Misplaced Pages

#519480

49-507: Although both grout and its close relative mortar are applied as a thick suspension and harden over time, grout is distinguished by its low viscosity and lack of lime (added to mortar for pliability); grout is thin so it flows readily into gaps, while mortar is thick enough to support not only its own weight, but also that of masonry placed above it. Grout varieties include tiling , flooring , resin , nonshrinking , structural, and thixotropic grouts. The use of enhancing admixtures increases

98-485: A synonym , though its formal definition is technically different. Traditionally, mortar was made with lime and sand, producing lime putty. In the early 20th century, masons began using Portland cement , a strong, fast drying cement. Masonry cement made its appearance in the 1930s, which is a combination of Portland cement and ground limestone . ‹The template How-to is being considered for merging .›   Before starting any actual work, building owners examine

147-462: A certain degree of flexibility to adapt to shifting ground or other changing conditions. Cement mortar is harder and allows little flexibility. The contrast can cause brickwork to crack where the two mortars are present in a single wall. Lime mortar is considered breathable in that it will allow moisture to freely move through and evaporate from the surface. In old buildings with walls that shift over time, cracks can be found which allow rain water into

196-428: A consistent bearing surface between the plate and its substrate, which adds stability and allows for higher load transfers. Portland cement is the most common cementing agent in grout, but thermoset polymer matrix grouts based on thermosets such as urethanes and epoxies are also popular. Portland cement-based grouts include different varieties depending on the particle size of the ground clinker used to make

245-451: A historic structure needs repointing, building owners usually hire an architectural historian or conservator to help pinpoint the issues. If the crack is smaller than 2mm and not causing any major defects, then it is better to leave it and not repoint. It is common to see cracking along old repairs because of the shrinkage of hard mortar and the seasonal flexing along the joint. Examining the structure before working will also help establish

294-439: A lime must be stored as a dry powder. Alternatively, a pozzolanic material such as calcined clay or brick dust may be added to the mortar mix. Addition of a pozzolanic material will make the mortar set reasonably quickly by reaction with the water. It would be problematic to use Portland cement mortars to repair older buildings originally constructed using lime mortar. Lime mortar is softer than cement mortar, allowing brickwork

343-538: A lower firing temperature. It is therefore easier to make than lime mortar and sets up much faster, which may be a reason it was used as the typical mortar in ancient, brick arch and vault construction. Gypsum mortar is not as durable as other mortars in damp conditions. In the Indian subcontinent , multiple cement types have been observed in the sites of the Indus Valley civilization , with gypsum appearing at sites such as

392-406: A rigid aggregate structure; however, the mortar functions as a weaker component than the building blocks and serves as the sacrificial element in the masonry, because mortar is easier and less expensive to repair than the building blocks. Bricklayers typically make mortars using a mixture of sand , a binder , and water. The most common binder since the early 20th century is Portland cement , but

441-462: A sample of mortar is crushed and mixed with a dilute acid. The mortar will be broken down, and the type of mortar and sand used will be determined by color and texture. Another form of "wet chemical" analysis is the same process but the carbon dioxide gas that is given off by the digestion will be collected and the type of mortar will be determined by its volume. The amounts of each component will also be determined. The second method to analyzing mortar

490-424: A soft lime -based mortar was originally used, the most appropriate repointing mortar is likely to also contain a large amount of lime. An architectural conservator can perform a mortar analysis in order to make recommendations for replacement mortar that is both physically and aesthetically compatible with the building. There are two common methods of analyzing mortar. The first is called "wet chemical" in which

539-760: A strong mortar that will also set under water. As the mortar hardens, the current atmosphere is encased in the mortar and thus provides a sample for analysis. Various factors affect the sample and raise the margin of error for the analysis. Radiocarbon dating of mortar began as early as the 1960s, soon after the method was established (Delibrias and Labeyrie 1964; Stuiver and Smith 1965; Folk and Valastro 1976). The very first data were provided by van Strydonck et al. (1983), Heinemeier et al.(1997) and Ringbom and Remmer (1995). Methodological aspects were further developed by different groups (an international team headed by Åbo Akademi University , and teams from CIRCE, CIRCe, ETHZ, Poznań, RICH and Milano-Bicocca laboratory. To evaluate

SECTION 10

#1732855135520

588-535: A structure with Portland cement. As a general rule, however, Portland cement should not be used for the repair or repointing of older buildings built in lime mortar, which require the flexibility, softness and breathability of lime if they are to function correctly. In the United States and other countries, five standard types of mortar (available as dry pre-mixed products) are generally used for both new construction and repair. Strengths of mortar change based on

