One, the development history of concrete admixture
1 in the 20th century, the early 90s preferred the United States put forward the concept of high performance concrete (HPC), is a new type of super plasticizer and concrete material science combining successful example.
2, the British I.Aspdin in 1824 to get the Portland cement, cement concrete has been widely used.
3, 1962 Japanese Hattori Kenichi first the naphthalene sulfonate formaldehyde condensate (n = 10) for concrete dispersant, 1964 Japan Kao soda company as sales of the products.
4, in 1963, the Federal Republic of Germany to develop the melamine sulfonate formaldehyde condensate, and the emergence of a polycyclic aromatic hydrocarbon sulfonate formaldehyde condensation.
5. In 1966, the first application of high strength concrete in Japan began to produce pre stress concrete piles.
6, 1971~1973 years, Germany will be preferred superplasticizer developed concrete, concrete vertical pumping height reached 310m.
7, the current direction of development is HPC and using composite super plasticizer (CSP) research and implementation of HPC with than the calculation of the design method and the CSP formulation design.
Two, the development direction of concrete admixture
1, high efficiency and reducing agent, naphthalene and melamine superplasticizer modified, polyacrylate super plasticizer, polyacrylic acid then branched copolymer superplasticizer, sulphamate superplasticizer, sulfonated acetone formaldehyde polycondensate, lignin sulfonate, and industrial waste to produce superplastic agent.
2 composite admixture: low alkali low dosage liquid compound additive composite plasticizer and formulation design, low alkali, low volume liquid composite antifreeze, micro expansion multifunctional waterproof agent, liquid expansion agent, liquid accelerator, Super Retarder
3, other additives: shrinkage reducing agent, alkali aggregate reaction inhibitor, surface hardening agent, release agent,
Three functional classification of concrete admixture
1, definition: "concrete admixture classification, nomenclature and definition" GB8075-87, is in the process of mixing concrete added, to improve the performance of concrete material, the content is not greater than the cement quality of 5% (except for special cases).
2, concrete admixture according to the main function is divided into four categories:
A, improve the rheological properties of concrete admixtures. Including water reducer, air lead agent and pumping agent.
B, adjusting the setting time of concrete, hardening properties of the admixture. Including retarder, early strength agent and quick setting agent.
C, improve the durability of concrete admixture. Including air lead agent, water repellent agent and rust inhibitor, etc..
D, improve the other properties of concrete admixture. Including air entraining agent, bulking agent, antifreezing agent, coloring agent, waterproofing agent and pumping agent.
Four, admixture by varieties classification
1, early strength agent:
A, soluble inorganic salt chlorides, carbonates, nitrates, sodium thiosulfate, silicate, aluminate, alkaline hydroxide
B, soluble organic matter: triethanolamine, calcium formate, calcium acetate, calcium propionate and calcium butyrate, urea, oxalic acid, amines and formaldehyde condensates.
2, accelerator: iron, fluoride, aluminum chloride, sodium aluminate, potassium carbonate.
3, air lead agent: wood resin salt, synthetic detergent, lignin sulfonate, protein salt, fatty acids and resin acids and their salts.
4, water reducing agent and retarder: lignin sulfonate and its change or derivatives, hydroxy carboxylic acid and its salt or the and derivatives, inorganic salts (zinc salt, borate, phosphate, chloride), ammonium salt and its derivatives, carbohydrates and polysaccharide acid or sugar, acid, water soluble polymers (cellulose ethers, melamine derivatives, naphthalene derivatives, polysiloxane and sulfonated hydrocarbons
5, high efficiency water reducing agent: naphthalene sulfonate formaldehyde condensate, polycyclic aromatic hydrocarbon sulfonate formaldehyde condensate, melamine formaldehyde condensation polymerization, the amine groups of formaldehyde, sulfonated ketone aldehyde condensation polymerization, polypropylene acid salt and its graft copolymer, etc..
6, gas filling agent: hydrogen peroxide, metal powder, some active carbon adsorption air.
7, grouting admixture: retarder, gel, gel starch and methyl cellulose, bentonite, thickening agent, early strength agent, filling agent.
8, expansion agent: fine iron powder or granular iron powder and oxidation accelerator, lime, sulfur aluminate series.
9, binder: synthetic latex, natural rubber latex.
10, pumping agent, synthetic or natural water soluble polymer increased viscosity agent, organic flocculant, high surface inorganic materials (bentonite, silica, asbestos powder, short asbestos fiber, etc.), cement mixing material (fly ash and water lime, powder).
11, flocculant: polymer electrolyte.
12, a colorant: grey to black (black iron oxide, black mineral, carbon black, ultramarine blue, phthalocyanine blue), pink to dark red iron oxide), brown (Sienna, raw umber, burnt umber), green (chrome oxide green, butylphthalide's mu), white (titanium dioxide),
13, sterilization agent and insecticide, dieldrin: halide emulsion and copper compounds.
14, moisture agent: soap, Ding Ji stearic acid, some oil products
15, anti - seepage agent: water reducer, calcium chloride.
16, the alkali aggregate reaction inhibitor: lithium salt, barium salt, some air entraining agent, water reducer, retarder, volcano ash.
17, resist rust agent: sodium nitrite, sodium benzoate, lignin sulfonic acid calcium, phosphate, sodium silicate, sodium silicate, sodium fluoride.
