What is the difference between type s and m mortar

Type S has high compressive strength psi but adds high tensile bond strength. Type S mortars are required to have a minimum of psi and their mixes usually give you strengths ranging between and psi. This type of mortar performs well while fighting soil pressure and wind, or while under seismic conditions.

Type S contains 2 parts portland cement, 1 part hydrated lime and 9 parts sand. Type N is described as a general purpose mortar mix and can be used in above grade, exterior and interior load-bearing installations. It is also associated most commonly with soft stone masonry. Type M is a high-strength mortar that may be considered for load bearing or demanding freeze-thaw applications.

Type O is a low-strength mortar that is sometimes used for interior masonry or repointing. ASTM C provides two alternatives for specifying mortars: proportion specifications and property specifications.

Under the proportion specifications, mortar ingredients must meet indicated product standards and be volumetrically proportioned within limits. No physical requirements are placed on the mortar itself. Under the property specifications, in addition to meeting the individual product standards, mortar materials mixed in the laboratory using job site proportions must meet certain property requirements.

Either the proportion specifications or the property specifications should be selected, not both. If project specifications do not indicate which has been selected, the proportion specifications govern, unless data qualifying the mortar under the property specification are presented to and accepted by the specifier.

It should be understood that the property requirements of ASTM C are for laboratory specimens and are not for field quality control. The ASTM standard presumes that the proportions developed in the laboratory to meet the property requirements will result in satisfactory performance in the field. Field testing is not required, and if field testing of compressive strength is conducted, results are not required or expected to meet the minimum compressive strength requirements of the property specifications.

Mortar Materials ASTM C places requirements on component mortar materials water, sand, cementitious materials, and possibly admixtures. It is important to understand the contribution of each component material to the performance of mortar. Water acts as a lubricant in the plastic mortar and is required for hydration of the cement. Strength gain of mortar is not related to evaporation of water but to the chemical combination of water with cement compounds in the mortar.

Since some mixing water is lost to absorptive units and evaporation, the maximum amount of water consistent with optimum workability should be added to mortar. Masonry sand provides the basic "framework" for mortar. Sand particles are coated and lubricated by the mortar paste to provide body and flowability required in the plastic mortar and are bonded together as the paste hardens to provide required structural properties.

Sand quality affects both workability characteristics of plastic mortar and properties of hardened mortar such as compressive strength, bond strength, and drying shrinkage. Masonry cement is a hydraulic cement, that is, it hardens by chemically reacting with water and will do so under water.

It consists of portland or blended cement and inorganic plasticizing materials such as pulverized limestone, hydrated or hydraulic lime together with other agents introduced to optimize workability, board life and water retention, contribute to improved durability; and reduce drying shrinkage and water absorption of mortar.

Mortar cement is a relatively new product designed for use in demanding structural masonry applications. Mortar cement, like masonry cement, is a hydraulic cement, primarily used to produce masonry mortar. However, mortar cement must meet lower maximum air content limits than masonry cement and is the only mortar material or system that has minimum bond strength requirements.

Whether present as an integral part of masonry cement or as a separate ingredient added at the mixer with hydrated lime, portland cement acts as the glue, which holds the mortar and, ultimately, the masonry, together.

Compressive strength and bond strength are related to the portland cement content of mortar. A balance of compressive strength, flexural strength, and adhesion is required for a high quality installation. Type M mortar is the highest strength mortar minimum psi and should only be used where significant compressive strength is required.

This type of mortar is generally used with hard stone. Since it closely mimics the strength of stone, it will not fail before the stone itself fails.

Type M mortar is less workable than other types so it should only be specified when needed. It also lack good adhesion so it may not seal properly. Type M Mortar Uses: Below grade applications where extreme gravity or lateral loads are present, such as in retaining walls. In conjunction with hard stone or other masonry units that have a high compressive strength.

Type S mortar is a medium-strength mortar minimum psi. Since it is stronger than Type N, it can be used for below-grade exterior walls and other exterior projects projects like patios. In addition, it has higher bonding and lateral strength than type N, which makes it a good choice for resisting moderate soil pressures below grade.

Type S Mortar Uses: Below grade applications with normal to moderate loading. Locations where the masonry is in contact with the ground, such as paving or shallow retaining walls. Type N is the most common type of mortar and is the best all-around selection unless special characteristics are required.

It is medium strength minimum psi and is meant for reinforced interior and above-grade exterior load-bearing walls. It is great for semi-soft stone or masonry since it will flex more than a high-strength mortar — this prevents cracking of the masonry units. Type N Mortar Uses: General purpose applications above grade where normal loading occurs. Type O mortar is a low strength mortar minimum psi that is used in non-load-bearing interior applications.

It is easy to work with so it is often used to repair mortar where the wall is structurally sound. Type O mortar is sometimes used with masonry units that have a low compressive strength i. Type O Mortar Uses: Interior non-load-bearing applications with very limited exterior use.

Repointing where the structural integrity of the wall is intact.