What Effects Can Acid Pickling Surface Treatment Achieve on UHPC Panels? Pickling Effects and Process Specifications

Acid pickling treatment of UHPC panel surfaces is a key process for enhancing visual texture and surface performance. Scientific acid pickling can achieve specific decorative effects while enhancing surface adhesion. Drawing on acid pickling experience from projects such as Shanghai New World Century Plaza, Qinglong analyzes pickling effects and process specifications to provide a reference for UHPC panel surface treatment.

I. Core Effects of Acid Pickling Treatment on UHPC Panel Surfaces

Acid pickling treatment achieves the dual effects of decorative beautification and performance enhancement. In terms of decorative effects, acid pickling removes the surface laitance of UHPC panels and exposes the aggregate texture, forming a natural, rough matte texture that enhances the stone-like appearance. In the stone-imitation UHPC panel project for the Dongting Lake Museum, Qinglong made the imitation stone texture more realistic through acid pickling, raising the fidelity to 96%. In terms of color adjustment, acid pickling can slightly deepen the surface color of UHPC panels, make the tone more uniform, and reduce surface color difference, making it especially suitable for gray UHPC panels. In terms of performance enhancement, acid pickling increases surface roughness and improves surface adhesion by more than 30%, facilitating subsequent coating or application of decorative layers, while removing surface impurities to enhance durability. In the Yangshengtang Pharmaceutical Hangzhou Industrial Park project, the coating adhesion of acid-pickled UHPC panels reached over 1.5MPa.

II. Core Process Parameters and Materials for Acid Pickling Treatment

Material and parameter selection directly affect the pickling result and require precise control. The pickling materials are diluted hydrochloric acid or oxalic acid solutions, with hydrochloric acid concentration controlled at 5%-8% and oxalic acid concentration at 10%-15%; excessive concentration easily corrodes the panels, while insufficient concentration yields poor results. The pickling temperature is maintained at 15-25°C; temperatures that are too high accelerate the reaction and cause uneven surface corrosion. The pickling time is adjusted according to the desired effect, usually 5-15 minutes; Qinglong determines the optimal time through testing to ensure clear texture without excessive corrosion. The neutralizing material is a 10% sodium hydroxide solution or a dedicated neutralizer, used to terminate the pickling reaction and prevent residual acid from corroding the panels.

III. Practical Procedure and Key Points of Acid Pickling Treatment

A standardized procedure ensures uniform pickling results and avoids surface defects. Before pickling, clean the UHPC panel surface to remove dust, oil stains, and other impurities, and mark the pickling areas after drying. Apply the acid solution evenly with a sprayer or brush, ensuring full surface coverage and avoiding missed spots. During pickling, regularly observe the surface effect; once the desired result is achieved, rinse immediately with clean water for no less than 5 minutes to ensure the acid is thoroughly removed. Apply the neutralizer, let it stand for 10 minutes, then rinse again with clean water until the surface pH reaches 6-8. Finally, air-dry naturally or dry at low temperature, avoiding direct sunlight that could cause surface cracking. In the Shenzhen Yirui Biotechnology Building project, Qinglong achieved uniform and consistent pickling results through this procedure.

IV. Precautions and Quality Control for Acid Pickling Treatment

Precautions and quality control measures safeguard the safety and effectiveness of pickling. For safety protection, operators must wear acid-resistant gloves, protective goggles, masks, and other equipment to prevent acid contact with skin and the respiratory tract; warning signs should be set up in pickling areas to prohibit entry by unauthorized personnel; acid solutions and neutralizers must be stored separately to avoid hazards from mixing. For quality control, inspect the surface effect after pickling; clear texture, uniform color, and no corrosion spots indicate conformity. Sample-test surface roughness and adhesion to ensure compliance with design requirements. Areas with poor pickling results may undergo a second pickling, but no more than 2 times, to avoid excessive corrosion affecting panel strength. Through strict quality control, Qinglong has achieved a pickling pass rate of over 99%, providing a high-quality foundation for UHPC panel surface decoration.