About Masonry:                       Free.   source: www.MyMason.ca

      Cement Types

        Portland cement
        Used to make concrete, mortar, stucco, and some grouts.
        The aggregates, sand/gravel, add volume and minimize shrinkage in curing.
        Portland cement was not manufactured in the United States until 1871.
        Not to be in contact with soils or ground water.

        White Portland cement
        White Portland cement with white aggregates (ie. sand) produces an extended decorative range.
        Higher potential strength also helps to counteract the strength-diminishing effects of pigment addition.

        N-Type Masonry Cement
        Masonry cement is of a mix of portland cement or blended hydraulic cement and plasticizing lime or other materials.
        Type N has a softer compression strength (~ 750 psi)
        Other materials are included to improve setting time, durability, workability, and water retention.
        It does not have the strength of Type M or Type S mortar.
        Chimneys and walls well above grade, without heavy loads.

        Type M has the highest proportion of portland cement, with 3 parts portland cement, 1 part lime and 12 parts sand.
        Type M has a high compression strength (> 2500 psi) and is used for walls bearing heavy loads.
        Also for below-grade masonry in contact with the earth: foundations, retaining walls, sidewalks and driveways.
        Type M and S are usually interchangeable. Type M is less workable.

        Type S is used in all load-bearing structures unless only Type M is specified.
        Type S has a mid-level compression strength (~ 1800 psi), higher than type N.
        A good general-purpose mortar used in above-grade exteriors exposed to severe weathering.
        Also for below-grade masonry in contact with the earth: foundations, retaining walls. etc..
        Type S mortars have high relative levels of plasticity and tensile strength.
        When cracks form, the hydrated lime reacts with the air to to produce limestone to fill spaces.

        Refractory Mortar: 2 types:
        Pre-mixed refractory mortar, and, Hydraulically-setting refractory mortar.
        Refractory mortar is made with aggregates that don't expand and tear the mortar apart when heated.
        Premix dries out, rather than cures by chemical reaction as hydraulic mortar does.
        Premix is made with sodium silicate as a binder which does not deteriorate with heat.
        With premix one can make very thin joints, and needn't pre-soak the firebrick.
        Hydraulic refractory mortar should be used for outdoor fireplaces, to set ceramic flue liners,
        to parge the throat and smoke chamber, and also to lay pre-wetted firebrick.

        Parging Cement
        More expensive as a pre-mix, but the pre-mix allows masons to use a common product to help match blends.
        Parging cement includes bonding agents to help adhere to the wall.
        A pre-cement bonding agent can be applied to the wall, to protect the concrete and help adherence.

        Self-Leveling Cement
        $44 per bag at Home Depot, covering 20 s.f. at 1/4", plus primer. Optimally applied with one coherent top coat.
        Can be used as a subflooring for tiles, carpet, and other floor surfaces.
        Can be applied over concrete, wood, steel, ceramic tile and other sound, rigid flooring.
        Takes foot traffic after 6 to 8 hours.

        Hydraulic Cement
        A mixture of sand, cement and special additives designed to stop the flow of water through leaks.
        It will even stop leaks underwater and under pressure.

        Delivered by Mixer Truck, the first cubic yard is the most expensive, approx. $750.00
        In Bags: Concrete can be found in various formulations in bags.
        Colour can be added, some colours being more expensive than others.
        A solid base for walking or driving surfaces is most important to long term success.
        There are concrete for various applications, from garage floors, patching, support posts, etc..

        The sand can range in colour, from whites through browns to greys, even beyond.
        Stones can range in size and colour. Small sizes can be used in mortar for pointing.
        Adding dyes to the cement finds the colour range expanded by the sand colour.


        A note about Curing, Concrete
        The range of probable drying conditions can be forecast for a given locale based on typical range of weather conditions
        and projected concrete temperatures. Drying rates of greater than 0.3 kg/m2/h may present a problem.

        The Equation.
        Evaporation rate of concrete's bleed water - the effect of environmental conditions.

        ER = evaporation rate (kg/m2/h)
        WS = the wind speed (m/s)
        CT = concrete temperature (C)
        AT = air temperature (C)
        RH = relative humidity (%)



        source of equation: http://www.fhwa.dot.gov/pavement/pccp/pubs/02099/chapt2.cfm#fig4


        and for Lafarge's guide to masonry cements,click here.