The zeolite in the production of concrete
A high pozzolanic activity of the zeolite has made it possible to use it as an active
mineral additive in production of durable, frost - , moisture-, acid-, sulfate resistant
high strength concretes. Such concretes are used in hydraulic structure constriction
as well as bridges, overpasses, port installations.
With the introduction of activated zeolite into the concrete in an amount of 10-20% of the cement mass (М400, М500) plasticizers need no application, as the zeolite gives high plasticity and concrete workability. If a plasticizer is used, its consumption should be 0,3 – 0,4 % of cement dry weight.
10 % of activated zeolite introduction in to solution reduces thermal conductivity of mortar mix in 5-10 times. The solution becomes elastic, has a high water holding capacity, and doesn’t break down. The zeolite use in solutions makes it hot which makes it possible to remove a cold bridge when bonding.
The activated zeolite introduction in concrete improves quality class up to 750-800 andwaterproofness up to W14-20.
The activated zeolite use in concrete and concrete goods makes it possible to reduce time and temperature of steam operation. The zeolite is an internal agent in concrete curing, absorbing and keeping water inside for a certain time and then gradually giving it to the cement, promoting its full hydration.
The zeolite in the production of cement
Activated zeolite is activity mineral additive, used in constructional materials production including cement. Natural zeolites are introduced in class-list of active mineral additives in accordance with OST 21-9-90, and its appliance in cement production is regulated by GOST 10178-85. Natural zeolites have a high pozzolanic activity (up to 300 mg СаО per 1 gr) and can be introduced in 10-20 % doses from clinker mass. Moreover the natural zeolite can take a part of clinker grinding intensifier, increasing efficiency of a mill on 5-15 %.
The zeolites particularly well suited for hydraulic cement production, resistant to ambient chemical action, for example sea water.
The unique zeolite properties specified its possibility of use as an active mineral additive in acid proof, sulfate resistant cements production.
Partial clinking substitution on 15-20% of zeolite makes it possible to get 400, 500 mark cement, 300 mark portland – pozzoland cement with decreased start time and final set.
When using zeolites in cement production, setting time decreases, start is 1,5 hours, finishes in 3 hours, specific surface is increased on 800-1900 m2/t., the cement brand is increased
The zeolite in the production of cement
Cement properties with natural zeolites addition
Efficiency of zeolite appliance in hardening systems, received by clinker mixed grinding, gypsum rock and 10-15 % of natural zeolites up to the residual of 15% on the sieve №008 have been studied. It is found that these properties are different from non-additive. Thus, specific surface cement flours increases from 270-310 сm2/g to 420-550 сm2/g by Blaine. Water requirement grows up 24-26% tо 26-30%. Herewith test routine setting time, generally decreases to 15-60 min.
Stone strength on cements with the addition of 10-15% zeolite powder in early periods of hardening (t=20±50С; age 3, 7, 14 days) is lower on 10-15 %, than non-additive . This is typical for all pozzolanic cements. In later terms (28, 90, 180 days), and also after thermal conditioning, stone strength on mixed cements is higher than the stone on ordinary Portland cement. Zeolite desired content in cement is 10-15%. Herewith the strength of zeolite-containing blastfurnance cements is higher non-additive in all periods of hardening. When slag sand partial constitution by the zeolite (10-15%), cement paste rheological characteristics are improved (yield value and dynamic viscosity), 10-15 % water gain is decreased. Increased stone sponginess and contraction value in early periods of hardening (up to 14 days) with hydration time increasing are decreased more intensively for zeolite – containing cementing. Samples of such cement are characterized by better resistance against sulfate ion attack (Кс/с=0,93 — 1,04), in acid solution (Kd .=0,81 in comparison with control 0,68 after 1-hour boiling in 40 % dipping acid), and also better freezing resistance (at cycles F=100 strength reduction is 3% in comparison with 10 % for non-additive concretes).
The zeolite in dry mortars production
The activated zeolite is a good filler at dry mortars production as on cement, and as on gypsum bases. It is a good plasticizer, makes dry mortars placeable, flexible, and increases its pot life, increases strength, water resistance, freeze resistance, decreases thermal conductivity.
Zeolites containing dry mortars have high strength mixture adhesion with various bases (concrete, silicate brick, and ceramic, all kinds of foam mortar, gypsum plasterboard, and stone bed). It is no required previously ground the surface. The zeolite gives the mixtures humidity resistance, mixtures have a high water holding capacity (99,64%) and crack resistance. Biostability and fire resistance are significant for compo mortar. Mixtures have microbicidal properties. The zeolite reduces heat conductivity factor that makes plaster, glue and floor mixes hot. Having a high dispersive ability, the zeolite prevents from dry mortars solidifying and when mixing with water nubbles are not formed. A universal adhesive based on zeolite is used for all kinds of foam mortar, foam concrete, gas silicate, and polystyrene concrete, concrete, for ceramic floor tile and facade tile, for ceramic brick etc. High specification and low cost make the adhesive competitive on the market of dry mortars. Repair mortars with zeolite have a good adhesion, high strength, water resistant, (W10-W20), high freeze resistance F400 and low conductivity (0,2-0,3 W/m*К). Successfully applied on construction sites, equal foreign analogue and even exceed it in some specification.