The compressive strength is higher than that of the mixed concrete and the reference concrete at the same age. Compared with the water-cement ratio, Sodium Gluconate has some reinforcing effect on the hardened concrete. The biodegradation of Sodium Gluconate is very small, but its auxiliary plasticizing effect is stronger when it is compounded with naphthalene superplasticizer.
Under the condition of water-cement ratio, when the content of sodium naphthalate is the same, the Sodium Gluconate mainly affects the strength of concrete for 3 days and 7d, and the effect is small. As for the impact of the early development of concrete strength. However, when the Sodium Gluconate content exceeds 0.01%, Sodium Gluconate has a great influence on the early strength of concrete, and even affects the late strength of concrete, especially the late strength will be greatly reduced.
Under the condition of water-cement ratio, the addition of Sodium Gluconate to concrete is different when the amount of naphthalene superplasticizer is different. Qinling 32.5r, the naphthalene superplasticizer dosage of 0.8%, the content of 0.06% of Sodium Gluconate and its compound when the highest strength of concrete; and for shield 32.5r, is 0.08% of the content of gluconic acid Sodium and naphthalene complex when the highest strength of concrete. When the content of naphthalene superplasticizer is 1.0%, the content of Sodium Gluconate with the content of 0.08% is the highest, and the amount of Sodium Gluconate and naphthalene is 0.06% The strength of the concrete when the compound is the highest.
Thus, the difference in cement species also leads to the upper limit of Sodium Gluconate. However, for different varieties of cement, Sodium Gluconate in the appropriate dosage range with the superplasticizer complex will increase the late strength of the coagulation.
Sodium Gluconate can not only extend the cement concrete coagulation time, so that mixed concrete for a long time to maintain plasticity, in order to pour, improve construction efficiency, Sodium Gluconate but also delay the hydration of cement hydration, reduce the occurrence of cracks. Therefore, it is used extensively in mass concrete, pumping concrete, hot weather construction and some special construction processes.
Although the coagulation time of cement paste is not directly related to the setting time of concrete, the setting time of cement paste can reflect the coagulation time of concrete to a certain extent, and it is not suitable for Sodium Gluconate retarder and cement Countermeasures are the following: strict control of raw materials, the prevention of concrete condensation occurs in the project to deal with each batch of cement, Sodium Gluconate each batch of admixture for quality testing, to seek the technical characteristics of raw materials, the purchase and use of qualified raw materials.
Ingredients should be initially carried out retarder and cement adaptability test, retarder and cement is not suited to cause abnormal condensation, Sodium Gluconate so the project should be based on different cement, the retarder and cement adaptability test, select the appropriate Of the retarder to determine the appropriate dosage. And according to the design and construction requirements, combined with the use of materials used in the field test to determine a reasonable mix of construction and the best amount of retarder. Because each kind of retarder has the proper dosage, the dosage is too large not only economically unreasonable, but Sodium Gluconate also may cause coagulation, excessive retardation and other abnormal phenomena or cause bleeding and affect the quality of the project.
Determine the mixing system to ensure the quality of concrete. The concrete mixing system includes many aspects, such as the order of mixing of raw materials, stirring time, stirring speed, concrete man time and other parameters. In order to avoid the admixture and cement incompatible, Sodium Gluconate in addition to strict control of raw materials, the choice of a reasonable system of concrete mixing is also very important. Such as mixing time will affect the dispersion of the mixed components of concrete uniformity, thus affecting the work of fresh concrete.