Characteristics of polymer-Modified Mortar

Mortar is considered as one of the vital components in masonry construction. It is normally formed by mixing water with portland cement, hydrated lime and sand. If the proportions of each of these ingredients are changed, strength and other characteristics may differ. Mortar with polymeric admixtures is applied extensively and inexpensively in definite situations.

Basics and function: Polymer-modified mortar is developed by interchanging a part of the conventional binders with polymers. Polymers are included with mortar to enhance the characteristics which may contribute to adhesion, toughness, flexural or tensile strength, and resistance to chemicals.

The purpose of the polymers is to make the capacity of work and adhesion of non hardened mortar better and often need fewer quantity of extra water as compared to conventional mortar. It leads to less pores and high capacity cements, consequently the immersion of water & and penetrability to salts are decreased.

Types of Polymers: Polymer-modified mortar is commercially obtainable with all constituents already provided in the mixture. Conversely, polymer additives separated into classes, are included with mortar mix. Redispersible polymer powders like ethylene vinyl acetate are normally included with dry mortar mix.

Water-soluble polymers like polyvinyl alcohol belong to powders but are added to wet mortar mix. Aqueous latex suspensions comprise of latex particles hanged up in water to coat hydrating cement particles. At the end, liquid polymers as epoxy resins or unsaturated polyesters are included throughout mixing to develop a network of cemented polymer hydrate and thus the strength of the mixture is raised significantly.

Application: Polymer-modified mortar is employed in a wide array of mortar and concrete repair and primary construction applications. Low water level and salt infiltrations transform polymer-modified mortar suitable for masonry prone to weathering and other exterior conditions. The main objective of polymer-modified thinset mortar is to bind tile to concrete and cement board substrates devoid of immersing the tiles earlier. Polymer-modified mortars are frequently applied for repairing purposes due to their low shrinkage and capacity to tie with even solid surfaces.

Supplementary Possible Admixtures: Besides, polymers, other types of materials can be included with mortars to attain required characteristics. Color pigments may be included with mortar to change the look of the mortar. If accelerators and retarders are included, these can decrease or raise the length of time necessary for the mortar to be cured, a vital characteristic to control in severely cold or warm, humid weather. Other mortar additives range from mineral additions, like silica fume, aggregates and inert fillers, plasticizing chemical admixtures and fibers to manage shrinkage efficiently.



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Published By
Rajib Dey
www.constructioncost.co
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Benefits of joining & pointing in brick masonry

When bricks are not fully uniform in colour and irregular in shape, the joint finishes should be designed to provide correctness and repose to premier facades with formation of the illusion of perfectness.

JOINTING: The finished profile of the original mortar joint is produced instantly since the bricks are placed later in an individual practice called as pointing. Jointing is associated with bricklaying for finishing the joint faces of the bedding mortar as work continues.

Benefits:

• Combined joint
• Consistency of joint in strength and colour, on condition that mortar is properly measured
• Lower labour costs

Drawbacks:

• Less quality control of joint finish (not all bricklayers joint well)
• Complication in retaining consistent colour all through the wall face.

POINTING: Pointing stands for the method of repairing mortar joints among bricks or other masonry elements to resist penetration of rain water or dampness.

Benefits:

• Greater joint finish
• Consistency of colour and strength
• Better choice of joint finishes
• Clean face work

Drawbacks:

• Higher labor and material costs
• Extra construction time
• When improperly performed the compound joint can’t be joined
• Requirement for expert and experienced pointers.

Structural benefits: The bricks consume moisture from the mortar when perfectly dampened prior to laying or pointing. Together with evaporation, it leads to partial de-hydration of the joint towards the joint face. So the purpose of the jointing tool is to solidify the surface of the joints fixing shrinkage cracks and defending from the ingress of driving rain.



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Rajib Dey
www.constructioncost.co
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Various types of masonry Mortar

Mortar is extended in among the masonry, grouts, and stuffs the cavities of the masonry units. Mortar belongs to the material that is visible among the bricks. Mortar allows the masonry units to remain jointly. Mortar is very vital in masonry construction. It is always recommended to apply the proper mortar or grout.

The process is complicated to find out the exact mixture for the mortar or grout for maintaining proper strength. The mortar or grout should contain the perfect strength to get rid of over bearing issue (load bearing in this case). Besides, the mixture that retains the masonry sections together should not be considerably stronger that what the masonry units are, because it can transform the load bearing to gain extreme amount of stress.

If the mortar’s mixture is not provided properly it can lead to weighing over the masonry units themselves and results in damaging the structure with cracking and/or spakling.

The categorization is done on the basis of ASTM C 270 (Standard Specification for Mortar for Unit Masonry). Given below, various categories of mortar.

Mortar-Type M: Mortar (Type M) contains a minimum 2500 psi and suitable for areas to withstand a considerable amount of load bearing, wind forces, earthquakes, and etc. This specific type of mortar is normally applied with stone. If the Mortar is formed with any material that contains less strength, it may collapse the structure and its job positioning prematurely.

Application - This type of mortar is normally applied with stone as it closely simulates the strength of stone, it will not collapse prior to the stone itself collapses.

Mortar (Type S): This type of mortar contains a minimum of 1800 psi. It contains medium strength, and defined as (Type S). It is mostly utilized for outside structures like a patio as well as exterior walls which are assessed below grade as it is more durable as compared to (type N). Therefore, it is best suited to perform with mildly withstanding soil pressures below grade.

Applications - Below grade having normal to moderate loading. In some areas where the masonry touches the ground, like paving or shallow retaining walls.

Mortar (Type N) for general purposes: Mortar (Type N) is mostly recognized mortar. This type of mortar is utilized when there exist no other special circumstances which need a specialty for the load bearing of a structure. It has medium strength (minimum 750 psi) and is suitable for reinforced interior and above-grade exterior load-bearing walls. It is perfect for semi-soft stone or masonry as it will bend in excess of a high-strength mortar to resist prevents cracking of the masonry units.

Mortar (Type O): Mortar (Type O) refers to a mortar that contains a low strength (a minimum of 350 psi). This type of mortar is useful for interior usages where non-load bearing exist. It is frequently applied to patch mortar where the wall has strong structure. Type O mortar is occasionally applied with masonry units having a low compressive strength (i.e. sandstone or brownstone) to allow more flexibility for resisting cracks in the units.

Applications: Interior non-load-bearing areas with very restricted exterior use because of its low structural capacity and not suitable for the areas prone to high winds. Type O Mortar mix is perfect when repointing because of its stability. It is applied in above grade, non-load bearing situations preferably in interior environments.

Mortar (Type K): The (Type K) Mortar is not listed under the ASTM C 270 anymore, although it is still applicable to projects which have a pre-historic preservation need. This type of mortar will not produce any damage to a fragile structure, nor to any fragile stones as it contains the lowest compressive strength of any mortar.

Applications : Mortar (Type K) is useful for safeguarding pre-historic structures, which needs the use of a low strength mortar to get rid of any damage. Type K is not recommended for load bearing.

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Published By
Rajib Dey
www.constructioncost.co
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