PRODUCT DATA SHEET

Hydro-Guard

 

INTRODUCTION   Hydro-Guard, a co-polymer, has been specifically designed as a  admixture for use in cementisious compositions.   Typical properties of Hydro-Guard are as follows :-               total solids content        approx 47%             pH                               11.0             viscosity                       100 cps (Brookfield LVT spindle no 2 at 60 rpm (20º C)            specific gravity  1.0             freeze/thaw stability       good (see also under “Storage of Hydro-Guard”)   The addition of Hydro-Guard confers numerous advantages over untreated mortars and concretes, such as :- ·        greatly improved adhesion to substrates, including dense impervious concrete ·        excellent resistance to water and water vapour ·        improved toughness and flexibility ·        better resistance to frost ·        improved resistance to certain chemicals ·        diminishing dusting   SUGGESTED USES Cement compositions containing Hydro-Guard are particularly useful in a number of applications.  Some examples are :- ·                    water-resistant rendering for interior or exterior walls or basements ·                    damp-resistant layers ·                    levelling floors prior to laying tiles, wood blocks, etc ·                    patching and repairing concreted areas

T E C H N I C A L     I N F O R M A T I O N

SALES                                                                                                                                                                    PRODUCTION

Cosmo-Dec Tel 27 31 776 3439 Fax 086 680 7986

Information provided is based on laboratory evaluations and data believed to be reliable.  Recommendations are given in good faith but without warranty.  It is the user’s responsibility to determine the suitability for his own use.  Freedom from patent restrictions must not be assumed.  Our standard conditions of sale apply to all orders.

 

continued / ..............

 

·                    waterproof flat roofing and balconies

·                    industrial flooring, screeding and topping

·                    nosing for stairs indoors/outdoors

·                    flooring for dairies, food factories, fertiliser stores where improved chemical resistance is required

·                    lining of effluent ducts, tunnels and canals

·                    corrosion protection of steel reinforcing rods in concrete and of steel structures

·                    water-resistant adhesives for tiles, aggregates, glass, steel, etc

·                    screeds for bathrooms and showers

 

STORAGE

·      HYDRO-GUARD can be stored for 6 months in closed, unopened original drums or storage vessels, provided the temperature does not fall below 5°C or exceed 40°C.

·      Keep out of direct sunlight and protect from frost.

 

Aggregate

Washed sharp sand, free from excessive fibres, should always be used in Hydro-Guard-modified cement mortars.  Where a very smooth surface is required a fine sand may be used, but it is important to ensure that there are no very fine clay-like particles present.  Many types of aggregate have been successfully used in Hydro-Guard modified compositions; typical examples are those conforming to the SABS 1090 - 1976 “Sand for plaster and mortar” as well as granite chippings used in heavy duty flooring.

 

Workability

The workability time is generally slightly increased by the addition of Hydro-Guard.  In cold weather conditions (ie below 10º C) especially when it is also damp, it is desirable to use a rapid or extra-rapid hardening cement.  Alternatively, ordinary Portland cement may be used in conjunction with 2% - 4% of calcium chloride (expressed on cement weight); the calcium chloride should be added as a 50% solution in water to the mortar mix.

 

Additives

Workability additives such as fly ash and lime are not necessary as Hydro-Guard exerts a considerable plasticising effect of it’s own.  Air entraining agents should not be used without adequate testing.  The addition of an anti-foaming agent may sometimes be desirable and we have found that Nopco NDW added at the level of 20g per 5 litres of Hydro-Guard is an effective material.

 

Cleaning of equipment

All tools should be cleaned immediately after use because hardened Hydro-Guard-modified cement compositions have excellent adhesion and are therefore difficult to remove.  If this important precaution is overlooked, solvents such as white spirit, solvent naphtha or preferably toluene can be useful in removing hardened Hydro-Guard-modified mortar.

 

Note on anti-foam

For most applications, addition of anti-foam is not normally necessary when using Hydro-Guard.  Occasionally, it may be desirable to incorporate an anti-foam in some Hydro-Guard-modified flooring compositions, eg those containing flint aggregates.  If anti-foam is required, we suggest the addition of Nopco NDW added at the level of 14 g antifoam per 5 litres.

______________________________________________________________________

 

APPLICATION OF HYDRO-GUARD

The next section of this bulletin gives detailed information describing the use of Hydro-Guard modified compositions for walls and floors.  Also included are some recommendations for water-resistant treatments, patching and heavy-duty floorings.  We have extensive knowledge of the use of Hydro-Guard in a host of specialised applications, and we are always pleased to make recommendations for individual requirements.

 

Test results obtained on Hydro-Guard-modified compositions are given in separate test data sheets.

 

WALL RENDERINGS

Preparation

It is necessary to ensure that the wall surface is free from crumbly or other unsound areas.  Dusty patches and old paint should also be removed.  It is usually sufficient to prepare the wall with a wire brush.  All surfaces should be dampened an hour or so before priming.

Priming

The application of a priming coat is normally recommended to obtain maximum adhesion of the subsequently applied rendering.  The priming coat, consisting of 2 parts or ordinary Portland cement slurried with 1 part of Hydro-Guard, should be thoroughly brushed on to the prepared wall surface.

