Method for the Production of Portland Cement Composition with Low Embodied Energy and Carbon for Abrasion Resistant Concrete and Mortar

Abstract

Portland cement has high embodied energy and embodied carbon associated with its manufacture. In many construction applications, the need for concrete and mortar abrasion resistance requires the consumption of significantly higher amounts of Portland cement for higher concrete and mortar compressive strength. The invention comprises a new method for producing a chemically inert, low embodied energy and carbon mineral additive, with specific hardness and particle size, during Portland cement manufacturing that replaces a significant portion of the Portland cement by mass in the final composition. Alternatively, the mineral additive is produced separately and combined with Portland cement. The resulting mineral additive Portland cement composition has significantly lower embodied energy and carbon and imparts significantly higher abrasion resistance to concrete and mortar.

Claims

1. A mineral additive derived from a hard mineral raw material, for use with Portland cement in formation of a cement composition, the mineral additive comprising: the mineral additive being (i) substantially chemically inert in an aqueous Portland cement environment, (ii) substantially non-hydraulic, and (iii) substantially non-pozzolanic; the mineral additive having a Mohs hardness of 7.0 or more; and the mineral additive comprising a particulate material having a median particle size ranging from 4 to 800 microns.

2. The mineral additive according to claim 1 wherein the mineral additive has a median particle size ranging from 10 to 400 microns.

3. The mineral additive according to claim 1 in combination with the Portland cement so as to form the cement composition, wherein a mass of the mineral additive within the cement composition is 5 to 50% of a total mass of the Portland cement and the mineral additive in the cement composition.

4. A cement composition comprising: Portland cement; and a mineral additive derived from a hard mineral raw material; the mineral additive being (i) substantially chemically inert in an aqueous Portland cement environment, (ii) substantially non-hydraulic, and (iii) substantially non-pozzolanic; the mineral additive having a Mohs hardness of 7.0 or more; and the mineral additive comprising a particulate material having a median particle size ranging from 4 to 800 microns.

5. The cement composition according to claim 4 wherein a mass of the mineral additive within the cement composition is 5 to 50% of a total mass of the Portland cement and the mineral additive in the cement composition.

6. The cement composition according to claim 5 wherein the cement composition consists only of the Portland cement and the mineral additive.

7. The cement composition according to claim 5 wherein the cement composition further comprises a mineral dispersing agent comprised of a chemical which controls the pH and electrical surface charge of the mineral particles, the mineral dispersing agent having a mass that is 1 to 3% of a total mass of the Portland cement, the mineral additive and the mineral dispersing agent in the cement composition.

8. The cement composition according to claim 4 wherein the hard mineral raw material has less than or equal to 1.0% moisture by mass and is added to Portland cement clinker prior to clinker finish grinding, the hard mineral raw material being comminuted with clinker and gypsum on dry basis and the mineral additive is produced during clinker finish grinding.

9. The cement composition according to claim 4 wherein the hard mineral raw material is comminuted on a dry basis separately from the Portland cement to produce the mineral additive with less than 1.0% moisture by mass, and mineral additive is added to and mixed with the Portland cement subsequently to being comminuted.

10. The cement composition according to claim 4 wherein the hard mineral raw material is comminuted on a wet basis separately from the Portland cement to produce the mineral additive with less than 1.0% moisture by mass, and mineral additive is added to and mixed with the Portland cement subsequently to being comminuted.

11. A method for producing a Portland cement composition from mineral raw materials comprising: comminuting the mineral raw material to obtain a mineral additive such that a median particle size of the mineral additive ranges from 4 to 800 microns; adding the mineral raw material to Portland cement prior to comminution or adding the mineral additive to Portland cement after comminution to form the Portland cement composition such that a mass of the mineral additive within the cement composition is 5 to 50% of a total mass of the Portland cement and the mineral additive in the cement composition; sourcing the mineral raw material prior to comminution from natural sources, industrial by-products or synthetic manufacturing such that: the mineral additive is (i) substantially chemically inert in an aqueous Portland cement environment, (ii) substantially non-hydraulic, and (iii) substantially non-pozzolanic; and the mineral additive has a Mohs hardness of 7.0 or more.

12. The method according to claim 11 including forming the mineral additive such that the mineral additive has an embodied energy less than 4.0 GJ per tonne of mineral additive.

