1.0.1 This code is formulated with view to standardizing the applications of concrete admixtures, improving the concrete performance, satisfying the requirements of design and construction, guaranteeing the quality of concrete works, and accomplishing advanced technology, safety and reliability, economy and rationality, energy conservation and environmental protection.
1.0.2 This code is applicable to the application of normal water reducing admixture, superplasticizer, polycarboxylate superplasticizer, air entraining admixture, air entraining and water reducing admixture, accelerating admixture, set retarding admixture, pumping aid, anti-freezing admixture, quick setting admixture, expansive admixture, water-repellent admixture and corrosion-inhibition admixture in concrete works.
1.0.3 In addition to the requirements stipulated in this code, the application of concrete admixtures in concrete works also shall comply with those specified in the current relevant standards of the nation.
2 Terms and Symbols
2.1 Terms
2.1.1 Shrinkage-reducing type polycarboxylate superplasticizer
The polycarboxylate superplasticizer of which the 28d shrinkage ratio is not larger than 90%.
2.1.2 Compatibility between water reducing admixtures and other concrete raw materials
The liquidity of the mixture and its time-dependent change degree when the concrete admixture containing water reducing components is mixed with cementing material, aggregates and other admixtures.
2.2 Symbols
E- the elasticity modulus restricting the steel bars, MPa;
h0- the initial reading of specimen height, mm;
ht- the height reading of specimen at age of t, mm;
h- the reference height of specimen, mm;
L- the measured value of initial length, mm;
L0- the reference length of specimen, mm;
Lt- the measured value of the length of specimen at the tested age, mm;
σ- the expansion or shrinkage stress, MPa;
ε- the restrained expansion rate at the tested age, %;
εt- the vertical expansion rate, %;
μ- the reinforcement ratio, %.
3 Basic Requirement
3.1 Selection of Chemical Admixtures
3.1.1 The variety of admixture shall be selected according to the design and construction requirements as well as the main functions of admixture.
3.1.2 Where the admixtures from different suppliers and of different varieties are used simultaneously, they shall pass experimental verification and shall be used after ensuring that the concrete performance meets the design and construction requirements.
3.1.3 Concrete admixtures containing such components as hexavalent chromium salt, nitrite and thiocyanate must not be used for the concrete of drinking water engineering directly contacting the drinking water after completion.
