After experiencing the "trough" of previous years, the precast concrete pile (especially pipe pile) industry welcomed a round of booming production and sales in 2017. Production equipment R&D has been continuously innovating, and the industry's total output may hit a new record high. At the same time, due to fierce market competition and stricter environmental policies, industry consolidation and adjustment are inevitable.
I. Strong market demand, industry consolidation and adjustment inevitable
1. From mid-2016 to the first half of this year, national fixed asset investment maintained rapid growth. Among them, national real estate development investment kept growing. Although since the "9·30" deadline last year, the state and many local governments introduced the strictest regulatory policies in history, due to changes in housing supply models, various regions increased land supply for real estate this year, and the growth rate of real estate development and construction generally trended upward. In addition, investment in infrastructure (such as high-speed rail, highways, airports, water conservancy, etc.) also grew faster than expected, driving strong demand for precast concrete piles.
2. Guided by the new development concepts proposed at the 19th National Congress of the Communist Party of China, and under the background of the country's vigorous advocacy of green development, green manufacturing and clean energy have become the consensus of all industries. In particular, photovoltaic projects have rapidly developed into a huge industry. At the beginning of this year, the number of piles used in domestic photovoltaic projects continued to increase. The 300mm diameter pipe pile, once marginalized in construction engineering, has regained its usefulness and been widely applied.
3. Because the precast concrete pile industry was in a "trough" in previous years, precast concrete pile manufacturers generally laid off workers, retaining few frontline workers, maintaining low production output and low inventory. They were unprepared for this year's sudden market boom. They wanted to expand production but had no workers available, and production lines were underutilized. While working overtime, companies urgently recruited workers, resulting in demand exceeding supply.
4. Due to the strong promotion of environmental protection and energy-saving industrial policies, various regions have intensified the implementation of policies such as coal-to-gas conversion. The precast concrete pile industry faces the pains of supply-side structural adjustment. Because of equipment upgrades or failure to meet environmental standards, companies have been shut down or even exited the market, leading to increased demand and insufficient supply in some areas. For example, Jiashan County in Zhejiang Province began a special rectification of the pipe pile industry in 2015. By the end of June this year, the number of pipe pile companies had decreased from 51 at the start of the rectification to 30, and production lines from 64 to 40. It is reported that Jiashan County will further advance the rectification, and the final number of pipe pile companies is expected to be only about 20.
According to incomplete statistics, from January to September this year, there were more than 400 manufacturers in the industry, with precast concrete pile output of about 240 million meters.
In addition, the "three cuts, one reduction, one补" (cut overcapacity, cut inventory, cut leverage, reduce costs, fill shortcomings) has achieved initial results. Since the beginning of this year, supply prices of raw materials have fluctuated significantly and supply disruptions have occurred from time to time. For example, cement and steel prices have continued to rise; transportation costs have increased, and sand and gravel prices have continued to rise. Judging from the intensity of sand and gravel governance in various regions at the beginning of the year, in 2017, mine governance and sand mining governance continued to be strengthened, and the supply of sand and gravel aggregates remained tight or even cut off. The continuous rise in raw material prices has had a major impact on precast concrete pile manufacturers, and market competition will become more intense. Industry consolidation and adjustment are inevitable.
II. Continuous innovation in production equipment R&D, broad application prospects
Difficulty in recruiting workers is the biggest困惑 faced by precast concrete pile manufacturers. Mechanization and automation of precast concrete pile production are inevitable trends in industry development. After years of continuous R&D and technological innovation, mechanized production lines for precast concrete piles have begun to take shape. Some companies in the industry have implemented partial mechanized production, but there is still a big gap to truly automated production lines, and much work remains to be done.
To achieve this goal as soon as possible, many companies and professional technicians in the industry are still making arduous efforts and have achieved some results. Since the beginning of this year, relevant units have successively developed automatic rebar threading machines for reinforcement cage seam welders, automatic bolt tightening machines for steel molds, quick-install steel molds without clamping bolts, integral prestress release and bolt removal machines, automatic mold cleaning and release agent spraying integrated machines, etc.