13. The method according to claim 11 including forming the mineral additive such that the mineral additive has an embodied energy less than 2.0 GJ per tonne of mineral additive.

14. The method according to claim 11 including forming the mineral additive such that the mineral additive has an embodied carbon less than 0.8 tonnes CO.sub.2 equivalent per tonne of mineral additive.

15. The method according to claim 11 including forming the mineral additive such that the mineral additive has an embodied carbon less than 0.4 tonnes CO.sub.2 equivalent per tonne of mineral additive.

16. The method according to claim 11 wherein the mineral raw material is added to clinker, in the required dosage, during Portland cement production and the mineral additive is produced during the finish grinding of clinker and gypsum.

17. The method according to claim 16 wherein the mineral raw material is substantially dry, prior to intergrinding with the clinker.

18. The method according to claim 11 wherein the mineral raw material is comminuted separately from the Portland cement to produce the mineral additive and the mineral additive is then mixed with the Portland cement in the required dosage.

19. The method according to claim 18 wherein the mineral additive is substantially dry, prior to mixing with the Portland cement.

20. The method according to claim 11 wherein the cement composition further comprises a mineral dispersing agent comprised of a chemical which controls the pH and electrical surface charge of the mineral particles, the mineral dispersing agent having a mass that is 1 to 3% of a total mass of the Portland cement, the mineral additive and the mineral dispersing agent in the cement composition.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0093] Some embodiments of the invention will now be described in conjunction with the accompanying drawings in which:

[0094] FIG. 1a is a flowchart illustrating the preferred embodiment of the invention method.

[0095] FIGS. 1b and 1c are flowcharts illustrating alternative embodiments of the invention method.

[0096] FIG. 2 is a graph demonstrating the increase in mortar abrasion resistance over the required particle size ranges of several hard mineral additive examples, relative to increased Portland cement content.

[0097] FIG. 3 is a graph demonstrating the chemical inertness of several mineral additive examples, based on compressive strength of mortar, relative to increased Portland cement content.

[0098] FIG. 4 is a graph demonstrating the embodied energy and carbon of several mineral additive examples over the required particle size ranges.

[0099] FIG. 5 is a graph demonstrating the reduction in embodied energy and carbon of the Portland cement composition made with one example mineral additive.

[0100] FIG. 6 is a graph demonstrating the reduction in concrete embodied energy using one example mineral additive Portland cement composition.

[0101] FIG. 7 is a graph demonstrating the reduction in concrete embodied carbon using one example mineral additive Portland cement composition.

[0102] FIG. 8 is graph demonstrating the increase in mortar abrasion resistance with example mineral additive Portland cement compositions in the required particle size range, relative to two surface applied hardeners.

[0103] In the drawings like characters of reference indicate corresponding parts in the different figures.

DETAILED DESCRIPTION

[0104] By experimentation, the inventor has determined the following:

[0105] Chemical Inertness: minerals that do not significantly chemically react in aqueous Portland cement environment, are not substantially hydraulic and are not substantially pozzolanic, are required so as not to be chemically consumed and converted into conventional CSH gel with limited abrasion resistance.

[0106] Hardness: during abrasion, chemically inert minerals with a sufficiently high hardness resist penetration of impinging materials into the concrete or mortar surface. Sufficiently hard minerals have a Mohs hardness of at least 7.0.

[0107] Particle Size: chemically inert, hard minerals must have particle size in a required and preferred range for the following reasons:

[0108] Enhanced Hardness: Minerals are conglomerates of smaller, discrete particles fused together inside coarser particles. Planes and points of weakness exist inside the conglomerates between the smaller, discrete particles that reduce the hardness of the conglomerates (i.e.: grain boundaries, pores, fissures, cracks). The mineral conglomerates must be fractured along the planes of weakness and reduced to discrete particles with sufficient hardness to effectively resist abrasion in concrete and mortar.

[0109] Dispersion: the discrete particles must be present in sufficient number and size to blend evenly among the cement particles during mixing and disperse uniformly through the cementitious material matrix to most effectively increase the abrasion resistance of Portland cement, concrete and mortar.

[0110] Embodied Energy and Carbon: comminution consumes energy and increases exponentially at very fine particle sizes, which increases the mineral additive embodied energy and carbon.

[0111] The required particle size range is 4 to 800 microns median particle size or d.sub.50 (0.004 to 0.800 mm, or 0.00016 to 0.031 inches). The preferred particle size is 10 to 400 microns median particle size of d.sub.50 (0.010 to 0.400 mm, or 0.0004 to 0.016 inches).

