Cau 3: Tinh luong vat lieu can thiet de che tao 4 dam be tong co kich thuoc 200x400x3800mm.

Cap phoi thiet ke: 1:x:y(z)= 1: 2,5: 3,8 (0,6); ρ= 2400kg/m3; Wc= 3%; Wd= 1%

Bai giai:

The tich be tong can cho 4 dam la:

4 x200 x400 x3800 =1,216 (m3)

Theo thiet ke, luong dung vat lieu cho 1m3 be tong la:

X= 2400/ (1 +2,5 +3,8 +0,6) =304(kg);

C= 2,5.X =760(kg);

D= 3,8.X =1155,2(kg);

N= 0,6.X =182,4(lit)

Co Wc= 3%; Wd=1% nen luong dung vat lieu khi co am trong thuc te cho 4 dam la:

X’= X.1,216= 304. 1,216 =369,664(kg);

N’= [N-(C. 0,03 +D. 0,01)]. 1,216 = [182,4- (760.0,03 +1155,2. 0,01)]. 1,216 =180(lit)

C’= C. (1+Wc). 1,216= 760. (1+0,03).1,216 = 951,9(kg);

D’= D. (1+Wd). 1,216= 1155,2. (1+0,01).1,216= 1418,8(kg)

Cau 1: Cac hinh thuc an mon doi voi da ximang? Lam the nao de han che va khac phuc su an mon do?

1/ Nguyen nhan:

+/ Thanh phan hoa hoc: CaO;

+/ Thanh phan khoang vat: C3A;

+/ Thanh phan cau truc: neu la cau truc rong thi be mat tiep xuc lon → an mon nhanh.

+/ Van toc tiep xuc (xam thuc)

+/ Nong do xam thuc

2/ Cac hinh thuc an mon:

+/ An mon nuoc ngot: do qua trinh rua troi va' va dap co hoc

+/ An mon axit

axit+ Ca(OH)2 → muoi tan

+/ An mon sunfat

muoi+ Ca(OH)2 → muoi tan

+/ An mon dien hoa: xay ra o vung nuoc man, nuoc len xuong

3/ Cac bien phap chong an mon

+/ Thay doi thanh phan hoa hoc de ↓CaO;

+/ Thay doi thanh phan khoang vat de giam C3A

+/ Thay doi thanh phan cau truc lam tang do da(c.

+/ Cac bien phap dac biet: ngan cach VL voi moi truong bang cach o^’p VL chong an mon

Cau 2: Cac chi tieu danh gia chat luong ngoi dat set? Bien phap khac phuc hien tuong tham va nang cao kha nang chong tham doi voi ngoi dung trong xay dung?

1/ Cac chi tieu danh gia chat luong cua ngoi dat set:

- Kich thuoc: ngoi lo.p co 3 loai chinh

+ 22 vien/m2: 340x204mm;

+ 16 vien/m2: 420x205mm

+ 13 vien/m2: 420x205mm

Ngoai ra con san xuat ngoi bo loai co go*' dai 366±3mm; va khong co go*' dai 450±3mm

- Ngoi phai dat duoc nhung yeu cau ve kich thuoc:

+ sai lech ve chieu dai ≤±5mm

+ sai lech ve chieu rong ≤±3mm

+ be mat nha~n ko nu*’t, ta’ch, cong, venh

+ mau sac deu

- Cac chi tieu ve vat ly

+ Khoi luong the tich 1800÷2000 kg/m3

+ Khoi luong rieng 2,5 ÷2,7 g/cm3

+ do hut nuoc theo khoi luong <10%

+ do chong tham phai dat yeu cau (do^? da^'y nuo’c vao ong thuy tinh co d=25mm cao 150mm gan tren vi tri mo?ng nhat cua vien ngoi trong 3h nuoc ko tha^’m qua)

- Co hoc: ngoi phai chiu duoc luc tac dung tap trung it nhat la 70kg dat vao giua vien ngoi voi khoang cach 2 go^’I tua la 330mm