Table of Contents
With the continuous promotion of urban modernization, the use of commercial concrete is increasing, and the number of users who purchase concrete mixing plant equipment is increasing.
According to the situation reflected by NFLG after-sales department, “Some users feedback that the quality of concrete produced is not up to par, whether there are problems with the equipment.
NFLG after-sales department quickly made actions, through field visits and investigations, and finally found that there are three common problems in commercial concrete mixing plants, which seriously affect the quality of concrete. Here are the detailed answers from NFLG engineers:
1. Sand and gravel mixed pile, material bottom pollution is serious
The gravel yard of many coagulation stations is directly connected to the land without concrete bedding, and once it rains, the gravel and soil are mixed; some commercial mixing stations have concrete bedding, but there is no vehicle washing device at the entrance, and all vehicles entering the site do not have procedures and measures to wash their wheels, and the mud carried by vehicles entering and leaving the concrete mixing station every day causes the mud content in the gravel yard to seriously exceed the standard;
at the same time, the bottom of the material pile is not cleaned every day, and the vehicles At the same time, the bottom of the pile is not cleaned every day, and the vehicles crush it back and forth to make it a mixture of soil and stone, and when the loader passes the pile, it passes the soil and stone into the pile of big stones.
The phenomenon of mixing sand and gravel is serious. Many concrete mixing stations have mixed piles of sand and gravel, some even have no retaining wall; some piles are higher than the retaining wall, resulting in mixed piles; some have serious mixed piles when unloading sand and gravel outside the retaining wall. When entering the big hopper, due to the short barrier plate, the material on both sides is mixed up; or the loader is repeatedly loaded with different materials, and the hopper is often not unloaded, resulting in another mixed pile of sand and gravel, and some hoppers even have three kinds of materials.
2. Cement batch is unclear, unclear logo
Commercial mixing station cement tank can only be loaded into part of the project amount, the later need to continue to add, some commercial mixing station of incoming cement not waiting for 3 days retest report to join the cement tank into use, and even some even 1 day safety retest also do not wait, directly into use, which is completely at risk to use. Some of the commercial mixing stations do not even have the 3-day report of the cement manufacturer, which is even more risky.
A large number of bulk cement has been loaded without clearing the tank, so that the audience of different production dates, varieties, grades, manufacturers of cement into a hodgepodge. The correct approach is to add a signboard next to the bulk cement, which should have the 8 markings of manufacturer, brand, variety, grade, production date, incoming date, representative lot, and inspection status.
3. Not testing the moisture content of sand and gravel
About the moisture content test, many commercial mixing stations are not testing but estimating. During the inspection, we saw some commercial mixing stations in the open sand and gravel quarry, the moisture content of the stone is 0.1% all year round, while some of the sand labeled as 3% moisture content in the hopper even flowed outward.
How to measure the accurate moisture content, there must be corresponding measures. The sand in the upper part of the sand pile is relatively dry due to evaporation and sinking, and the lower part of the sand is often supersaturated due to the upper part of the water sinking, and the loader is loaded from the bottom of the sand pile and poured into the mixer, resulting in a high water content ratio, resulting in a large increase in the water-cement ratio.
If the water-cement ratio from 0.5 to 0.65, other materials remain unchanged, the concrete 28 days standard strength can only reach 69%. To more accurately measure the actual moisture content of sand and gravel, one is measured in the mixer loading port, one will be made of sand and gravel quarry backward drainage slope to ensure that the front of the upper and lower parts of the sand and gravel moisture content close.
NFLG focus on road construction machinery technology enterprises, has been committed to researching the most concerned concrete mixing technology for customers.
In recent years, NFLG has launched fully automatic waste wet concrete recycling equipment, environmentally friendly mobile concrete mixing plant, concrete mixing building, precast mixing plant and so on, which lead the technical development of concrete mixing industry while meeting the needs of customers.
We look forward to your inquiry!