[0112] Particle Size Reduction: in the event the particles are not naturally in the required or preferred size range, comminution of the minerals by crushing or grinding is utilized. Mineral comminution to the required or preferred particle size distribution can be performed as follows:

[0113] During Cement Manufacturing (the preferred embodiment): Dry, chemically inert, hard minerals can be added to Portland cement clinker and comminuted during cement finish grinding.

[0114] Blended with Portland Cement (alternative embodiments): Alternatively, the mineral can be comminuted separately by crushing and/or grinding on a dry basis and mixed with finished Portland cement. Alternatively, the mineral can be comminuted on a wet basis, dried and then mixed with finished Portland cement.

[0115] Energy Consumption: Other than the energy required for comminution, the only other mineral processing energy required may be: low energy drying of the hard mineral before dry intergrinding with clinker or dry mixing with cement, in the event the mineral has moisture content more than 1% by mass. In contrast to clinker manufacturing, no calcination or energy intensive thermal processing of the hard minerals is required. Additional energy may also consumed during transportation of the hard mineral to the comminution facility in the event comminution is not performed at the same location as the hard mineral. Therefore, mineral additives produced will have substantially lower embodied energy and carbon than Portland cement.

[0116] Dosage: mineral additives produced in the above fashion can replace up to 50% by mass of clinker in Portland cement or 50% by mass of Portland cement in the cement composition, reducing the embodied energy and carbon and increasing the abrasion resistance of the Portland cement, concrete or mortar.

[0117] Optional Dispersing Agent: some mineral particles are prone to develop surface electrical charges that increase their propensity to agglomerate with each other or Portland cement particles, which impedes their dispersion in the concrete or mortar mixture. In such cases, it is desirable to include a dispersing agent in the Portland cement composition to facilitate dispersion of the mineral additive throughout the cementitious material matrix.

[0118] In this section, three digit reference numbers (i.e.: 004) in bold correspond to reference points on the drawings as noted.

[0119] FIG. 1a: illustrates the preferred embodiment of the invention, which comprises intergrinding the raw mineral material during Portland cement manufacturing (finish grinding) including the following elements and steps:

[0120] 001, 002 Chemical Reactivity, Hardness: the mineral raw materials used must be substantially chemically inert in an aqueous Portland cement environment and have a Mohs hardness of at least 7.0.

[0121] 003, 004 Moisture Content, Drying: if the mineral raw material has less than or equal to 1.0% moisture by mass, it can be directly added to clinker. If the mineral raw material has more than 1.0% moisture by mass it must be dried, prior to adding to clinker.

[0122] 005 Dry Comminution: the mineral additive is produced by dry comminution during the cement finish grinding process, by intergrinding with clinker and gypsum and optionally, a dispersing agent. The mineral additive is comminuted to the required or preferred particle size range.

[0123] 006 Portland Cement Composition: the final Portland cement composition contains finished Portland cement, with mineral additive in the amount of 5% to 50% by mass of the total composition.

[0124] FIG. 1b illustrates an alternative embodiment of the invention, which comprises comminuting the mineral raw material separately on its own on a dry basis 007 to produce the mineral additive and mixing the mineral additive with Portland cement 008. Optionally a dispersing agent may be added during dry comminution 007 or mixing with Portland cement 008.

[0125] FIG. 1c illustrates an alternative embodiment of the invention, which comprises comminuting the mineral raw material separately on its own on a wet basis by forming a slurry with water to produce the mineral additive 009, drying the mineral additive to less than or equal to 1.0% by mass 010 and blending the mineral additive with Portland cement. Optionally a dispersing agent may be added during wet comminution 009 or mixing with Portland cement 008.

[0126] According to FIG. 2 example mineral raw materials were comminuted to the median particle size range shown in FIG. 2, using a 12.4 L, 0.5 hp bench scale ceramic ball mill. The following examples of mineral raw materials were comminuted as follows:

[0127] Emery (Corundite) 012: a natural mineral mixture of corundum (Mohs hardness=9.0), spinel (Mohs hardness=8.0) and magnetite (Mohs hardness=6.0). The overall hardness of emery is 8.5.

[0128] Lead-Zinc Slag 013: a granulated mineral by-product of lead and zinc metal pyrometallurgical smelting. The Mohs hardness of the lead-zinc slag is 7.0.

