Therefore, the main factors affecting the compressive strength of concrete are cement strength and water-cement ratio. To control concrete quality, the most important thing is to control the two main links of cement quality and concrete water-cement ratio. In addition, China State Construction Suqian Concrete tells everyone that there are other factors that affect the strength of concrete that cannot be ignored.
Coarse aggregate also has a certain influence on the strength of concrete. Therefore, when the project starts, the technical person in charge first determines the coarse aggregate on site. When the strength of the stone is equal, the surface of the gravel is rougher than the surface of the pebble, and its adhesion to the cement mortar It is stronger than pebbles. When the water-cement ratio is the same or the mixing ratio is the same, the concrete made of two materials will have higher concrete strength than pebbles.
Therefore, we generally control the coarse aggregate particle size of concrete to adapt to different engineering positions; the type of fine aggregate has a smaller impact on the strength of concrete than the coarse aggregate, but the quality of sand also has a certain impact on the quality of concrete. During construction, Strictly control the mud content of sand within 3%. Therefore, the quality of sand and gravel must meet the requirements of the sand and gravel quality standards for concrete markings.
Due to the relatively large changes in the quality of sand and gravel at the construction site, the on-site construction personnel must ensure the quality requirements of the sand and gravel, and adjust the water-cement ratio in time according to the moisture content of the on-site sand and gravel to ensure the concrete mix ratio. The experimental mix cannot be compared with the construction mix. Than confused.
At the same time, the quality of concrete is closely related to the type, amount, and method of admixture, and it is also one of the important factors affecting the strength of concrete. The strength of concrete can only ensure normal development under suitable conditions of temperature and humidity, and should be maintained in accordance with the provisions of the construction specifications. The temperature has a certain influence on the development of concrete strength. In summer, it is necessary to prevent exposure to the sun and make full use of the morning and evening temperatures to pour the concrete; shorten the transportation and pouring time as much as possible, prevent exposure to the sun, and increase the slump when the mixture is out of the tank; it is not appropriate to intermittent watering during curing, because the concrete The surface temperature rises when it is dry and cools when it is watered. This alternating effect of cold and heat will reduce the strength and crack resistance of the concrete. In winter, heat preservation is required to prevent frost damage. Now, the construction in winter generally adopts the comprehensive heat storage method and steam curing method.