CN1100705A

CN1100705A - Method of prodn. and usage of expanding agent for pouring piles

Info

Publication number: CN1100705A
Application number: CN 94107499
Authority: CN
Inventors: 游宝坤; 方瑞良; 韩立林; 颜亨吉; 陈富银; 王栋民; 张淑珍; 江云安
Original assignee: China Building Materials Academy CBMA
Current assignee: China Building Materials Academy CBMA
Priority date: 1994-07-13
Filing date: 1994-07-13
Publication date: 1995-03-29

Abstract

The invention is a special pouring expansion agent (PEA) for pouring concrete piles, a concrete pile with larger volume can be fabricated by adding 15-30% the said PEA, under restricted condition, 0.8-1.0 MPa self-stress can be generated in concrete and 1.0-2.0 MPa self-stress can be generated in mortar, PEA is made from 10-50% calcium aluminate clinker, 10-45% aluminium sulfate clinker, 30-70% active inorganic minerals and proper amount of conditioning agent, through mixing, grinding into powder with specific surface area 2000-3500 sq.cm/g.

Description

Method of prodn. and usage of expanding agent for pouring piles

The present invention relates to a kind of cement expansive material, it is a kind of concrete swelling agent of cast-in place pile (PEA) that is exclusively used in, quantitatively to mix in the cast-in-place pile concrete, be cast in the hole, can be in the regular hour, produce bigger radially and vertical volumetric expansion, castinplace pile and soil around the stake are more combined closely, thereby improve the bearing capacity of single pile of cast-in place pile.

For improving bearing capacity of single pile, just on constructional method, took measures, as enlarging pile crown in the past; Adopt pressure grouting to make stake more become closely knit with native combination the on every side, though these measures and means obtain certain effect, complex process, time-consuming.Set about from the material aspect, the report that improves bearing capacity of single pile is less.

The object of the present invention is to provide a kind of cement expansive material, it mixes the bearing capacity that can improve single pile in the concrete.

The present invention is intended to use this novel material to mix in the concrete, can improve bearing capacity of single pile, and construction technology is easy.Under the situation that improves pile bearing capacity, can consider that minimizing stake number or stake are long, this just can reach and save time, the saving of labor, the purpose of investment-saving, on the principle that improves pile bearing capacity, the present invention and concrete intensifier, the cement expansive material difference when novel material of the present invention and cement uniform mixing, promptly begins to take place hydration reaction after adding water, in the pore after these hydrated product crystal energy filling concretes solidify, play densification, then the crystal of aquation still can continue to grow up along hole on every side, plays infiltration for the second time and fills densification, in the soil, make stake and native interlock on every side get tightr around this crystal infiltration stake.This is extremely important for friction pile, thereby improves bearing capacity of single pile.

The present invention is directed to existing constructional method, a kind of swelling agent that is exclusively used in cast-in place pile is provided, its weight consists of: calcium aluminate clinker 10～50%; Tai-Ace S 150 grog 10～45%; The active compound material of inorganic mineral (monovalence, divalence and trivalent complex vitriolate) 30～70%; And organic properties modifier (liquid agent) of 1～5% with above-mentioned constituent grinding to specific surface area 2000～3500cm ²/ g can make the PEA expanding agent for pouring piles.

Mix the PEA swelling agent (weight composition) of (replace cement rate) 15～30% in Portland cement, just can become and have the bigger cast-in-place pile concrete of swell increment, these are absolutely different with the normal concrete performance.

In the hydration and hardening process of Portland cement and PEA swelling agent, the expansion energy of general swelling agent is smaller, and adopt composite expanded source, calcium aluminate clinker and Tai-Ace S 150 grog, its expansion energy is just bigger, is suitable for the use of cast-in place pile, cooperate with the active mineral material simultaneously, in the hydration and hardening process, participate in reaction,, therefore saved energy consumption because of being natural mineral raw.The user buys the PEA expanding agent for pouring piles according to requirement of engineering, mixes different amounts and uses.