[0129] Nickel Slag 014: a granulated mineral by-product of nickel metal pyrometallurgical smelting. The Mohs hardness of the nickel slag is 7.0.

[0130] Copper Slag 015: a granulated mineral by-product of copper metal pyrometallurgical smelting. The Mohs hardness of the copper slag is 7.0

[0131] Natural Alluvial Sand 016: a natural mineral mixture of feldspar (Mohs hardness=6 to 6.5) and quartz (Mohs hardness=7.0). The overall hardness of the sand is 6.6.

[0132] The median comminuted particle size was measured as the equivalent spherical particle size by conventional laser diffraction. Alternatively, median particle size can be measured by conventional sieve analysis, zeta potential analysis, electric sensing zone analysis, spectroscopy, microscopy or digital image processing. The median particle size can also be estimated from the specific surface area (fineness) of the comminuted mineral, measured using conventional means such as air permeability measurement (i.e.: Blaine fineness) or inert gas adsorption (i.e.: Brunauer-Emmett-Teller (BET) fineness.)

[0133] On average, concrete mixtures will contain on the order of 250 to 300 kg of Portland cement per m.sup.3 of concrete. A control mortar mixture (with no mineral additive) was established by removing the coarse aggregate from a concrete mixture with approximately 290 kgs of Portland cement per m.sup.3 of concrete. Mortar, with no coarse aggregate, comprises the outermost surface of the concrete initially exposed to abrasion in construction applications. The control mixture had the following proportions:

[0134] Conventional Portland cement: 645 kg/m.sup.3 of mortar.

[0135] Sand: 1,377 kg/m.sup.3 of mortar.

[0136] Water: 253 kg/m.sup.3 of mortar.

[0137] Water Reducing Admixture: polycarboxylate high range water reducer at 0.4% by mass of Portland cement composition.

[0138] Comminuted mineral additives were mixed with Portland cement in the proportions of 80% Portland cement and 20% mineral additive by mass and the mineral additive Portland cement composition was used to make mortar test mixes with the following proportions:

[0139] Test Portland Cement Compositions: 645 kg/m.sup.3 of mortar (516 kg Portland cement, 129 kg mineral additive.)

[0140] Sand: ranged from 1,359 to 1,393 kg/m.sup.3 of mortar to yield equivalent mix volume.

[0141] Water: 253 kg/m.sup.3 of mortar.

[0142] Water Reducer Admixture: polycarboxylate high range water reducer at 0.3% to 0.4% by mass of Portland cement composition, varied as required to maintain mortar workability within 20% of control mixture.

[0143] Mortar test specimens measuring 102 mm wide102 mm long16 mm thick (4-inch4-inch0.625 inch) were cast from each mixture, given a smooth steel trowel finish by hand, wet cured at 15 to 20 C. (59 to 68 F.) for 26 days and air cured for 2 days, prior to abrasion resistance testing.

[0144] Abrasion resistance of mortar test specimens was tested with a rotary platform abraser consistent with ASTM C1803-15: Standard Guide for the Abrasion Resistance of Mortar Surfaces Using a Rotary Platform Abraser as this test method directly tests the abrasion resistance of the mortar, which comprises the outermost concrete surface. The abrasion resistance of concrete can also be measured utilizing any standard procedure including: ASTM C 418 Standard Test Method for the Abrasion Resistance of Concrete by Sandblasting, ASTM C 779 Standard Test Method for Abrasion Resistance of Horizontal Concrete Surfaces (Procedures A, B or C), ASTM C 944/944M Standard Test Method for Abrasion Resistance of Concrete or Mortar Surfaces by the Rotating-Cutter Method, ASTM C 1138M Standard Test Method for the Abrasion Resistance of Concrete (Underwater Method), ASTM C627: Standard Test Method for Evaluating Ceramic Floor Tile Installation Systems Using the Robinson-Type Floor Tester (modified for concrete abrasion resistance testing), BS EN 13892-4 Methods of test for Screed materialsPart 4: Determination of Wear Resistance-BCA (standard test method in the United Kingdom), or DIN 52108 Testing of Inorganic Non-Metallic MaterialsWear test Using the Grinding Wheel According to BoehmeGrinding Wheel Method (standard test method in Germany.)