The rendering is applied whilst the priming coat is still wet.

Mixing

A general purpose rendering compositions is as follows :-

            SABS 1090 - 1976 “plaster sand”        100 kgs

            ordinary Portland cement *                     33 kgs

            Hydro-Guard                            6 litres

            water                                                    as required to adjust consistency

* see earlier remarks regarding the use of rapid hardening cements or calcium chloride in   cold weather conditions.

 

NOTE    Although fine sand may be used, especially where a very smooth surface is required, it is essential that there should be no ultra fine clay-like material present in the sand.

 

Mixing should preferably be carried out in a concrete mixer, although hand mixing is permissible where the total weight of the dry batch does not exceed 50 kgs.  The usual procedure is to quickly pre-mix the sand and cement in a mixer, pour in the Hydro-Guard, mix for 2-3 minutes and finally cautiously add water little by little until the required consistency is achieved  over addition of water causes rapid thinning of Hydro-Guard modified mortars owing to the plasticising effect of the Hydro-Guard.

 

Application

The thickness of Hydro-Guard-modified renderings should be restricted to not more than approximately 6mm for each coat.  Greater thickness tends to cause sagging or, in the case of soffits, actual fall off of the unset renderings.  However, several coats may be applied in fairly rapid succession; it is sufficient to allow each coat time to set-off adequately to receive the subsequent coating.  The time required between coats will vary according to conditions but is typically 15 - 30 minutes.

 

A single trowelling operation is usually sufficient  to achieve a moderately smooth finish.  If a smoother surface is required, the rendering should be floated using a clean steel or preferably wooden float after a suitable interval has elapsed.  This interval is usually about ½  to 1 hour, but is best found by experience.

 

WATER RESISTANT RENDERING

Where the main requirement of the rendering is improved water resistance, a modified application technique is recommended.

 

After preparing the substrate as described above, two sealing coats consisting of approximately two parts of Portland cement slurried with 1 part of Hydro-Guard should be thoroughly brushed on to the surface.   The second sealing coat may be applied as soon as the first coat is touch dry, ie after approximately 20 to 30 minutes.  Ideally, the sealing coats should be applied at right angles across each other, thus ensuring complete coverage of the substrate.

 

It is emphasised that the thickness of each sealing coat should not exceed 1.6 mm otherwise crazing may occur.  Before proceeding further, the double sealing coat system must dry out completely for a period of at least 48 hours.

After the sealing coats have dried thoroughly, a tack coat consisting of two parts Portland cement slurried with one part of Hydro-Guard should be applied.  The renderings should then be applied whilst the tack coat is still wet.

 

The amount of Hydro-Guard required in the rendering composition depends upon the degree of water resistance required and the conditions prevailing during application, but the addition of 14 litres of Hydro-Guard per 50 kgs of cement is usually satisfactory.  Where high hydrostatic pressures are anticipated, the level of Hydro-Guard normally recommended is 20 litres per 50 kgs of cement.

 

Because the application of water-resistance rendering is a specialised procedure, we advise each customer to consult us for recommendations appropriate to his individual requirements.

 

FLOOR SCREEDS

 

Preparation

Where the existing floor is old or dirty, it is essential to remove all contaminant such as oil, grease, paint etc to ensure adequate development of bond when the topping is applied.  Any unsound crumbly concrete must also be removed.

 

An efficient way of preparing an old floor is to use a mechanical scabbler to remove all unsound materials.  If the concrete is in reasonably good order light scabbling will suffice, eg to a depth of about 2 - 4 mm.

 

For new floors, to which for example a levelling screed needs to be laid, it may still be desirable to remove the upper surface to ensure that weak surface latence is not present.  Light scabbling to a depth of up to 4mm will normally suffice.  Alternatively good results can often be obtained by etching either new or old concrete floors with hydrochloric acid (1 part of concentrated acid diluted with 2 parts of water) followed by a thorough washing to remove all traces of acid.

If screed bars are to be used to define thickness of the screed, these should be positioned after the above preparation.

 

Priming

The application of a priming coat is normally recommended to obtain maximum adhesion of the subsequently applied screed.  The prepared floor should be thoroughly dampened with water, hosing is suggested, followed by removal of excess standing water.  A priming coat, consisting of 2 parts of ordinary Portland cement slurried with 1 part of Hydro-Guard, would then be thoroughly brushed into the floor using a stiff broom.  The topping is applied whilst the priming coat is still wet.

For general-purpose topping, the following composition is suggested :-

 

SABS 1090 - 1976 “mortar sand”        100 kgs

Ordinary Portland cement                     33 kgs

Hydro-Guard                           6 litres

Water                                                   as required to adjust consistency

The mixing procedure is straight forward, and is as described in the section dealing with wall renderings.

 

Application of topping

Screeds based on the above composition can be laid to any thickness, down to a featheredge if necessary, providing that a sufficiently find grade of sand is used.    However, it is essential that there should be no ultra fine clay-like material present in the sand.

