HCSA High-performance Concrete Expansive Agent

Ningheng Brand HCSA High-performance Concrete Expansive Agent (hereinafter referred to as HCSA) is a new-generation calcium sulfate aluminous concrete expansive agent jointly developed by the China National Building Material Research Institute and Nanjing Teheng Building Materials Technology Co., Ltd. When mixed into concrete, this product exhibits a coordinated expansion rate with strength development, featuring high expansive properties, stable expansion rate, safety and reliability in use, and low dependence on later moisture supplementation. Its performance meets China's GB23439-2 standard.009 and the Japanese JISA6202 technical requirements are ideal materials for preparing shrinkage-compensating concrete and filling concrete with high expansion. Particularly suitable for concrete structures with difficult maintenance such as exterior walls, roof slabs, and concrete beams, which require waterproof and crack-resistant properties. When using HCSA to produce shrinkage-compensating concrete for structural self-waterproofing in underground or hydraulic structures, and with complete construction assurance measures in place, flexible waterproofing on the upstream face is not required!

Application Range:

1. Underground structures, such as basement levels in high-rise buildings, subway tunnels, underground parking facilities, storage warehouses, tunnels, mines, civil defense projects, underground pedestrian walkways, and large-scale underground foundations.

2. Construct various water pools, water towers, storage tanks, cave storages, etc.

3. Large-scale structural concrete, extended expansion joints for extra-large floor slabs, or seamless construction.

4. Large-scale frame structures, seamless floor design for airport runways, highway pavements, bridge concrete surfaces, offshore and hydraulic structures, ports, docks, reservoirs, sluices, etc.

5. High-performance concrete, concrete-filled steel tube, abrasion-resistant concrete, and dog dam backfill concrete.

Usage Instructions and Precautions:

1. Considering the compatibility of HCSA with cement, admixtures, and water-reducing agents, it is necessary to conduct concrete mix trials in a lab when using HCSA to determine the most suitable concrete mix ratio.

2. Recommended dosage for HCSA: Standard shrinkage-compensating concrete: 30-50 kg/m³; for high expansion shrinkage-compensating concrete like reinforcement strips or post-cast strips: 40-60 kg/m³; for self-compacting concrete: 60-80 kg/m³. Adjustments can be made to the self-compacting value as per design requirements.

3. HCSA can be mixed with cement, sand, stone, and water simultaneously. To ensure the quality of self-compensating shrinkage concrete, it is essential to add materials according to the concrete mix ratio, especially the dosage of HCSA should be accurate, without under-dosing or incorrect mixing. Otherwise, it will be difficult to achieve the designed anti-cracking and water-tightness effects.

4. When HCSA is mixed with ready-mixed concrete, the mixing time should be the same as that for normal concrete; during on-site mixing, it should be extended by 60 seconds to ensure evenness.

5. During construction, the concrete vibration must be dense, with no missed areas and no excessive vibration.

6. Concrete after casting must not be exposed to direct sunlight. It should be promptly covered with straw mats. After the concrete hardens, it requires dedicated maintenance. The walls should be draped with straw bags to retain moisture or treated with curing agents. The curing period should be at least 14 days to ensure early moisture is key for the expansion effect. During winter construction, when the environmental temperature is below 5°C, insulation measures should be taken. After the concrete hardens, cover it with plastic film and two layers of straw mats or cotton blankets to retain moisture and insulation.

7. Demolishing formwork should be done 5 days after concrete pouring, and extended appropriately during winter. After removal, the exposed concrete surface, especially the outer part exposed to direct sunlight, will dry quickly. It is necessary to cover and maintain it with straw mats or plastic film.

8. After demolding, the concrete should resemble a honeycomb. Remove the loose areas and then repair the holes using 1:2 cement mortar mixed with HcsA.

9. Caution: Use sparingly in environments with long-term operating temperatures above 80 degrees Celsius.

10. Refer to the relevant provisions of the "Technical Code for Application of Compensated Contraction Concrete" when necessary.