Be a specific embodiment of the present invention below:

The PEA expanding agent for pouring piles is formed (%) table 1

Calcium aluminate clinker	The Tai-Ace S 150 grog	The compound material of active inorganic mineral	Liquid agent
				25	10	63	2.0

PEA expanding agent for pouring piles chemical ingredients (%)

LOSS	SiO ₂	Al ₂O ₃	Fe ₂O ₃	CaO	MgO	SO ₃	Summation
								3.65	16.21	21.42	1.34	28.68	0.71	27.99	100.00

With Portland cement 75～85%, PEA swelling agent 15～25% uniform mixing, pressed cement-sand ratio 1: 2, water consumption is with standard consistency, be mixed with mortar, do time of coagulation, strength trial, free expansion and limited expansion rate, its test method is carried out " GB177 Test method for strength of hydraulic cement mortar ", " GB1346 cement normal consistency water consumption by national standard, time of coagulation, the stability method of inspection ", " the JC476-92 expansive concrete swelling agent method of inspection " test-results sees Table 3.

Test shows: mix 15～30% PEA swelling agent in Portland cement, increase with volume and accelerate to some extent time of coagulation, can be made into to have bigger expansile mortar, produces the self-stress value of 1.0～2.0MPa in 1: 2 mortar of PEA.

The physicals table 3 of the PEA cement of different volumes

Numbering	Cement is formed		Time of coagulation		Ultimate compression strength (MPa)	Folding strength (MPa)	Limited expansion rate (%)
											Cement	PEA	Initial set	Final set	3d	7d	14d	28d
	G ₂₅	100	0	3:15			4:48	63.5	9.8	0.001									0.002	0.003	0.005
G ₂₆					85	15					1:30	2:50	62.8	9.7	0.040	0.050	0.069	0.078
	G ₂₇	80	20	1:00			2:02	61.2	9.6	0.080									0.0107	0.128	0.0135
G ₂₈					75	25					0:33	0:47	60.5	6.6	0.0125	0.155	0.175	0.184

The free expansion counting rate meter 4 of the PEA cement paste of different volumes

Numbering	Cement is formed		Degree of free swelling (%)
							Cement	PEA	3d	7d	14d	28d
	G ₂₉	100	0	0.032	0.049	0.065							0.073
G ₃₀							85	15	0.50	0.70	0.79	0.93
	G ₃₁	80	20	0.67	1.40	2.35							2.77
G ₃₂							75	25	1.57	Spalling	Fracture	Fracture

PEA concrete test method is undertaken by the normal concrete national standard method, and limited expansion rate is undertaken by GBJ119-88.

Mix 15～30%PEA swelling agent in normal concrete, it is compared with blank concrete, and degree of free swelling has greatly increased, and expansion mainly occurs in 7～14 days, and 28 days stable substantially.When mixing PEA swelling agent 20% in the ultimate compression strength, compare with blank concrete, substantially do not reduce, and other volume descends 10% approximately, thus little to intensity effect, under the unidirectional restriction of the ratio of reinforcement 0.78%, in mix the 20%PEA swelling agent, can in concrete, produce 0.8～1.0MPa self-stress value, very significant bulking effect is obviously arranged, be different from other cement expansive material performance.Test-results sees Table 5.

PEA of the present invention is on probation in the many places ground engineering.Static load and dynamic test show, mix the castinplace pile of 20%PEA in concrete, than the bearing capacity of single pile raising 15-25% of normal concrete stake, corresponding in design shortening, 10-20% stake number, or shorten stake is long, owing to adopt the PEA stake, the pilework expense can be saved 30-40%, duration also shortens, so the economic benefit of PEA of the present invention and social benefit are very remarkable, be subjected to the welcome of engineering circle.

Claims

1, a kind of expanding agent for pouring piles is characterized in that: described swelling agent consists of:

Calcium aluminate clinker 10～50%

Tai-Ace S 150 grog 10～45%

The compound material 30～70% of active inorganic mineral

Organic properties modifier 1～5%

The compound material of wherein active inorganic mineral is monovalence, divalence and trivalent complex vitriolate, and organic properties modifier is that to make concrete slump be 16～18 liquid agent.

2, a kind of method of making the described expanding agent for pouring piles of claim 1 is characterized in that: it is 2000～3500cm that each constituent mixture of described swelling agent is milled to specific surface area ²/ g gets final product.

3, the usage of the described expanding agent for pouring piles of a kind of claim 1 is characterized in that: the expanding agent for pouring piles of admixture 15～30% in Portland cement.