Super early strength accelerator for portland cement concrete

Abstract

The invention discloses a super early strength accelerator for portland cement concrete. The super early strength accelerator is prepared from the following constituents in percent by weight: 20-50% of an early strength constituent, 10-40% of quick setting constituent, and 20-45% of a water reducing constituent, wherein the early strength constituent is obtained by compounding at least two of hydramine, an organic salt and an inorganic salt; the quick setting constituent is one of sodium aluminate, aluminum sulfate and sodium silicate; the water reducing constituent is one of a polycarboxylate type high performance water reducer, a high-performance naphthalene-based superplasticizer, and a high-performance aliphatic superplasticizer. The super early strength accelerator disclosed by the invention is free of chlorine and alkali; the 16 h compressive strength of the portland cement concrete prepared by using the super early strength accelerator in a low temperature environment in winter is up to 20 MPa above, so that the portland cement concrete can meet the requirement on quick road repair, and achieves the excellent construction performance.

Description

technical field [0001] The invention relates to a concrete admixture, which is applied to the rapid repair of concrete pavement with Portland cement, and belongs to the technical field of building materials. Background technique [0002] With the rapid development of the national economy, the mileage of cement concrete pavement bearing the economic pressure of traffic is getting longer and longer. In the actual process, the damage to the road surface is becoming more and more serious. How to quickly repair the damaged road surface and open traffic as soon as possible to meet the requirements of economic development has become the focus of attention. [0003] Generally, there are three ways to prepare ultra-early-strength pavement repair materials: 1) using rapid-hardening and early-strength special cement; 2) mixing special mineral admixtures; 3) using ultra-early-strength admixtures. Among them, since the setting time of special cement is relatively fast, and the later str...

AI Technical Summary

Problems solved by technology

Among them, since the setting time of special cement is relatively fast, and the later strength shrinkage is large, there are certain restrictions on output and price, so it is only suitable for emergency repair projects; and when special mineral admixtures are used, there are many ingredients and are not easy to store. The amount of admixture in the process of use is often large, which sets obstacles to the wide-scale use of special mineral admixtures; using super early-strength admixtures is a simple and effective method, but the current super-early-strength admixtures Most of them contain traditional super early strength agent ingredients, which will introduce a large amount of Na + 、K + , has an impact on the durability of the actual project

[0004] Patent CN 102701684A discloses a method for preparing super-early-strength concrete materials, which uses sulphoaluminate cement as the cementitious material, and the compressive strength of the prepared concrete reaches 30 MPa in 6 hours by adding early-strength components, but only Suitable for emergency repair projects; JK series special admixtures invented by Jiangsu Provincial Academy of Building Sciences make concrete harden quickly and have high early strength, which can meet the requirements of open traffic within 4 to 6 hours after use, but the dosage can reach more than 80%; patent In the preparation method of super early strength concrete announced by CN 103467040A, although ordinary portland cement is used as the basic cementitious material, since sodium hydroxide is used as the activator, a large amount of Na + , large drying shrinkage, easy to cause alkali-aggregate reaction, and there are potential safety hazards