1. Automatic rebar threading machine for reinforcement cage seam welder
In existing precast concrete pile manufacturers, two people are required to complete the rebar threading work at the reinforcement cage seam welder station, which is not only labor-intensive but also inefficient. As shown in Figure 1, the automatic rebar threading machine can, according to a set program, automatically thread the cut-to-length and headed rebars into the corresponding holes of the reinforcement cage seam welder through a manipulator, saving time and effort. 2. Automatic bolt tightening machine for steel molds
Traditional steel molds use manual flipping of clamping bolts, followed by workers carrying pneumatic wrenches to tighten bolts, which is labor-intensive and prone to occupational diseases. As shown in Figure 2, the automatic bolt tightening machine for steel molds is equipped with a manipulator for flipping clamping bolts. After the clamping bolts on the lower mold are flipped and aligned by the manipulator, the corresponding pneumatic wrenches automatically tighten the bolts, greatly reducing labor intensity. 3. Quick-install steel mold without clamping bolts
Traditional steel molds use a considerable number of bolts to fasten the upper and lower molds together. The feeding and mold closing station in precast concrete pile production is the most labor-intensive and unsafe station. Even with automatic bolt tightening machines, the mold closing time is still long due to the large number of clamping bolts. The quick-install steel mold without clamping bolts (as shown in Figure 3) uses a sliding synchronous integral locking (or releasing) method to replace the clamping bolts. On the tongue-and-groove plate of the upper mold, several wedge blocks with inclined wedge surfaces are fastened to the same connecting rod. Driving the connecting rod to move axially along the steel mold, the wedge blocks on the connecting rod move synchronously with the connecting rod and come into tight contact with or separate from the inclined wedge surfaces of an equal number of fixed stop blocks on the lower mold's tongue-and-groove plate, thereby locking or releasing the steel mold. This effectively shortens the mold closing and opening time, achieving rapid closing and locking or opening of the pipe pile steel mold. It features low labor intensity, high work efficiency, uniform force on the steel mold, resistance to deformation, and extended service life of the steel mold. 4. Integral prestress release and bolt removal machine
After precast concrete piles are cured and formed, they need to be demolded and prestress released, and the prestress must be released evenly. Currently, workers mainly use pneumatic wrenches to remove end plate bolts symmetrically one by one. Due to the large number of longitudinal prestressing tendons, careless workers may remove end plate bolts without considering symmetry, resulting in uneven prestress release, causing longitudinal bending deformation, circumferential cracking, or even fracture of the products. This not only affects product quality but also involves high labor intensity, low efficiency, and safety risks. The integral prestress release and bolt removal machine uses fastening mechanisms (electric, pneumatic, or hydraulic wrenches) with the same torque to simultaneously tighten or loosen all bolts. All nut sockets on the integral demolding machine are aligned with the bolt heads to be removed at once, and integral synchronous installation and removal are performed. This reduces labor intensity and ensures product quality. The machine (prototype) has passed experimental verification in relevant companies. Due to different process layout dimensions in each company, it needs to be customized according to actual conditions.
5. Automatic mold cleaning and release agent spraying integrated machine
After steel mold demolding, residual slurry at the joint and concrete adhering to the inner wall of the steel mold are common problems in the production of centrifugally cast concrete products. Cleaning is required before entering the next process. The current cleaning method mainly relies on manual scraping of residual concrete slag on the inner wall and joint of the steel mold, followed by manual spraying of release agent. This is labor-intensive, inefficient, and prone to safety accidents. Since the slag adheres to the steel mold, the cleaning process can also damage the precision of the inner wall. In addition, dust raised during cleaning can cause workshop air pollution. Although some companies have implemented automatic spraying of release agent, equipment that simultaneously performs automatic mold cleaning and automatic release agent spraying is still a dream for operators. As shown in Figure 4, the automatic mold cleaning and release agent spraying integrated machine (prototype) cleans the upper and lower molds separately after demolding, simultaneously suctioning away the cleaned waste slag. The release agent spraying system at the rear of the equipment synchronously sprays release agent onto the cleaned inner wall of the steel mold. Several processes are completed in one step, saving time and labor. The machine (prototype) has passed experimental verification in relevant companies. Due to different process layout dimensions in each company, it needs to be customized according to actual conditions. In addition, to implement national energy-saving and environmental protection industrial policies, supporting manufacturers and technicians in the precast concrete pile industry have developed related energy-saving and environmental protection equipment and construction methods. Some new energy-saving gas boilers, clean energy and supporting equipment, precast concrete pile construction methods and supporting equipment have been gradually applied in the industry, with broad prospects.