637-428: A traditional brick, block or stone wall. It is mainly designed for repairing concrete structures. The use of recovered plastics in mortars is being researched and is gaining ground. Depolymerizing PET to use as a polymeric binder to enhance mortars is actively being studied. The setting speed can be increased by using impure limestone in the kiln , to form a hydraulic lime that will set on contact with water. Such

686-444: Is "instrumental." There are several different forms of "instrumental" analysis; however, the most commonly used is thin section microscopy in which thin slices of mortar are examined by a transmitted light microscope. This process can provide more information than "wet-chemical" examination. Other examples of instrumental analysis are scanning electron microscopy , X-ray diffraction , and atomic absorption spectroscopy . Analysis

735-571: Is a workable paste which hardens to bind building blocks such as stones , bricks , and concrete masonry units , to fill and seal the irregular gaps between them, spread the weight of them evenly, and sometimes to add decorative colours or patterns to masonry walls. In its broadest sense, mortar includes pitch , asphalt , and soft clay, as those used between bricks, as well as cement mortar. The word "mortar" comes from Old French mortier , "builder's mortar, plaster; bowl for mixing." (13c.). Cement mortar becomes hard when it cures, resulting in

784-412: Is added. The process is continued until the mortar is flush with the masonry. High-lime mortar dries rapidly, so after it reaches a particular strength it needs to be sprayed with water to avoid chalking, poor adhesion, or poor durability. The structure is misted every two hours for two days, then every four hours for two days. It is important that the mortar stays wet for at least a couple of days while it

833-399: Is an area on the structure out of plain sight where the owner or conservator can test the repointing methods they will use, the color of the mortar, and the skills of the mason. This will also be good to determine the types of tools that should be used, which will be discussed in the next paragraph. For a brick structure, the panel should not be any bigger than 3' x 3'. For other masonry units,

882-412: Is not solely based on lab work, however. There are important performances of mortar that can not be determined in a lab: original water content, rate of curing, weather conditions during original construction, method of mixing and placing the mortar, and cleanliness of sand. It is important to also match the color of the mortar. However, in the past lime mortar tended to be mixed on site with whatever sand

931-426: Is setting. The local conditions will control how long the structure should be kept wet, however. Burlap or plastic is placed over the repointed wall or structure. This keeps the building damp and eliminates direct sunlight. The burlap and the plastic are not resting against the structure, however. The burlap or plastic are anchored to the ground to avoid this. There are different ways to lay the mortar joint close to

980-570: The Mohenjo-daro city-settlement, which dates to earlier than 2600 BCE. Gypsum cement that was " light grey and contained sand, clay, traces of calcium carbonate, and a high percentage of lime " was used in the construction of wells, drains, and on the exteriors of " important looking buildings ." Bitumen mortar was also used at a lower-frequency, including in the Great Bath at Mohenjo-daro. In early Egyptian pyramids, which were constructed during

1029-551: The Old Kingdom (~2600–2500 BCE), the limestone blocks were bound by a mortar of mud and clay, or clay and sand. In later Egyptian pyramids, the mortar was made of gypsum , or lime. Gypsum mortar was essentially a mixture of plaster and sand and was quite soft. 2nd millennia BCE Babylonian constructions used lime or pitch for mortar. Historically, building with concrete and mortar next appeared in Greece . The excavation of

SECTION 20

#1732855135520

1078-478: The 10th millennia BCE buildings of Jericho , and the 8th millennia BCE of Ganj Dareh . According to Roman Ghirshman , the first evidence of humans using a form of mortar was at the Mehrgarh of Baluchistan in what is today Pakistan, built of sun-dried bricks in 6500 BCE. Gypsum mortar, also called plaster of Paris, was used in the construction of many ancient structures. It is made from gypsum, which requires

1127-570: The alternate letters of the words " M a S o N w O r K ". Polymer cement mortars (PCM) are the materials which are made by partially replacing the cement hydrate binders of conventional cement mortar with polymers. The polymeric admixtures include latexes or emulsions , redispersible polymer powders, water-soluble polymers, liquid thermoset resins and monomers. Although they increase cost of mortars when used as an additive, they enhance properties. Polymer mortar has low permeability that may be detrimental to moisture accumulation when used to repair

1176-480: The ancient binder lime (producing lime mortar ) is still used in some specialty new construction. Lime, lime mortar, and gypsum in the form of plaster of Paris are used particularly in the repair and repointing of historic buildings and structures, so that the repair materials will be similar in performance and appearance to the original materials. Several types of cement mortars and additives exist. The first mortars were made of mud and clay , as demonstrated in

