Overview

初始设定时间是将时间水之间的时间段加入到水泥和1mm方形截面针不能穿透水泥浆料的时间，从模具的底部放置在VICAT的模具5mm至7mm中。

Final setting time is that time period between the time water is added to cement and the time at which 1 mm needle makes an impression on the paste in the mould but 5 mm attachment does not make any impression.

Apparatus

Measuring instruments

姓名	CAPACITY /RANGE / SIZE	准确性 /LEAST COUNT
Vicat apparatus	应按原制品制作：5513	-
Balance	1000克	1 G.
Measuring cylinder	100毫升	1ml
停止观看	30分钟。	0.2秒

其他设备

Glass plate, enamel tray, trowel

Environmental Condition

Temperature	27±20.C
相对湿度	90 % (min)

程序

（a）试验块制备

1. Before commencing setting time test, do the consistency test to obtain the water required to give the paste normal consistency (P).
2. 花400克水泥，用0.85℃的水泥制备整洁的水泥糊。
3. Gauge time is kept between 3 to 5 minutes. Start the stop watch at the instant when the water is added to the cement. Record this time (t₁).
4. Fill the Vicat mould, resting on a glass plate, with the cement paste gauged as above. Fill the mould completely and smooth off the surface of the paste making it level with the top of the mould. The cement block thus prepared is called test block.

(b)Initial Setting Time

1. 将测试块限制在模具中并在轴承针的杆下方搁置在非多孔板上。
2. 轻轻降低针直到它与测试块的表面接触并快速释放，使其能够渗透到测试块中。
3. 在开始时，针完全刺穿了测试块。重复此过程即，每2分钟快速释放针直到针不能刺穿块，从模具的底部测量约5毫米。新利18体育官网登录注意这次（t₂).

(c)Final Setting Time

1. For determining the final setting time, replace the needle of the Vicat’s apparatus by the needle with an annular attachment.
2. The cement is considered finally set when upon applying the final setting needle gently to the surface of the test block; the needle makes an impression thereon, while the attachment fails to do so. Record this time (t_3.).

Calculation

初始设置时间= t₂-t₁

最终设置时间= t_3.-t₁那

在哪里，

T.₁=第一次添加水以水泥的时间

T.₂=从模具底部未能穿过5mm至7毫米时的时间

T._3.=Time when the needle makes an impression but the attachment fails to do so.

Precautions

• 轻轻释放初始和最终设置时间。
• The experiment should be performed away from vibration and other disturbances.
• 每次使用时都应清洁针头。
• 每个穿透后，模具的位置应稍微移动，以避免在同一个地方渗透。
• Test should be performed at the specified environmental conditions.

Standard Specification

类型/水泥名称	引用印度人坦达德	初始设定时间，薄荷（min。）	Final Setting Time, mints (max.)
OPC(33)	IS:269	30.	600
OPC（43）	IS:8112	30.	600
OPC(53)	IS:12269	30.	600
SRC	是：12330	30.	600
PPC.	IS:1489,P1	30.	600
rhPC.	IS:8041	30.	600
PSC	是：455	30.	600
High alumina	是：6452	30.	600
Super sulphated	是：6909	30.	600
Low heat	IS:12600	60.	600
Masonry cement	IS:3466	90	1440
IRS-T-40	铁路	60.	600

技术讨论

• 基坑必须既不迅速也不太慢。在第一种情况下，在变得过于僵硬之前，可能存在足够的时间来运输和放置混凝土。在第二种情况下，一个太长时间的设定时期往往会过度减慢工作，也可能推迟了结构的实际使用，因为所需的年龄不足。
• 设置不应被混淆与硬化,which refers to the gain in mechanical strength after the certain degree of resistance to the penetration of a special attachment pressed into it.
• SettingT.ime is the time required for stiffening of cement paste to a defined consistency.
• 间接相关T.he initial chemical reaction of cement with water to form aluminum-silicate compound.
• Initial setting time is the time when the paste starts losing its plasticity.
• Initial setting time test is important for transportation, placing and compaction of cement concrete.
• Initial setting time duration is required to delay the process of hydration or hardening.
• 最终设定时间是粘贴完全失去其可塑性的时间。
• It is the time taken for the cement paste or cement concrete to harden sufficiently and attain the shape of the mould in which it is cast.
• 最终设定时间段的测定有助于安全地去除脚手架或形式。
• During this period of time primary chemical reaction of cement with water is almost completed.

测试标准参考

• IS:4031(Part 5):1988-Methods of physical tests for hydraulic cement (Determination of initial and final setting times)