[0145] The relative change (% increase or decrease) in test specimen abrasion resistance is calculated relative to the control specimen based on the abrasive wear measured by any of the above tests. Abrasive wear may be measured as the specimen mass loss, depth of wear, volume of wear or rate of wear over the duration of the test, as per the standard test methodology. The change in test specimen abrasion resistance relative to the control is calculated as follows:

[00001]$\mathrm{Relative}.Math..Math.\mathrm{Abrasion}.Math..Math.\mathrm{Resistance}.Math..Math.\mathrm{Change}.Math.=\frac{\mathrm{AWcontrol}}{\mathrm{AWtest}}-1$

[0146] Where AW=the abrasive wear measured during the test.

[0147] As seen in FIG. 2, alluvial sand 016 with a Mohs hardness less than 7.0 cannot replace Portland cement without reducing mortar abrasion resistance, relative to the control mixture with 20% more Portland cement. Minerals with Mohs hardness of 7.0 or more replaced 20% of Portland cement by mass and significantly increased mortar abrasion resistance when comminuted to the required particle size range 017 of 4 to 800 microns median particle size d.sub.50 (0.004 to 0.800 mm, or 0.00016 to 0.031 inches).

[0148] The preferred particle size range 018 is 10 to 400 microns (0.010 to 0.400 mm, or 0.0004 to 0.016 inches) median particle size (d.sub.50), which encompasses the optimum performance range that yields mineral additives with lower embodied energy and carbon (see FIG. 4) and high abrasion resistance performance (see FIG. 2).

[0149] FIG. 3 demonstrates the substantial chemical inertness of the mineral additives in the required and preferred particle size range with example mineral additives derived from lead-zinc slag 019, copper slag 020, emery 021 and alluvial sand 022. Relative to the control mixture with 20% more Portland cement by mass, the mineral additives in the required particle size range do not demonstrate significant hydraulic or pozzolanic reactivity contributing to mortar compressive strength development.

[0150] FIG. 4 demonstrates the embodied energy and carbon of example mineral additives produced to the required and preferred median particle size range. The embodied energy is determined as follows:

[0151] Comminution Energy: is the shaft power of the full scale comminution energy input per unit mass of mineral raw material comminuted. In FIG. 4, for example: shaft power is determined by measuring the electric motor current draw and voltage of a 12.4 litre, 0.5 hp bench scale ball mill, calculating shaft power by conventional means, then multiplying the shaft power by the grinding time and dividing by the mass of material comminuted in kilograms. The full scale grinding energy is calculated by multiplying the bench scale comminution energy by a correlation coefficient, which has been determined by the inventor to correlate with full scale grinding energy consumption based on experience and experimentation. Other conventional means of measuring comminution energy are also suitable.

[0152] Transportation Energy: In FIG. 4, for example: mineral raw material transportation by diesel dump truck over a distance of 300 km (186 miles) is assumed. According to Portland Cement Association, a diesel dump truck will consume approximately 338 KJ/tonne.km according to [M. Marceau, M. Nisbet and M. VanGeem, Life Cyle Inventory of Portland Cement Manufacture, Portland Cement Association, Skokie, Ill., 2006]. The transportation fuel energy consumption is estimated at 0.1 GJ/tonne.

[0153] Drying Energy: the mineral raw material has less than 1.0% moisture content by mass and drying energy consumption is not required.

[0154] As seen in FIG. 4 example mineral additives produced to the required particle size range have less embodied energy than Portland cement 023. Example minerals produced to the preferred particle size range have substantially less embodied energy than Portland cement (less than approximately 25% of embodied energy.)

[0155] The mineral additive embodied carbon is determined as follows:

[0156] Electricity GHG Emissions: According to Canada's National Energy Board, electricity generation in the Canadian Province of Alberta emits on average, 790 g of CO.sub.2/kW.h (231 kg of CO.sub.2 eq per GJ) according to [NEB, NEBCanada's Renewable Power, 2019. (Online). Available: https://www.neb-one.gc.ca/nrg/sttstc/lctrct/rprt/2017cndrnwblpwr/ghgmssn-eng.html?=undefined&wbdisable=true. (Accessed 13 Jan. 2019)]. Alberta's power supply is primarily coal fired and has the highest GHG emission intensity in Canada. In FIG. 4, the electrical power consumption during comminution is multiplied by the emission intensity of local power production.