 

Because Hydro-Guard allows “feather-edging” of suitable mortar compositions, it is therefore possible to patch up only the damaged portions of existing concrete floors.  These portions must, of course, be prepared and primed as previously described.

 

After mixing the Hydro-Guard, mortar should be poured over the still wet priming coat and struck off.  It may then be trowelled to the required finish.  An experienced floor layer will readily achieve a finish of satisfactory smoothness without having to do any further trowelling.  However, as an alternative procedure it is possible with care to carry out further trowelling after a suitable interval, when initial stiffening of the mortar has commenced.  A clean steel trowel is recommended for this operation.

 

With a little experience, the correct timing at which this retrowelling should be carried out will be properly judged.  If insufficient time has been allowed to elapse, a thin surface skin will be present over soft unset material and the skin will be torn giving surface cracking.   Too great a time interval on the other hand would result in the mortar having set too much to be smoothed.  The whole surface should be trowelled, not just sections of it to avoid variations in shade, texture, etc.

 

Heavy duty flooring

Hydro-Guard may be used with advantage in heavy duty flooring compositions.  The procedures for preparing and priming the existing floor and for mixing and application is as described for general purpose floor screeds.

 

Hydro-Guard modified heavy-duty floorings are normally laid as 12 mm toppings.  An exception to this is the iron aggregate flooring, which we recommended laying as a 6 mm topping.

 

A typical heavy-duty composition is as follows :-

 

Portland cement                                                100 kgs

SABS 1090 - 1976 “mortar sand”                    125 kgs

3mm granite chippings                           125 kgs

Hydro-Guard                                       18 litres

Water                                                               as required to adjust consistency

 APPENDIX 1

 

PRACTICAL EXAMPLE OF FORMULATIONS USING DIFFERENT SANDS

(see 2 for grading analysis)

 

a.         Using Witbank plastering sand

 

CEMENT	SAND	DRY HYDRO-GUARD	TOTAL WATER	CONSISTENCY USING FLOWTABLE ASTM C2 30 (MM)
1	3	0,085	0,48	162
1	4	0,085	0,65	171
1	6	0,085	0,87	163
1	3	0,190	0,41	168
1	4	0,190	0,49	161
1	6	0,190	0,73	162

 

b.         Using Pro sand

 

CEMENT	SAND	DRY HYDRO-GUARD	TOTAL WATER	CONSISTENCY USING FLOWTABLE ASTM C2 30 (MM)
1	3	0,085	0,35	162
1	4	0,085	0,39	163
1	6	0,085	0,62	168
1	3	0,190	0,30	182
1	4	0,190	0,31	163
1	6	0,190	0,41	148

 

c.         Using a blend of Pro sand 60% with TMS pit 40%

 

CEMENT	SAND	DRY HYDRO-GUARD	TOTAL WATER	CONSISTENCY USING FLOWTABLE ASTM C2 30 (MM)
1	3	0,085	0,44	193
1	4	0,085	0,52	182
1	6	0,085	0,62	188
1	3	0,190	0,36	195
1	4	0,190	0,41	171
1	6	0,190	0,62	184

 

Summary of results

The control samples had adhesion values between 0 and 350 kp depending upon test conditions. Incorporation of Hydro-Guard markedly improved adhesion to concrete, even at low levels of addition; the advantage of using this Hydro-Guard under both dry and wet conditions are clearly illustrated.

 

These results give definite indication of the benefit of using Hydro-Guard as an admixture to cement for flooring screeds, wall renderings and adhesive layers.

 

 

APPENDIX 2

 

 

SAMPLE DESCRIPTION	PROSAND	TMS PIT	PLASTERING SAND
Relative density	2,66	2,60	2,65
Bulk density :        loose (air dry)                                                     kg/m3                                       consolidated                             (air dry) kg/m3	1570     1710	1360     1570	1240     1470
SCREEN ANALYSIS		per cent passing (by mass)
SABS screens
4 750 um	100	100
2 360   “	99	99
1 180   “	91	95	100
600    “	59	83	98
300    “	21	58	68
150    “	1	22	21
75     “	0,1	8,5	4,5
AVERAGE PARTICLE SIZE FM	2,30	1,43	1,14

 Test data sheet no 1

Tensile strength and flexural strength of cement mortar compositions - effect of Hydro-Guard admixtures.

 

Test data sheet no 2

Adhesion to concrete and adhesion to steel of cement mortar compositions - effect of Hydro-Guard admixtures.

 

Test data sheet no 3

Adhesion to concrete - the effect of adding various levels of Hydro-Guard to cement mortars.

 

Test data sheet no 4

Shrinkage of cement mortars during the drying process - effect of Hydro-Guard admixtures.

 

Test data sheet no 5

Effect of heat ageing upon physical properties of cement mortars.

 

Test data sheet no 6

Resistance to water penetration of cement mortars containing Hydro-Guard.

 

Test data sheet no 7

Freeze-thaw resistance of cement mortar blocks - effect of Hydro-Guard.

 

Test data sheet no 8

Effect of chemical re-agents on the flexural strength of cement mortars.

