CALUCEM DAYS - EVONIK NUTRITION & CARE GMBH

Transcription

1 CALUCEM DAYS - EVONIK NUTRITION & CARE GMBH WATER RESISTING ADDITIVES FOR CEMENT BASED BUILDING MATERIALS BY USING SILICONE TECHNOLOGIES 3.NOVEMBER 2016 MARKUS ROOS Page 1

2 AGENDA Basics Silicone Chemistry Test Results Page 2

3 DAMAGE MECHANISM: I. WATER UPTAKE DUE TO CAPILLARY ACTION Water transport in pores due to capillary action bigger pore Smaller pore Capillary action occurs if the adhesion of water to the walls is stronger than the cohesive forces between the liquid molecules. Water The smaller the pore diameter the higher is the capillary pressure to raise water. Page 3

4 Damage mechanism II. Efflorescence Efflorescence The optical function of concrete elements can be affected by efflorescence. Primary Efflorescence The calcium hydroxide Ca(OH) 2 of young concrete can react with carbon dioxide CO 2 from the air. The result is a whitish efflorescence of calcium carbonate CaCO 3 on the young concrete surface. Secondary Efflorescence Minerals solved in water are transported to the surface. If the water evaporates the salts will remain on the top. Crystallisation pressure By reversibly absorbing crystallization water the volume of certain salts increases. This crystallization pressures cause structural cracks. Na 2 SO H 2 O + < 32,7 C >>> Na 2 SO4. H 2 O Page 4

5 DAMAGE MECHANISM: III. FREEZE / THAW DAMAGE Water freezes to ice Volume increase by almost 10% Destroyed cement based joints due to freeze deicing damage Page 5

6 DAMAGE MECHANISM: IV. REBAR CORROSION Page 6

7 AGENDA Basics Silicone Chemistry Test Results Page 2

8 SILICONES Benefits physiologically indifferent high chemical stability low surface tension liquid in a broad field of temperature good gliding properties good spreadability hydrophobic high temperature stability M D D M R Page 8

9 Low surface tension to avoid water uptake Surface Tension is responsible for the shape of liquid droplets Water and dissolved pollutions are repelled by a TEGOSIVIN treatment TEGOSIVIN Low Surface Tension High Surface Tension e.g. pure water (72 mn/m) Page 9

10 MAJOR USED SILICONES AS WATER REPELLENTS OR RO RO R Silanes Siloxanes Silicone Resins monomeric molecules low molecular weight alkoxyfunctional high VOC Octyl-/iso-octyl-/isobutyl alkyl chain-length provides steric protection oligomeric or polymeric molecules alkoxyfunctional organo-modified siloxanes low VOC good beading performance highly branched polysiloxanes of higher molecular weight less penetration depth low alkaline stability provide excellent beading properties excellent impregnation depths specifically in alkaline substrates ( concrete ) can be used in low solid formulation mainly used for hydrophobisation of neutral and natural substrates Only used in coatings Page 10

11 SILANE STRUCTURES FUNCTIONALITY Weaker Alkali resistance by steric hinderance Stronger Methyl (CH 3 ) Short Length of Alkyl chain - Hydrophobic Groups Long Octyl (C 8 H 17 ) Stronger Water Repellency Weaker Methyltriethoxysilane [MTEOS] H H C Si H Alkyl Groups Water Repellency CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 Si n-octyltriethoxysilane [n-octeo] R O Reactive Alkoxy Groups - Bonding R O Faster Reaction speed Slower Methoxy (OCH 3 ) Ethoxy (OC 2 H 5 ) Short Length of Alkyl chain Bonding Groups Long Little Mobility Better Page 11

12 SILICONE WATER REPELLENTS PRODUCT CLASSES Concentrates for solvent born systems 100% actives Diluent: white spirit Ready for use concentation 5-100% For the use on very dense substrates Silanes mainly for concrete protection Siloxanes for neutral and natural substrates only Concentrates for water born systems % actives Diluent water Ready for use concentation 5-40% For the use on variety of substrates Silanes mainly for concrete protection Siloxane/Siloxane blends for neutral and natural substrates only For the use as an admixture into concrete Pasty systems ready for use 25-80% actives Ready to use no dilution is needed High active cremes are for special applications like DPC and concrete protection Low actives cremes for fassade application Powdered products % actives Ready for use Just for drymix mortar applications Preblended into mortars Page 12

13 APPLICATION FIELDS Water Repellency and Efflorescence Control Our high performance water repellents provide durable protection against water by Silane and Siloxane technologies. They are highly efficient hydrophobizing agents for concrete and dry-mix applications: Drymix Mortars Semi Dry Concrete Renders Repair Mortars Technical Mortars Flooring Products Tile Adhesives Grouts Joint Fillers Pigmented Concrete Concrete pavers Wet Concrete Prefab concrete Concrete tubes Concrete curbs Transport concrete Water proofing concrete Page 13