1225-430: The bottom brick and recesses back as it goes up towards the upper brick. The third, recessed, is when the mortar sits back from the face of the brick. There is also tuckpointing , where a mortar of a contrasting colour is 'tucked' into the masonry joint. If the color of the new mortar is still not similar to the old mortar after repointing and setting, the non-repointed areas of the structure can be cleaned. This may bring

1274-417: The cement, with a standard size around 15 microns , microfine from 6–10 microns, and ultrafine below 5 microns. Finer particle sizes let the grout penetrate more deeply into a fissure. Because these grouts depend on the presence of sand for their basic strength, they are often somewhat gritty when finally cured and hardened. From the different types of grout, a suitable one has to be chosen depending on

1323-430: The colors closer together. To do this, a low pressure water jet is used to clean the old pointing. A high powered water jet is not to be used because this could damage the masonry and mortar. Chemicals are also not used with the water because this could be harmful to the masonry or mortar. However, if chemicals are used, the structure is rinsed afterwards with fresh water and natural or nylon brushes. Another method to match

1372-427: The different anthropogenic carbon extraction methods for radiocarbon dating as well as to compare the different dating methods, i.e. radiocarbon and OSL, the first intercomparison study (MODIS) was set up and published in 2017. Repointing Repointing is the process of renewing the pointing, which is the external part of mortar joints , in masonry construction. Over time, weathering and decay cause voids in

1421-411: The edge of the brick. Some contractors bring the mortar to the very edge, flush with the face of the brick. Others leave it recessed back to allow water to shed off the building. There are three types of recessed mortar: bucket handle, weatherstruck, and simply recessed. The bucket handle is when the mortar is in a curve shape away from the face of the brick. Weatherstruck is when the mortar starts close to

1470-409: The grout. The sanded variety contains finely ground silica sand; unsanded is finer and produces a smoother final surface. They are often enhanced with polymers and/or latex . Structural grout is often used in reinforced masonry to fill voids in masonry housing reinforcing steel, securing the steel in place, and bonding it to the masonry. Nonshrinking grout is used beneath metal bearing plates to ensure

1519-425: The joint, or to the point where sound mortar is reached. Removal of old mortar between joints is done carefully to avoid damage to masonry units. On buildings with soft materials, such as under-fired brick, lime mortar , or terra cotta, removal by hand is often the most effective to avoid damage. Hard Portland cement mortar is usually removed with a grinder or power circular masonry blade, taking care not to damage

Grout - Misplaced Pages Continue

1568-416: The joints between masonry units, usually in bricks , allowing the undesirable entrance of water. Water entering through these voids can cause significant damage through frost weathering and from salt dissolution and deposition . Repointing is also called pointing , or pointing up , although these terms more properly refer to the finishing step in new construction. Tuckpointing is also commonly used as

1617-491: The lime to set relatively quickly and even under water. Vitruvius , the Roman architect, spoke of four types of pozzolana. It is found in all the volcanic areas of Italy in various colours: black, white, grey and red. Pozzolana has since become a generic term for any siliceous and/or aluminous additive to slaked lime to create hydraulic cement. Finely ground and mixed with lime it is a hydraulic cement, like Portland cement, and makes

1666-502: The load. For example, a load up to 7.5 tons can be expected for a garage access [two-component pavement joint mortar (traffic load)], whereas a cobbled garden path is only designed for a pedestrian load [one-component pavement joint mortar (pedestrian load)]. Furthermore, various substructures determine whether the type of grout should be permanently permeable to water or waterproof, for example, by concrete subfloor. Tools associated with groutwork include: Mortar (masonry) Mortar

1715-404: The masonry units, mortar, and the techniques used in the original construction. They try to identify the true problem they are facing and find out what were the causes of the deterioration or cracks. If there are cracks or problems in the actual bricks or stone masonry there could be a larger problem that also needs to be addressed. If there is a larger issue, repointing may cause further damage. If

1764-419: The masonry units. After the mortar has been cut out, the joints are vacuumed or brushed clean. After vacuuming, the remaining debris is removed with a water jet from the top of the masonry area down. The areas with the deepest recession of mortar are filled first. The mortar is placed in several layers, starting with the first layer of 1/4 inch. It is hardened to a desired strength then another 1/4 inch layer

1813-505: The masonry units. Vertical joints or thin joints are done by hand or with small power chisels." If a power saw needs to be used, it's only used on wide and uniform horizontal joints and in the middle of the joint. A hammer and chisel are then used for the rest of the mortar, closer to the masonry units. Caulking cutters with diamond blades are an acceptable power tool to remove mortar in wide horizontal joints. They are slow, have no rotation, and vibrate so they are likely to cause less damage to