 

Test data sheet no 9

Co-efficient of linear expansion of cement mortar blocks - effect of Hydro-Guard.

 

Test data sheet no 10

Effect of temperature on the workability time of cement mortars containing Hydro-Guard.

 

Test data sheet no 11

Hydro-Guard cement admixture in modified concretes where resistance to salt (sodium chloride) solutions is required. 

HYDRO-GUARD TEST DATA SHEET NUMBER 1

 

TENSILE STRENGTH & FLEXURAL STRENGTH OF CEMENT MORTAR COMPOSITIONS - EFFECT OF HYDRO-GUARD ADMIXTURES

 

Test method

 

Mortar compositions based on 3 parts BS 12 sand to 1 part Portland cement were prepared.  The following samples were compared in wet and dry tests on tensile and flexural strengths :-

 

Control	no admixture
Hydro-Guard	as admixture at 40 parts per 100 parts cement by weight
vinyl acetate copolymer	as admixture at 40 parts per 100 parts cement by weight

 

Treatment of the test pieces prior to testing were as follows :-

 

Dry testing

1 day drying + 6 days immersion in water + 21 days drying.

 

Wet testing

1 day drying + 6 days immersion in water + 14 days drying + 7 days immersion in water.

 

 

RESULTS

 

 

TEST METHOD	UNMODIFIED MORTAR (CONTROL)	MORTAR MODIFIED WITH HYDRO-GUARD	MORTAR MODIFIED WITH VINYL ACETATE COPOLYMER
Test conditions	KPa	kPa	kPa
dry tensile strength            wet	3050 1800	4350 7950	3300   175
dry flexural strength           wet	7100 5800	10600   9600	11300   1050

 

Summary of results

 

Hydro-Guard gives marked improvement in both tensile and flexural strengths in comparison with the control.

 

Hydro-Guard has special advantages under wet conditions.  In this respect, it is much better than the vinyl acetate copolymer.

 

 

 

 

 

 

HYDRO-GUARD TEST DATA SHEET NUMBER 2

 

ADHESION TO CONCRETE & ADHESION TO STEEL OF CEMENT MORTAR COMPOSITIONS - EFFECT OF HYDRO-GUARD ADMIXTURES

 

Test method

 

Mortar compositions based on 3 parts BS 12 sand to 1 part Portland cement were prepared.  The following samples were compared in wet and dry tests to adhesion to concrete and to steel :-

 

Control	no admixture
Hydro-Guard	as admixture at 40 parts per 100 parts cement by weight
vinyl acetate copolymer	as admixture at 40 parts per 100 parts cement by weight

 

The tests were carried out on “air-cured” samples because wet-curing can lead to unreliable results in tests of this nature.   Treatment prior to testing was as follows :-

 

Dry testing

 

28 days air-drying.

 

Wet testing

 

21 days air-drying + 7 days immersion in water.

 

TEST METHOD	UNMODIFIED MORTAR (CONTROL)	MORTAR MODIFIED WITH HYDRO-GUARD	MORTAR MODIFIED WITH VINYL ACETATE COPOLYMER
Test conditions	KPa	kPa	kPa
Adhesion                     dry to concrete                  wet	70 310	3450 1380	2140   480
Adhesion                     dry to steel                        wet	0     0	1590 1310	1170       0

 

Summary of results

 

Hydro-Guard gives excellent adhesion to concrete and to steel under both dry and wet conditions.  It offers particular advantages over the vinyl acetate copolymer under wet conditions. 

 

HYDRO-GUARDTEST DATA SHEET NUMBER 3

 

ADHESION TO CONCRETE - EFFECT OF ADDING VARIOUS LEVELS OF HYDRO-GUARD TO CEMENT MORTARS

 

Test method

 

Cement mortars, based on 3 parts BS 12 sand to 1 part of Portland cement, were prepared for the test.  Mortars, containing various amounts of Hydro-Guard were compared with control samples without admixture.  After thoroughly drying the test pieces, adhesion to concrete was determined :-

 

            a.         On dry samples

            b.         On wet samples, after 7 days immersion in water

                        and

            c.         On wet samples, after 3 months immersion in water.

 

Results are shown in the graphs.

 

 

ADHESION TO CONCRETE

 

 

kPa	KPa
3500	3500
2800	2800
	3 months immersion
2100                                 28 days	2100
1400	1400
	7 days immersion
700	700
0      10      20      30      40      50    60	0      10      20      30      40     50    60

 

 

Level of HYDRO-GUARD(% on cement weight) 

HYDRO-GUARDTEST DATA SHEET NUMBER 4

 

SHRINKAGE OF CEMENT MORTARS DURING THE DRYING PROCESS - EFFECT OF HYDRO-GUARD ADMIXTURES 

Test method 

To test for shrinkage on setting, a mild steel mould 25 cm long x 2,5 cm wide x 2,5 cm deep was used, and the inner surfaces of the mould were lightly smeared with petroleum jelly before filling with mortar.  The mortars under test were tamped down, levelled and left to dry for 28 days at room temperature.  The longitudinal shrinkage of the mortars was measured at the end of this period using a travelling microscope.