14 AGENDA Basics Silicone Chemistry Test Results Page 2

15 ADMIXTURE PREPARATION Powdered Admixture Blend all the dry components for 2 minutes with a Mixer at low shearing speed. Add the water to the dry blend and keep on stirring for 1 Minute. Fill the mortar into forms and compress it with a vibrator table for 45 sec. Seal the form with a cover and store it for 2 days at room temperature. Remove the concrete from the form and store it for additional 26 days at room temperature before you make the water absorption tests. Liquid Admixture Blend the admixture with the water at first. Add the water/admix blend to the dry blend and keep on stirring for 1 Minute. Fill the mortar into forms and compress it with a vibrator table for 45 sec. Seal the form with a cover and store it for 2 days at room temperature. Remove the concrete from the form and store it for additional 26 days at room temperature before you make the water absorption tests. Page 15

16 CAPILLARY WATER UPTAKE ACC. TO EN ISO After impregnation and airing, the test specimens are, as described above, stored on a soft foam saturated with polyurethane ether. Due to their own weight, the specimens press water out of the foam, so that constant contact of the contact surface is ensured. By weighing after 1h, 4h, 9h, and 25h, the water uptake in g/m² is monitored. Before each weighing, any water adhering to the surface is blotted with an absorbent paper towel. The reduction of water uptake should be > 70 % relative to the blank value. Page 16

17 SILANE/SILOXANE BASED WATER REPELLENTS FOR DURABLE PROTECTION 350 Capillary water uptake of treated tile grouts over repeated test cycles mg/cm² Stearates: Loss of Protection Siloxane/Silane: permanent 0 10 min. 20 min. 30 min. 60 min. 4 h 6 h 24 h 48 h 72 h Time Control 1st cycle Metalsoaps 4th cycle, Metalsoaps 1st cycle, Sitren P 750 4th cycle, Sitren P 750 Page 17

18 SITREN P 750 IS HIGHLY EFFICIENT AT REDUCING WATER ABSORPTION THROUGH CAPILLARY UPTAKE 6 WATER ABSORPTION (%) Blank 0.1% - P % - P % - P % - P % - P H 5 H 8 H 24 H 48 H *: REFERRED TO TOTAL AMOUNT OF DRY COMPONENTS TIME (HOURS) Page 18

19 SALT BLOOMING RESULTS - SECONDARY EFFLORESCENCE Determination of the salt blooming according DIN The hardened concrete (28d) is placed partially (approx. 1 cm) in a sodium sulfate solution (100g sodium sulfate / 900g water). The surface control for salt blooming has daily observed for results up to 14d. Mixing Design Cement I 42,5 R 900 g Sand < 2 mm 2700 g Water repellent 0,9 g Pigment 7,2 g Water 360 g Control Metal Soap Siloxane / Silane Page 19

20 SILICONE BASED POWDERED WATER REPELLENT COMPRESSIVE STRENGTH AT 1, 7, & 28 DAYS 30 COMPRESSION (MPA) BLANK 0.1% - P % - P % - P % - P % - P TIME (DAYS) *: REFERRED TO TOTAL AMOUNT OF DRY COMPONENTS Specimens are made and cured according to ASTM C 109. From each formulation at least 3 specimen are prepared. Release agent is not used on the mold to avoid any possible interference. Page 20

21 NO INFLUENCE ON FRESH MORTAR PROPERTIES AIR CONTENT & FLOWABILITY % Air Content (%) Mortar 0.1% 0.2% 0.3% 0.4% 0.5% % SITREN P 750* mm Flow (mm) Mortar 0.1% 0.2% 0.3% 0.4% 0.5% *: REFERRED TO TOTAL AMOUNT OF DRY COMPONENTS % SITREN P 750* Page 21

22 PROTECTION AGAINST ALGAES Concrete slabs with silicone based water repellent (speciman middle) 1 year of outside exposure Only the speciman containing silicones shows no dirt pick up and no growth of algae Page 22

23 SILICONE BASED WATER REPELLENTS SET THE JS BENCHMARK Outperforming Most Competitive Products In contrast to common metal soaps, Silicone based products provide long lasting performance and cannot be washed out. Stearates lose their effectiveness relatively fast. Benefits are: Efflorescence control Outstanding water repellency Reduced water absorption Durability Very good free-flow behavior Paintable High alkaline stability Easy handling Improvement of tensile adhesion strength Page 23

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