It is believed that some colleagues in the industry were amazed at the particle shape and powder content of the aggregates produced by Huashun Concrete. Mr. Bo also said frankly that the particle shape of his own aggregates was basically “invisible” in the eyes of peers, and the amount of cementitious materials such as cement was relatively small. However, the quality of the concrete products produced was qualified and even excellent, which was basically attributed to the experience and technology found in the tests.
Mr. Bo said that high-quality sand aggregate with excellent grain shape is indeed easier to mix high-performance concrete. However, in addition to the particle shape of aggregate, there are other factors that affect the quality of concrete, such as the gradation of sand and stone, the water binder ratio, etc. In the case of unsatisfactory particle shape, the concrete products with good quality can still be obtained through technical means and reasonable allocation during operation.
So, what should be paid attention to when preparing qualified concrete? Mr. Bo believes that, in short, two points should be paid attention to in the mixing of commercial concrete: “gradation” and “water binder ratio”.
President Bo told China Aggregate Network that high-quality concrete needs continuously graded rather than broken graded coarse aggregate. After measuring its porosity, it needs to be filled with fine aggregate (sand), while the voids of sand are filled with different glue materials: because the fineness modulus of cement, mineral powder and fly ash are different, their dosage should also be adjusted according to needs; In the aspect of water binder ratio, the fluidity of concrete should be well controlled during the mixing; And adding specific additives.
In this way, even if there is a large amount of stone powder in the aggregate, the amount of some rubber materials can be reduced through accurate calculation to prepare qualified concrete. Mr. Bo disclosed that, unlike many mixing plants, which require about 200 kg of cement per cubic meter of C30 concrete, Huashun Concrete uses its own test results to save much glue per cubic meter of products.
For Bo, qualified concrete can also be prepared with 20-30% stone powder content, and aggregates with 5% mud content can be considered as good stones. The cost of raw materials such as aggregates and cement of Huashun concrete has been well controlled. Under the background of soaring raw material prices, Huashun Concrete chose to use its own technological advantages obtained from rich experiments to reuse waste materials, and successfully achieved breakthrough.
Fly ash has a great bearing on concrete maintenance
During the communication, Mr. Bo particularly emphasized the importance of concrete maintenance in the later period. During the test, he used to stack concrete test blocks of the same material and proportion, and continuously add water for thermal insulation and curing. The late strength test results show that the late compressive strength is very unsatisfactory due to the rapid water loss of the upper layer test block, while the strength performance of the middle and lower layer concrete test block is very eye-catching.
He emphasized that when the amount of glue, especially cement, in concrete is large, but the water consumption is not enough, the late strength of concrete is very easy to shrink. He believed that fly ash should be used well in concrete preparation: within 28 days of concrete preparation, the activity of fly ash is basically difficult to play, and it can only contribute to workability and fluidity; After 50-100 days, the cementitious contribution of fly ash will exceed that of cement.
Based on this, Mr. Bo concluded that if only cement is used for the preparation of concrete and fly ash is not used, once the water consumption becomes less, especially when curing is not carried out after arriving at the construction site, the concrete strength will shrink after the water loss is serious in the later stage and the lack of water for hydration. In addition, he believed that the standard for concrete adhesive materials only stipulated the lower limit of fineness modulus, but not the upper limit, which also easily led to the shrinkage of concrete strength in the later period.
Gather talents and technology
Wanted to be an integrator of Jinan concrete industry
It is understood that in Huashun Concrete, the team members who cooperate with the test are recruited by Mr. Bo himself, and several researchers have been sent to Germany to learn concrete related knowledge and technology. Mr. Bo disclosed that Huashun Concrete has provided favorable treatment from tank car drivers to operators and technicians, and is determined to let employees have no worries, become stakeholders of enterprise benefits, and form a virtuous circle between employee enthusiasm and enterprise development.
While reserving talents and benefiting from the experimental attitude of striving for perfection, Huashun Concrete has accumulated a relatively deep technical foundation. The raw material “not picky” has made the enterprise more competitive in the concrete markets of Jinan and Hainan.
In terms of products, the strength test results of the permeable concrete of Huashun concrete test were freshly baked during the visit of reporters from China Aggregate Network, and the strength has reached 26.9MPa in three days. Once the product is formed, high-strength pervious concrete will shine brightly in the construction of sponge city.
Mr. Bo revealed that Huashun Concrete will make good use of its own advantages in the next step, carry out technical guidance, participate in operation and other business models, help surrounding concrete enterprises reduce costs, avoid vicious competition, and then integrate the Jinan concrete market. He said that in the past, the concrete workers used to tease themselves: “From a distance, they look like beggars, but from a distance, they look like rags.” With the backward industry image and the current rising cost, the concrete enterprises are struggling to survive. Huashun Concrete is determined to set an example and make contributions to the upgrading of the industry.
After the rise in the price of river sand in the Yangtze River, many colleagues in the industry agreed that the contradiction between supply and demand of river sand will continue for a long time with the depletion of river sand resources and the restriction and prohibition of mining. It is difficult to avoid the trend of price rise and unstable supply. In the market fluctuation, the price of river sand will challenge the bottom line of the market more frequently. The choice of machine-made sand, like Huashun Concrete, will be an objective demand of sand and stone manufacturers and commercial concrete industries.
In addition, regardless of the price of river sand, facing the uncontrollable raw material cost, it is no longer an illusion for concrete enterprises to extend to the upstream sand and gravel field and lay out sand and gravel production lines, but a real demand. Otherwise, the concrete industry will have a hard time due to the squeeze of upstream raw material costs and downstream payment collection.
What are your opinions on the development of sand and concrete, two closely related industries? Welcome to leave a message to participate in the discussion