 All mortars testes were based on 3 parts BS 12 sand and 1 part Portland cement.  Control samples without admixture were compared with mortars containing various levels of Hydro-Guard 

Results

 

 

CONTROL	AMOUNT OF HYDRO-GUARDADDED (PARTS PER 100 PARTS OF CEMENT)	WATER / CEMENT RATIO	SHRINKAGE (%)
	NONE	0.40	0.07
HYDRO-GUARD   Hydro-Guard	20 30 40	0.34 0.34 0.30	0.02 0.01 0.01

 

Summary of results

 

In formulating Hydro-Guard for admixture to cement, one of the properties, which have been optimised, is resistance to shrinkage during setting of the modified cement.  The above test results show that Hydro-Guard gives a great improvement in resistance to shrinkage - this is in accordance with qualitative observations on large areas. 

HYDRO-GUARDTEST DATA SHEET NUMBER 5

 

EFFECT OF HEAT AGEING UPON PHYSICAL PROPERTIES OF CEMENT MORTARS

 

Introduction

 

Heat ageing tests are employed to obtain data, which have a bearing on long-term performance.  A general guide used in the rubber industry is that one week at 70ºC approximates to 5 years of normal service life.

 

Test method

Cement mortars were prepared based on 3 parts BS 12 sand and 1 part of Portland cement.

 

Control	no admixture
Hydro-Guard	as admixture at 40 parts per 100 parts cement by weight
all acrylic	as admixture at 40 parts per 100 parts cement by weight

 

Flexural strength was evaluated on “wet-cured” test pieces which had been treated as follows :-

 

1 day drying + 6 days immersion in water + 21 days drying, prior to ageing.

 

Adhesion to concrete was measured on “dry-cured” samples because wet curing can lead to unreliable results in this test.  The test samples were simply dried for 28 days before ageing and testing.

 

RESULTS

Heat ageing at 70ºC

 

	FLEXURAL STRENGTH (kPa)
	INITIAL	1 MONTH	3 MONTHS	12 MONTHS
CONTROL	7100	4800	5500	5200
Hydro-Guard	10600	15700	14800	14400
All acrylic	11900	43000	18500	10100

 

	ADHESION TO CONCRETE (kPa)
	INITIAL	1 MONTH	3 MONTHS	12 MONTHS
CONTROL	70	nil	Nil	nil
Hydro-Guard	3450	2690	1790	2550
All acrylic	2920	2830	2480	2280

 

 

 

 

Summary of results

The tests show that Hydro-Guard retains its effectiveness in cement mortar compositions over long periods of heat ageing, showing marked improvements over unmodified samples.  It compares favourably with the all-acrylic polymer.

 

Hydro-Guardmay therefore be expected to remain effective throughout the normal service life of cement compositions treated with it.

HYDRO-GUARDTEST DATA SHEET NUMBER 6

 

RESISTANCE TO WATER PENETRATION OF CEMENT COMPOSITIONS CONTAINING HYDRO-GUARD

 

Scope

 

Two distinct water-resistant treatments using Hydro-Guard were evaluated viz :-

 

1.         A Hydro-Guard/cement slurry sealing coat system sandwiched between two layers of conventional cement mortar.

 

2.         Cement mortar, based on 3 parts of sharp sand to 1 part of Portland cement, using various levels of Hydro-Guard as admixture.

 

Test method

Preparation of samples

 

Annular, mild steel bands (85mm internal diameter and 15mm depth) were used as moulds for the mortar test samples.  Methods of preparation of the two sets of samples are described below :-

 

1.         Hydro-Guard/cement sealing coats as a water-resistant treatment

            Moulds were filled to half depth with a conventional cement mortar (3 parts of sharp sand to 1 part of Portland cement) and left to dry for 3 days at 20ºC.

 

            After 3 days, a sealing coat consisting of 2 parts of Portland cement slurried with 1 part of Hydro-Guard was brushed on to the upper surface of the dry mortar, ensuring that all brush stroked were made in the same direction.  After 1 hour, a second sealing coat was applied with brush strokes at right angles across the strokes of the first coat.

 

            The coated test pieces were allowed to dry for various periods of time : 24, 48 and 72 hours.

 

            A third coat of fresh slurry was then applied as an adhesive tack coat.  Whilst the third coat was still wet and tacky, a conventional mortar (3 parts of sharp sand to 1 part of Portland cement) was placed on the tack coat, filling the remaining half of the mould.  The “sandwich” test pieces thus obtained were allowed to dry for 7 days at 20ºC prior to testing.

 

 

2.         Hydro-Guard as a water-resistant admixture in the mortar

 

            Cement mortars, based on 3 parts of sharp sand to 1 part of Portland cement, containing respectively 0, 20, 30 and 40 parts of Hydro-Guard per 100 parts of cement were prepared.  Annular moulds, as described above, were completely filled with each composition.

 

The mortars were allowed to dry for 7 days at 20ºC    prior to testing.

