mortar. In some cases, a freeze thaw cycle will be enough to create failure in the mortar joint. Straight lime mortar can also take a long time to fully cure and therefore work needs to be performed at

2624-456: The canal side here probably supported a return wheel for the system. Another change that may have influenced the altered route of the canal was the rapid growth in the cotton industry here after 1780. The area between the south end of Church Street and the embankment became dominated by factories during the early 19th century. The earliest factory development was Scar Top Mill, built as a woollen mill in 1787 and later used for cotton spinning. This

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2688-419: The drying rates. But it also has the quality of autogenous healing (self healing) where some free lime dissolves in water and is redeposited in any tiny cracks which form. In the tidewater region of Maryland and Virginia, oyster shells were used to produce quicklime during the colonial period. Similar to other materials used to produce lime, the oyster shells are burned. This can be done in a lime rick instead of

2752-460: The embankment became a physical barrier to the eastward expansion of the town. By 1851, buildings occupied much of the space on the western side, but only a small area around the recently opened St Mary's Church to the east. At this time Burnley Wood was still developing as a discrete settlement. In 1878 Godley Lane was closed to be replaced by Ormerod Road, and the Finsley Gate swing bridge

2816-519: The embankment included three corn mills that had been established on the western side by 1851. The oldest, built in 1809 a little way south of Yorkshire Street, had already been converted for other uses. Both Hill Top, built around 1838, and Pilling Field (1825) mills had been constructed up the embankment, with direct access to the towpath. Pilling Field—also known as Aqueduct Mill—was the last corn mill to close in Burnley; production ended in 1912 and it

2880-424: The formation and a long-term level surface with stability. An example material for road embankment building is sand-bentonite mixture often used as a protective to protect underground utility cables and pipelines. To intersect an embankment without a high flyover, a series of tunnels can consist of a section of high tensile strength viaduct (typically built of brick and/or metal) or pair of facing abutments for

2944-485: The increased traffic, the expansion of the Burnley Corporation Tramways , and the introduction of double-decker bus services. On the aqueduct is a crane, used for the movement of stop planks to temporarily dam the canal for maintenance. In 1997, the aqueduct over the River Calder, situated within the embankment, was given Grade II listed status. The four lime kilns near The Culvert gained

3008-438: The late 20th century provided a scientific understanding of its remarkable durability. Both professionals and do-it-yourself home owners can purchase lime putty mortar (and have their historical mortar matched for both color and content) by companies that specialize in historical preservation and sell pre-mixed mortar in small batches. Lime comes from Old English lim ('sticky substance, birdlime, mortar, cement, gluten'), and

3072-579: The method is more common and widespread (Queen Eufemias street in Central Oslo, E18 at Tønsberg etc.). For preservation purposes, Type N and Type O mortars are often used. A Type N mortar is 1 part Portland, 1 part Lime and 6 parts sand or other aggregate (1:1:6). A Type O mortar is 1 part Portland, 2 parts Lime and 9 parts sand or other aggregate (1:2:9). Straight lime mortar has no Portland, and 1 part Lime to 3 parts sand or other aggregate. The addition of cement or other pozzolan to decrease cure times

3136-511: The mortar as the pozzolan will create a hydraulic set, which can be of benefit in restoration projects when time scales and ultimately costs need to be monitored and maintained. Hydraulic lime can be considered, in terms both of properties and manufacture, as part-way between non-hydraulic lime and Portland cement. The limestone used contains sufficient quantities of clay and/or silica . The resultant product will contain dicalcium silicate but unlike Portland cement not tricalcium silicate . It

3200-532: The mortar is often applied in thicker coats to compensate for the irregular surface levels. If shrinkage and cracking of the lime mortar does occur this can be as a result of either A common method for mixing lime mortar with powdered lime is as follows: Hair reinforcement is common in lime plaster and many types of hair and other organic fibres can be found in historic plasters. However, organic material in lime will degrade in damp environments particularly on damp external renders. This problem has given rise to

3264-449: The presence of small bits of shell in the exposed mortar joint. In restoration masonry, the bits of shell are sometimes exaggerated to give the viewer the impression of authenticity. Unfortunately, these modern attempts often contain higher than necessary ratios of Portland cement . This can cause failures in the brick if the mortar joint is stronger than the brick elements. Hydraulic lime sets by reaction with water called hydration. When

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3328-430: The quality of the putty. There is an argument that a lime putty which has been matured for an extended period (over 12 months) becomes so stiff that it is difficult to work. There is some dispute ( Roman concrete ) as to the comparative quality of putty formed from dry hydrated lime compared with that produced as putty at the time of slaking. It is generally agreed that the latter is preferable. A hydrated lime will produce