[0157] Transportation Emissions: According to the US Energy Information Administration, diesel fuel combustion emits 161.3 lbs of CO.sub.2/MBtu (73 kg CO.sub.2 eq per GJ) according to [EIA, How much carbon dioxide is produced when different fuels are burned?, 2019. (Online). Available: https://www.eia.gov/tools/faqs/faq.php?id=73&t=11. (Accessed 13 January 2019)]. In FIG. 4 the diesel emissions during transportation are calculated as 0.0074 tonnes of CO.sub.2 eq per tonne of mineral additive.

[0158] As seen in FIG. 4, the embodied carbon of the example mineral additives produced to the required particle size range is less than Portland cement 023. Example minerals additives produced to the preferred particle size range have substantially lower embodied carbon than Portland cement (less than approximately 25% of embodied carbon.)

[0159] FIG. 5 demonstrates the reduction of the Portland cement composition (Portland cement plus mineral additive) embodied energy relative to the amount of Portland cement replaced by an example mineral additive produced by comminuting nickel slag to a median particle size of 100 microns. At 20% Portland cement mass replacement by hard mineral 025, the embodied energy is reduced to 3.85 GJ/tonne, which is approximately 20% lower than Portland cement on its own. At 50% Portland cement mass replacement, the blended cement embodied energy is reduced to 2.47 GJ/tonne, which is approximately 49% lower than Portland cement on its own.

[0160] FIG. 5 also demonstrates the reduction of the Portland cement composition (Portland cement plus mineral additive) embodied carbon relative to the amount of Portland cement replaced by an example mineral additive produced by comminuting nickel slag to a median particle size of 100 microns. At 20% Portland cement mass replacement by hard mineral 026, the embodied carbon is reduced to 0.75 tonnes of CO.sub.2 eq per tonne of binder, which approximately 20% lower than Portland cement on its own. At 50% Portland cement mass replacement, the binder embodied carbon is reduced to 0.47 tonnes of CO.sub.2 eq per tonne of binder, which is approximately 49% lower than Portland cement on its own.

[0161] FIG. 6 demonstrates the reduction of the embodied energy of concrete containing the Portland cement composition with an example mineral additive produced by comminuting nickel slag to a median particle size of 100 microns. Concrete with a typical cement content of 275 kg/m.sup.3 of concrete 027, with 15% Portland cement by mass replaced mineral additive has an embodied energy of 1.18 GJ/m.sup.3, which is approximately 14% lower than concrete without mineral additive. At 50% replacement of Portland cement with mineral additive, the embodied energy of the concrete is 0.74 GJ/m.sup.3, which is approximately 47% lower than concrete without mineral additive.

[0162] FIG. 7 demonstrates the reduction of the embodied carbon of concrete the Portland cement composition with an example mineral additive produced by comminuting nickel slag to a median particle size of 100 microns. Concrete with a typical cement content of 275 kg/m.sup.3 of concrete 028, with 15% Portland cement by mass replaced by mineral additive has embodied carbon of 0.225 tonnes of CO.sub.2 eq per m.sup.3 of concrete, which is approximately 14% lower than concrete without mineral additive. At 50% replacement of Portland cement with mineral additive, the embodied carbon of the concrete is 0.14 tonnes of CO.sub.2 eq per m.sup.3 of concrete, which is approximately 46% lower than concrete without mineral additive.

[0163] FIG. 8 demonstrates the effectiveness of the Portland cement composition with example mineral additives, relative to dry shake surface hardeners. The premium dry shake hardener 034 is significantly more expensive than the economy dry shake hardener 033 and is intended for heavy duty abrasion applications. At the manufacturer recommended dosage (1 lb/ft.sup.2 of area), the dry shake hardeners were mixed with the control mortar mix in equal parts by mass, consistent with the practice of working the product into the surface of concrete flatwork mortar. As seen in FIG. 8, the Portland cement compositions with emery 029, lead-zinc slag 030 and nickel slag 031 mineral additives exhibited at least the same, to more typically, substantially higher mortar abrasion resistance as surface applied hardeners, while replacing 20% of the mortar Portland cement by mass, compared to no Portland cement replaced by the surface applied hardener. Additionally, the mineral additive Portland cement compositions are more versatile, compatible and requires no field application labour and schedule. As seen in FIG. 8, alluvial sand 032 does not have sufficient hardness to replace cement and increase mortar abrasion resistance.

[0164] Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.