 

Testing

 

Each mortar disc, retained in it’s mild steel band, was clamped into a test apparatus designed to apply water pressure, equivalent to a 30 metre head of water, to one face of the disc.  The other face (ie the underside) of the disc was open to the atmosphere.

 

Throughout the test, a constant water pressure was maintained, and the water pressure gauge monitored for any reduction in pressure.   Pressure drop, which in this test indicated sample failure, was corrected where necessary.  Any water which did pass through was collected in a measuring cylinder and the volume recorded.

 

Testing was continued until either a measurable volume of water passed through the sample, or where no water penetrated, for a period of 3 weeks.  On completion of the test, the underside of each sample which withstood 3 weeks testing was carefully examined to ensure that there was no sign of water penetration.

 

Details of the test apparatus will be supplied on request.

 

Results

 

Results, expressed in mls of water passing through the samples, are shown in the following tables :-

 

1.         Hydro-Guard/cement sealing coats as a water-resistant treatment

 

           

DRYING TIME OF SEALING COAT	VOLUME OF WATER PASSING THROUGH SAMPLE (MLS)
SYSTEM (HRS)	3 HRS	3 DAYS	3 WEEKS
24	5	28	-
48	NIL	NIL	NIL
72	NIL	NIL	NIL

 

Note

The conventional cement mortar compositions used to “sandwich” the Hydro-Guard/cement sealing coats tested above were based on BS 882 Zone 2 sand.

 

Another conventional mortar composition, based on BS 12 sand, was also used in these experiments.  Here, the sealing coat system was tested after 72 hours drying only.  Again, no water penetrated after 3 weeks.

 

2.         Hydro-Guardas a water-resistant admixture in the mortar

 

 

LEVEL OF HYDRO-GUARD ADDED (PARTS PER 100 PARTS OF CEMENT BY WEIGHT)	VOLUME OF WATER PASSING THROUGH SAMPLE (MLS)
	3 HRS	3 DAYS	3 WEEKS
0	71	-	-
20	23	-	-
30	NIL	NIL	NIL
40	NIL	NIL	NIL

 

Note

 

These mortar compositions were prepared using BS 882 zone 2 sand.  Another composition, based on BS 12 sand and containing 40 parts of Hydro-Guard per 100 parts of cement was also tested.  No water penetrated after 3 weeks.

 

Summary of results

 

The results of these tests show that the following treatments provide effective water resistance for cement mortars :-

 

1.         Two sealing coats plus one tack coat using Hydro-Guard/cement slurry

            Portland cement (2 parts) is slurried with Hydro-Guard(1 part) and two coats of the slurry are applied at right angles across each other on the surface to be treated.

 

            Following this, at least 48 hours drying is allowed, and then a fresh slurry of cement and Hydro-Guard is applied at a tack coat for the surfacing mortar.

 

2.         Mortar modified with Hydro-Guard

 

            40 parts of Hydro-Guard per 100 parts of cement gives a water-resistant mortar (3 parts sand to 1 part of cement) using a suitable sand.

 

            For optimum results, the system of two sealing coats plus one tack coat of Hydro-Guard/cement slurry (1) may be combined with the Hydro-Guard modified mortar (2); see alto Technical Bulletin No GEN TB25 page 3.

 

            Because water-resistant treatments are specialised procedures, we advise each customer to consult us for recommendations appropriate to his individual requirements.

 

 

 

HYDRO-GUARD TEST DATA SHEET NUMBER 7

 

FREEZE-THAW RESISTANCE OF CEMENT MORTAR BLOCKS - EFFECTS OF HYDRO-GUARD

 

Test method

 

Test pieces were prepared from mortars based on 3 parts BS 12 sand and 1 part of Portland cement.  Hydro-Guard was used at the level of 40 parts Hydro-Guard to 100 parts cement ( by weight) and compared with controls without admixture.  All test pieces were dried for 24 hours, immersed in water for 7 days, then dried for 21 days before testing.

 

The samples were frozen in a 10% aqueous solution of sodium chloride - this was chosen in preference to water to accelerate deterioration.   Each freeze-thaw cycle was as follows :-

 

Frozen for 20 hours in a 10% sodium chloride solution at -18ºC.

 

Thawed and examined.

 

Test pieces were subjected to a number of freeze-thaw cycles, allowed to dry out, then tested for flexural strength.

 

Results

The results are compared with figures obtained on samples not subjected to freeze-thaw treatment :-

 

	LEVEL OF HYDRO-GUARDADDITION	FLEXURAL STRENGTH (kPa)
	(PARTS) PER 100 PARTS CEMENT	BEFORE FREEZE-THAW TREATMENT	AFTER 15 FREEZE-THAW CYCLES	AFTER 60 FREEZE-THAW CYCLES
CONTROL NO HYDRO-GUARD	NONE	7100	4500	-
HYDRO-GUARD	275	10600	-	10400

 

 

Summary of results

 

The control samples could not be tested for flexural strength after more than 15 freeze-thaw cycles because of severe deterioration.  On the other hand, the Hydro-Guard modified test pieces showed no visible signs of deterioration after 60 cycles, thereby confirming the efficiency of Hydro-Guard in combating freeze-thaw damage to concrete.

