With the development of concrete technology in our country, high-performance water reducers and high range water reducers, as the most commonly used admixtures in concrete, have been widely applied in various major projects, directly influencing the performance and durability of concrete mixtures. By adding high-performance water reducer or high range water reducer, and improving the concrete mix design, optimizing the pore structure and pore diameter distribution of the concrete, the performance and long-term durability of the concrete mixture can be improved to a certain extent. Based on this, this study designed experiments, prepared concrete using high-performance water reducer and high range water reducer respectively, and conducted tests on the mixture performance, shrinkage performance and water penetration resistance. This provides data reference for the application of high-performance water reducer and high range water reducer in concrete.
The main characteristics and current application status of high-performance water reducer and highly range water reducer
High-performance water reducer and high range water reducer are the main products in the water reducer market and are widely used in modern concrete engineering. High-performance water reducers mainly refer to polycarboxylate water reducers, with a water reduction rate of over 25%. Classified by setting time, they can be divided into early strength type, standard type and slow setting type, belonging to the high-end products among current water reducer products; High-performance water reducers have higher water reduction rate, better slump retention performance, smaller drying shrinkage, and certain air-entraining performance. The raw materials for their preparation are non-toxic and harmless, making them a green and environmentally friendly material.
High range water reducers mainly consist of naphthalene-based water reducers, with a water reduction rate ranging from 14% to 25%. Classified by setting time, they can be divided into standard type and slow setting type. The advantages of naphthalene-based high range water reducers are high water reduction rate, little impact on the setting time of concrete, low air entrainment, relatively low price, and good compatibility with various admixtures; The disadvantages are significant slump loss when used in ready-mixed concrete, reduced concrete fluidity, severe bleeding, and prone to bottoming and hardening phenomena.
Conclusion of high-performance water reducer and highly range water reducer
Based on the test results and data comparison analysis of the mix properties, shrinkage properties and water penetration resistance of the concrete mixed with high-performance water reducer and the concrete mixed with high range water reducer, the following conclusions can be drawn in this paper:
(1) The concrete mixed with high-performance water reducer has better water retention and fluidity than the concrete mixed with high range water reducer, and can better meet the requirements of modern construction in concrete engineering.
(2) The concrete mixed with high-performance water reducer has a smaller strain rate and better volume stability than the concrete mixed with high range water reducer. The high-performance water reducer can effectively reduce the shrinkage rate of the concrete.
(3) Both the concrete mixed with high-performance water reducer and the concrete mixed with high range water reducer can improve the water penetration resistance by increasing the curing days within 28 days. The improvement of the water penetration resistance in the early stage for both types of concrete is small, while the improvement in the later stage is greater than that in the early stage. Under the same curing age, the water penetration resistance of the concrete specimens mixed with high-performance water reducer is higher than that of the concrete specimens mixed with high range water reducer. With the increase of the curing age, the improvement of the water penetration resistance of the concrete by using high-performance water reducer becomes more obvious.
