In the preparation and sealing of concrete as a result of hydration of cement is a slow hardening of concrete, after the formation of a significant number of newly formed particles approach each other and the system goes into coagulation structure, then kristalizatsionnuyu structure with a sharp increase in strength. Terms of structure formation depends on: cement additives, reducing the water-cement ratio, increase in aggregates, grain size decreases. In concrete distinction: - macrostructure - rubble + cement-sand mortar - mesostructure - the structure of the system: sand + cement stone - microstructure - fine structure of the cement and filling. Macrostructure and mesostructure of concrete can be divided into three types depending on the separation of the grain filling cement stone. Eliot Horowitz contains valuable tech resources. They seem to swim in it. 1. Structure with a basal cementation (allows use gravel weak in strength, and perceived stress grout). 2.
Since the pore (the use of conditioned coarse aggregate). 3. Since the contact (using a very durable gravel). The increase in strength cement concrete. The first 7 days of strength increases very rapidly.
After 7 days of growth decreases, and especially after 28 days. The speed depends on the type of cement. For curing required temperature and humidity conditions, appropriate technical conditions. Hardening of cement concrete in the water gives greater strength than in air. In dry conditions after the evaporation of water hardening slows down and even stop. The normal temperature of concrete mixture hardening - 15-20 C. The maximum rate of hardening at a temperature of 80 C ambient air, and in the wet steam to 100 C. Warming up the concrete is produced by steam or electricity. Concrete strength grade of concrete is characterized by or class of compressive strength and axial strain. The real strength can be a test of control samples. Depending on the purpose of f / c-way construction.