 

 

 

HYDRO-GUARD TEST DATA SHEET NUMBER 8

 

EFFECT OF CHEMICAL RE-AGENTS ON THE FLEXURAL STRENGTH OF CEMENT MORTAR

 

Test method

Mortar blocks, based on 3 parts of BS 882 Zone 2 sand to 1 part of Portland cement were prepared.

 

Control	no admixture
Hydro-Guard modified mortars	incorporating 25 parts of Hydro-Guard per 100 parts of cement by weight

 

Prior to testing all mortar blocks were cured as follows :-

            1 day drying + 6 days immersion in water + 21 days drying.

 

Flexural strength was determined

1.         Immediately after curing and

2.         After prolonged submersion in various chemical re-agents, followed by rinsing in clean water and drying for 7 days at room temperature.

 

Results

1.         Flexural strength values obtained immediately after curing were as follows :-

            control mortar                           7250 kPa

            Hydro-Guard modified mortars 13200 kPa

2.         The flexural strength values obtained after prolonged submersion of samples in various chemical reagents are shown in the following table :-

 

		FLEXURAL STRENGTH (kPa)
		AFTER 3 MONTHS SUBMERSION		AFTER 6 MONTHS SUBMERSION
		CONTROL MORTAR	HYDRO-GUARD MODIFIED	CONTROL MORTAR	HYDRO-GUARD MODIFIED
	REAGENT
SECTION A	10% POTASSIUM HYDROXIDE SOLUTION	9000	9450	6150	12350
	10% MAGNESIUM SULPHATE SOLUTION	8400	10300	4350	13300
	5% LACTIC ACID SOLUTION	6150	9750	5950	8000
	10% SUCROSE SOLUTION	7050	11500	5950	9200
SECTION B	5% HYDROCHLORIC ACID SOLUTION	2400	4900	0	2200
	20% AMMONIUM NITRATE SOLUTION	5250	8300	2550	4850

 

SECTION C

PETROLEUM SPIRIT

7400

8400

7750

7500

 

 

Summary of results

 

REAGENTS	REMARKS
SECTION A
* Potassium hydroxide  * Magnesium sulphate     Lactic acid     Sucrose	Definite advantages may be gained by using Hydro-Guard- modified mortars.  Note the high flexural strength figures after 6 months for chemical marked *.
SECTION B
Hydrochloric acid Ammonium nitrate	Hydro-Guard is of some benefit. Nevertheless, after 6 months, flexural strength is seriously impaired.
SECTION C
Petroleum spirit	Hydro-Guard modified mortars offer no advantages in the presence of petrol or related fuels/oils

 

 

These results represent only a small, selected cross-section of chemical resistance test data obtained in our laboratories.  It is stressed that the results, which were obtained on small mortar blocks prepared and tested under laboratory conditions, are offered only as a guide to performance.

 

We can supply information regarding the behaviour of Hydro-Guard-modified mortar in the presence of chemicals other than those listed above. And we will be pleased to discuss the requirements of the individual customer.

 

 

 

 

 

HYDRO-GUARD TEST DATA SHEET NUMBER 9

 

CO-EFFICIENT OF LINEAR EXPANSION OF CEMENT MORTAR BLOCKS - EFFECT OF HYDRO-GUARD

 

Test method

 

Cement mortars, based on 3 parts of sharp sand to 1 part of Portland cement, were prepared for the test.  Control samples were compared with samples containing Hydro-Guard added at the level of 30 parts Hydro-Guard per 100 parts of cement).

 

Mild steel moulds, 10,7cm long x 5cm deep were constructed for the test and the linear surfaces lightly smeared with petroleum jelly before filling with mortar.  The mortars under test were tamped down, levelled and removed from the moulds after 24 hours drying.  The test pieces were then cured by immersion in water for 3 days followed by drying for 24 days before testing in the laboratories of an independent group of testing engineers and consultants.

 

The co-efficient of linear expansion was determined in the following temperature ranges :-

 

                1.            - 20°C to + 20°C

            2.         +20°C to + 60°C

 

Results

 

The results obtained are shown in the following table :-

 

		CO-EFFICIENT OF LINEAR EXPANSION
	WATER / CEMENT RATIO	TEMPERATURE RANGE -20°C TO 20°C	TEMPERATURE RANGE 20° TO 60°C
CONTROL SAMPLES	0.40	12.7 X 10 –6	12.8 X 10 -6
HYDRO-GUARD MODIFIED SAMPLES	0.30	12.8 X 10 –6	12.9 X 10 -6

 

Summary of results

 

The use of Hydro-Guard as a Hydro-Guard ad mixture has no effect on the co-efficient of linear expansion of this typical cement mortar composition.

 

 

HYDRO-GUARD TEST DATA SHEET NUMBER 10

 

EFFECT OF TEMPERATURE ON THE WORKABILITY TIME OF CEMENT MORTARS CONTAINING HYDRO-GUARD

 

Test method

 

Mortar compositions based on 3 parts of BS 882 Zone 2 sand to 1 part of cement were prepared for the test.  Hydro-Guard was included as admixture at the level of 40 parts Hydro-Guard per 100 parts cement by weight, and the water/cement ratio adjusted to 0.31-.  Mortars were prepared using two different types of cement.