3392-542: The same status at the same time. In June 2012, a Transport Trust Red Wheel commemorated the engineering of the waterway, stating that it was the "largest canal embankment in Britain". Embankment (earthworks) An embankment is a raised wall, bank or mound made of earth or stones, that are used to hold back water or carry a roadway. A road , railway line , or canal is normally raised onto an embankment made of compacted soil (typically clay or rock-based) to avoid

3456-602: The sand particles account for 1/3 of the volume of the sand. The lime putty, when mixed at a 1:3 ratio, fills these voids to create a compact mortar. Analysis of mortar samples from historic buildings typically indicates a higher ratio of around 1 part lime putty to 1.5 part aggregate/sand was commonly used. This equates to approximately 1 part dry quicklime to 3 parts sand. A traditional coarse plaster mix also had horse hair added for reinforcing and control of shrinkage, important when plastering to wooden laths and for base (or dubbing) coats onto uneven surfaces such as stone walls where

3520-460: The time of the embankment. A further two kilns, on the west side of the embankment, were built to provide lime mortar for masonry and clay for puddling the canal. The aqueduct over the River Calder is closer to the southern end, having been built between 1795 and 1796. Visually similar to the original road crossing, the portals are described as a "single semi-circular-headed arch with radiating voussoirs ". There are pilasters to either side of

3584-499: The town to provide transportation for the coal industry. During the first half of the 19th century, Fulledge Colliery to the east side of the embankment was linked to the canal by a tramroad. On the other side, the Burnley Drift passed under the southern end. A mine owned by Rev. Hargreaves caused a major collapse of the embankment as it extracted coal from directly underneath. The Calder culvert had to be partly rebuilt. There

3648-458: The use of polypropylene fibres in new lime renders Usually any dampness in the wall will cause the lime mortar to change colour, indicating the presence of moisture. The effect will create an often mottled appearance of a limewashed wall. As the moisture levels within a wall alter, so will the shade of a limewash. The darker the shade of limewash, the more pronounced this effect will become. A load of mixed lime mortar may be allowed to sit as

3712-411: Was also a short dock branch for coal loading at the very end, next to Finsley Gate. In the latter half of the century, the older coalmines closed and their sites were built over, but the embankment continued to be used by the colliers. The coal dock at the south end was filled in, superseded by a coal yard connected to Towneley Colliery , located next to Finsley Wharf. Although the tramroad from Fulledge

3776-429: Was demolished in 1939 after John Greenwood and Sons was taken over by Rank Hovis McDougall . Also at the north end, a 200-yard (180 m) rope walk was established on the embankment, parallel to the canal. The canal embankment shaped the built environment in Burnley. At the time of its construction, the embankment was on the periphery of the town centre and followed a route through open fields. With Burnley becoming

3840-415: Was improved by the skilled French civil engineer Louis Vicat in the 1830s from the older system of water limes and feebly, moderately and eminently. Vicat published his work following research of the use of lime mortars whilst building bridges and roads in his work. The French company Vicat still currently produce natural cements and lime mortars. Names of lime mortars were so varied and conflicting across

3904-408: Was joined by Hill Top Mill in 1820 and Rishton Mill after 1830. Later they were extended, with Hill Top and Rishton mills expanding up the embankment to access to the towpath. By the turn of the 20th century, twelve mills were operating alongside the embankment—all but two of which supported the town's textiles industry. Their location was likely influenced by the decision the canal proprietors took in

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3968-431: Was removed, another was added on the opposite bank to supply the town's gasworks on the south side of the Calder. Another coal yard was established on the east side of the embankment, next to Central Mill, connected by a more complex system of tramroads that allowed coal to be delivered from Rowley and Bee Hole pits—opened in 1862 and 1872 respectively—and raise it up to a wharf. A triangular stone structure that survives on

4032-402: Was replaced with a fixed one in 1885. Two side tunnels (known as the "gimlet holes") were added to The Culvert in 1896 to allow pedestrians to cross the embankment without using the main portal . The entire Culvert was rebuilt in 1926 and 1927, increasing the height and widening the aperture to 70 feet (21 m)—the 1797 structure (and additional pedestrian tunnels) were no longer suitable for

4096-461: Was succeeded by former inspector of works Samuel Fletcher . The construction of the embankment cost £22,000 (about £1.6 million in 2019). The embankment used 350,000 cubic yards (270,000 m) of earth , much of which came from the digging of the nearby 559-yard (511 m) Gannow Tunnel and the Whittlefield cutting. The earthwork is 1,256 yards (0.714 mi; 1.148 km) long, it

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