1862-492: The mix ratio for each type of mortar, which are specified under the ASTM standards. These premixed mortar products are designated by one of the five letters, M, S, N, O, and K. Type M mortar is the strongest, and Type K the weakest. The mix ratio is always expressed by volume of Portland cement : lime : sand {\displaystyle {\text{Portland cement : lime : sand}}} . These type letters are apparently taken from

1911-444: The original mortar. The mortar should also not be stronger (in compressive strength) than the masonry units because it will not have give. Rather than the mortar relieving the stress, the masonry units will, thus suffering further damage such as cracking or spalling. In spallation , the face or outer section of a masonry unit breaks away from the rest of the unit. This will require expensive and laborious repairs. So for example, if

1960-412: The quality of cement-based materials and leads to greater uniformity of hardened properties. Tiling grout is often used to fill the spaces between tiles or mosaics and to secure tile to its base. Although ungrouted mosaics do exist, most have grout between the tesserae . Tiling grout is also cement-based, and is produced in sanded and unsanded varieties, which affects the strength, size, and appearance of

2009-526: The strength and permeability of the original mortar in order to match the new. It helps to establish what the original components of the old mortar are in order to find the best match. It is essential that the mortar used for repointing have similar performance characteristics to the original mortar used in a building. Such performance characteristics include permeability, compressive strength , and coefficient of thermal expansion . The mortar must have greater vapor permeability and softer compressive strength than

Grout - Misplaced Pages Continue

2058-544: The structure. The lime mortar allows this moisture to escape through evaporation and keeps the wall dry. Re−pointing or rendering an old wall with cement mortar stops the evaporation and can cause problems associated with moisture behind the cement. Pozzolana is a fine, sandy volcanic ash . It was originally discovered and dug at Pozzuoli , nearby Mount Vesuvius in Italy, and was subsequently mined at other sites, too. The Romans learned that pozzolana added to lime mortar allowed

2107-401: The test panel can be a little larger. It is also important to pick the right season to do the repointing. Extremely high or low temperatures can cause rapid drying which can have negative effects on the mortar, masonry units, and the structure itself. After examination, the next step is cutting away the old mortar. The old mortar is removed to a depth equal to or slightly more than the width of

2156-516: The then Greek colony of Dicaearchia ( Pozzuoli ) near Naples, Italy. The Romans later improved the use and methods of making what became known as pozzolanic mortar and cement. Even later, the Romans used a mortar without pozzolana using crushed terra cotta , introducing aluminum oxide and silicon dioxide into the mix. This mortar was not as strong as pozzolanic mortar, but, because it was denser, it better resisted penetration by water. Hydraulic mortar

2205-463: The underground aqueduct of Megara revealed that a reservoir was coated with a pozzolanic mortar 12 mm thick. This aqueduct dates back to c. 500 BCE. Pozzolanic mortar is a lime based mortar, but is made with an additive of volcanic ash that allows it to be hardened underwater; thus it is known as hydraulic cement. The Greeks obtained the volcanic ash from the Greek islands Thira and Nisiros , or from

2254-434: Was invented in 1794 by Joseph Aspdin and patented on 18 December 1824, largely as a result of efforts to develop stronger mortars. It was made popular during the late nineteenth century, and had by 1930 became more popular than lime mortar as construction material. The advantages of Portland cement is that it sets hard and quickly, allowing a faster pace of construction. Furthermore, fewer skilled workers are required in building

2303-414: Was locally available. Since the sand influences the color of the lime mortar, colors of pointing mortar can vary dramatically from district to district. Weathering of the new mortar will also match it to the old mortar. The tooling should also match the tooling of the historic mortar. Again, before starting any work, the methods and materials for the repointing will be applied in a test panel. A test panel

2352-462: Was not available in ancient China, possibly due to a lack of volcanic ash. Around 500 CE, sticky rice soup was mixed with slaked lime to make an inorganic−organic composite sticky rice mortar that had more strength and water resistance than lime mortar. It is not understood how the art of making hydraulic mortar and cement, which was perfected and in such widespread use by both the Greeks and Romans,

2401-573: Was then lost for almost two millennia. During the Middle Ages when the Gothic cathedrals were being built, the only active ingredient in the mortar was lime. Since cured lime mortar can be degraded by contact with water, many structures suffered over the centuries from wind-blown rain. Ordinary Portland cement mortar , commonly known as OPC mortar or just cement mortar, is created by mixing powdered ordinary Portland cement , fine aggregate and water. It

#519480