 

·                    Ordinary Portland cement

·                    rapid hardening cement

 

The workability time of each type of cement mortar was assessed at various ambient temperatures within the range 1 to 32°C.

 

Results are shown in the graph overleaf.

 

Summary of results

 

Hydro-Guard-modified cement mortars were found to have practicable workability times at temperatures ranging from about 30°C down to 20°C.  Ordinary Portland cement gave satisfactory results at temperatures down to 7°C, whereas rapid hardening cement was more suitable for the low temperature range, ie 2 - 7°C.

 

The British Standard Code of Practice CP114: Part 2 : 1969 recommends that concreting should not be carried out unless “the concrete has a temperature of at least 4°C and that the temperature of the concrete is maintained above 2°C until it has thoroughly hardened”.  Similarly we would not recommend the application of Hydro-Guard-modified mortars and concretes unless the above recommendations can be met.  When applying the modified mortar or concrete at temperatures between 2 and 10°C, a rapid hardening cement should be used.

 

 

 

HYDRO-GUARDTEST DATA SHEET NUMBER 11

 

HYDRO-GUARD CEMENT ADMIXTURE IN MODIFIED CONCRETES WHERE RESISTANCE TO SALT (SODIUM CHLORIDE) SOLUTIONS IS REQUIRED

 

 

Test results

 

	WATER/ CEMENT	CHLORIDE CONTENT 1/16” TO 1/2” DEPTH		CHLORIDE CONTENT 1/2” TO 1” DEPTH
	RATIO	AVERAGE	RANGE	AVERAGE	RANGE
HYDRO-GUARDMIX	0,4	5,9	2,92 - 9,44	0,59	0,07 - 1,58
CONTROL	0,4	12,4	10,8 - 15,7	2,25	1,43 - 3,27
CONTROL	0,5	13,7	12,2 - 15,8	3,85	2,80 - 4,44

 

Test details

Four test samples 12 x 12 x 1¼“ of each mix were prepared by normal techniques, using reasonable vibration by rodding and mould wall tapping.  The samples were covered with dry burlap (hessian-like material) and polythene sheet for 24 hours.  Samples were then de-moulded and cured for a further 19 days at 70+ 2°F at 50 ± 5% relative humidity.

 

The top surface of the cured samples was dry abraded by grinding or sandblasting to reduce the height by 1/16 - 3/16”.  Dams, 3/4” high by 1/2” wide were placed around the top edges of three of each set of four samples.  The three samples were covered with 1/2” of 3% aqueous sodium chloride solution.  During ‘ponding’ the samples were kept at 70 ± 2°F and 50 ± relative humidity.

 

At the end of 90 days, the solution was removed.  After drying the surfaces of the samples were wire brushed until all salt build-up had been removed.

 

Three samples of concrete were taken from each specimen (including the ‘unponded’ ones) by dry coring (1½“ minimum diameter) and the cores cut to obtain specimens.

 

A.        1/16” - ½“ depth from the surface and

B.         ½“ - 1” depth from the surface.

 

These sections were crushed and analysed for chloride content.  The average value obtained from the ‘unponded’ samples was subtracted from the average value obtained from the ‘ponded’ samples, and the result expresses as pounds of chloride (CI) per cubic yard of concrete.  (Although not yet officially specified, a maximum acceptable value of chloride in the  ½“ to 1” depth is less than 1.2 lb of chloride per cubic yard.  Usual values in the 1/16” to  ½“ depth sections are 5 to 9 lbs of chloride per cubic yard).

 

 

 

 

 

 

 

Mix design

 

The mix design used in the tests was as follows :-

 

                                                            lbs

Portland cement - type 1                       94

Concrete sand                                      275

Coarse aggregate, 8                              180

Hydro-Guard                           29,4

 

Water : added as required to give water/cement ratio of 0,40 with a slump of 4-6” and air content of less than 6%.

 

Control mixes (no Hydro-Guard) were made with water/cement ratios of 0.40 and 0.50.

 

Concrete sand gradation was :-

 

100%                           smaller than 12,5 mm

85 - 100%                              “         9,5 mm

10 - 30%                                “        4,75 mm

0 - 10%                                   “        2,36 mm

 

Coarse aggregate (8) gradation was :-

 

100%                           smaller than   9,5 mm

95 - 100%                                 “       4,75 mm

80 - 100%                                 “        2,36 mm

50 - 85%                                   “        1,18 mm

25 - 60%                                   “        0,06 mm

10 - 30%                                   “        0,03 mm

2 - 10%                                     “        0,015 mm

 

Conclusion

 

Hydro-Guard gave very good results in these tests showing a great improvement compared with the controls.  It has been approved by the US Federal Highway Administration for use in Highway Systems, particularly in bridge deckings.

 

Hydro-Guard may also be recommended for use in other concretes and mortars where protection from salt erosion or damage is required.